Prévia do material em texto
SHIPHANDLING
FOR THE MARINER
FOURTH EDI1'10N
BY DANIEL H. .l\lACELHEVEY
AND DANIEL E. MACELHEVEY
ILLlJSTH.ATIOI'-;S BY EAHL R. l\lCi\IILLIN
I)
COR1~LL MARITIJ.\1E PRESS
Centrcvillc, Maryland
Copyright 1953,2004 by Daniel H. MacElrevey and Daniel E. MacElrevey
All righLs reserved. No part of this book may be used or reproduced in any
manner whatsoever without written permission except in the case of brief
quotations embodied in critical articles and reviews. For information ,
address Cornell Marii11nc Press, Inc. , Cenircvillc, Maryland 21617
Library of Congress Cnt.aloging-in-Publication Data
MacElrevey, Daniel H.
Shiphandling for thu rrariner I by Daniel H. MacElrevey and Daniel E. MacElrevey ,
illustrations b,Y Earl R. McMillin.-4th ed.
p. cm.
Includes bibliographical references nnJ index.
ISBN 0-870:!3-51\,l-B
1. Ship handling. I. MacElrevey, DaniPl F.. 11. Title.
YK543.M23 '2005
623.88- dc22
2004014453
Manufactured in the United States of America
Firs t edition , 1983. Fourth edition, 2004
For the sh ipmates nnd friends
who h n pr. shared their hnowledge of the st'a and ships
so unselfishly through the years
CONTENTS
PREFACE TO THE FOURTH J::DITION
ACKNOWLEDGM8l'\TS
INTRODUCTlON
CIIAPTEH 1
Arr ival
XI
XI\"
'i
Master's Trial; Ha rd Right Tu rn at 6 Knots; Hard Lt•fl Turn at G K nti>:
Back ing and Filling; llnlf As tern to Dead in the Water; ~toppiug \1./l.il"
Mnin tain inrr Con t rol Over lleading; H andling a Ship wilh Sternway;
Bow and Stern Th ruslcrs; Turning wi th a Bow Thru::-Lcr; Most EtTt.•clivc·
Maneuver; Approach ing Sha llow WaLcr ; Directional Stabili ty; Efi'ect s of
Bottom Contour on Handling Characteristics; Handling of Larger Ship:;
io Sh a llow Water ; Approaching Uw Pilot Station ; Stopping or Reducing
Headway; Picking up the PiloUMaking a Lee; Estimating Speed
Through the Water by Ship's Prope ller Wash ; Wind EfTe.:t.s on Steering;
Commu1ications with Other Ve~;sel s; Pi lot Aboard; Pilot-Master
Exchange cf Information; Posting of Maneuverin g f'haruclcri st.ics
CHAJYI'EH 2
Shi phandling in a Channel
46
Bank EfTects; Plnnr.mg Ai1eau; Tide [l;Hl CurrC'nl; Types of Ruclders and
P ropulsion Systems; Directior.al Propu ls10n S~·~tcms: EfTcct of Trim on
Handling Cnaracwnstics; lYlakmg a Turn ir· il Channl'i; l' ;;ng Aid:; to
Navigati:m When Turning; Meeting Another Vessel or Tow; Owrtakin g
Another Vcs&el or Tow; U~ing Shiphandling In strumentation ; Thl~ B:t
sics of Squat; Und~J rkcel Clearn·~e·c; Sthtcr;ng;
Five- and Seven-Poi nt Mom;ngs; Mediterranean Moor· Williamson
I'urns; Twin-Screw Ships; Mancuvering Twin-Screw Ships; Low
Length-to-Beam Ratio Ships; Moving Up to Larger Ships; Replci11Sh
ment at Sea; IIclicoplcr Operat ions
CHAPTElt 10
Training
On board Training of Ship's Officers ; On boa rd Training of Pilots;
Shiphandling S imulators; The Hules of Threes; Simulators as Innova
ti ve Tr,1i ning Aids; Ty pes of Simulators; Scale Model-Based Simulator:Ht in ship11undling skillt; has been promptcJ LJy scv1!r;d
fncton; includmg a grcal•'r awareness IJfihc illlpacl marine collisiOI>S and
groundmgs have on the Ciwironment, and new federallegil;lation and in
ternational convention:, affecting ;;hip opc·ration, shipowners' li.tbility for
marine casualties, vessel manning und watch offirt>r training requir•··
ment!S. Training is more technology-driven as suphi~;ticatedshown in figure 1-16. Titles of some usl:!ful books
and pamphlc. ts about pilot b;:mrding lt•cimique,; and facilities are included
in t he l3ibli{lgraph_y.
WIND EFFECTS 0.'\ STEI:H:NG
WIND EFFECTS 0~ STEEHINC;
As lhe ship slows, she begins to fePI the w111d and beco111e more dlfliculllo
slcer if thl! \\"Lalher L; not Lht: bl'"l. The freehoard or ··sad area" that ~he
ship prt!sent::; will he the priucipal factor determining how much effect
the w;tH1 will have on steering, al lho11gh the ratio of the ship's draft lo
Ill I
A ----
A Mall! i~ rad•o
contCA:-d 11 Jl
~
Ladder dS
than 12 rnctv>s (0.31 m) and not more lh:m
16 in:hcs (0 41 rn) betv.een lhe lwad~ "'"'0
rnakong all tread spac .1g bQUoranly
__ Id shed clear ol pilot
hoist and ready lor
emergency use
Fit:- 1-1G. Pil0t ladder pointers.
Special notes
The !!'ltire boardtng area m~st b
5
,
~c, , ,
-o~' : e.,c; J ,-' lJ'..:s~ I 04 , , ~"' orP,-· ,~e(lj : --~e"'.,e
,o~' 6,'b,e ! , ;;'I> tO
~eb ~eTI \\ee .... ~r:::- ·,~ i e\·· ~ ,.-'~0· '
0~ "'~.\,.: :
' iP0
' - ·--- (p-:o-" '
, ' , ' , , .,. : , , , '
I
, ' , , , ' , , ' ,, , '
0 1 2 4 !> 6
Sl•lp·s speed 1n knots
Fig. 1- L 7. SpePd of vessel at. 'Vh ich 'Vind Lakes cha rge. (See footnote 5.)
WI!'>D EFFECTS ON ST8EJW.:G
Conversely, the slup's spC'cJ CHn b~.: n'duccd ton point dctcrmincJ by
that :;a me ratio of wind force t0 sl11 p's speed before you would lll•giu to ha Vf!
problem; steering. This is not to l>U.\' that vou cannot steer nt th:J~ po nt
but rather l11alyou will then need to use the engine U> steer, givinr a ktck
ahead ns the ship !:tarts to come up into the wind. Wh"n you arc tryinr to
stop the :;}up, this can obviously hccome a pr .>blem. Dy puncl11ng tlw en
gine ahead, lhat. is, significantly inrr easing the revolutions for JUst long
enough to !'tart the ship swinging back to the destred headin~:;, you will be
able to control the ship withou:. significantly increasing her hl·ndway. You
should keep in mind that th~ wind wi!l become nn important factor m han
dling the ship as you reduce speed when making arrival or slowing to pick
up the pilot, nnd consider this f :1s
the ship loses headway. When finally dead in the water, the ship will ust.;
ally want to lie beam to the wind. With st.e.·nway, the ship \\ill want to
back into the wind. Be aware, though, thut every ship will behave a little
diiTerently depending on the silhouette that she presents to the wind,
that is, the local ion of the house, deck cargoes, amount of frccboard, and
trim. Only you wi ll know exactly how you r &hip will behave in turn w a din!Ctwn
t lnl requires the bow t.o come through tht- wind- ~i1e might be held on her
heading b:· the wind much iike: a sailing ship m irons, and her spC'cd would
1 ncreasc Wi thoul any signiiican t chR nge m her heading. If the shi 1> is in
stead turned away from the wind (or back and filled around if the amount
of scaroom avai lable will not allow a 1\(;rmal turn), ar.d her stcrn is
brought across lhe wind during the mancuver, the wind will :1ssist tlw
slHp 1n turning. As stcrnwny develops the ship wi ll turr. cnstly as she
bacl:s inland fill in what or
dmarily would be lhP. "wr port. when the c'1gme goes aster11 would be overcome by
the wir>d a, the shi;> gains sternway.
Thir denwnstrnles once again the value of appreciating lhe forces of
wind and current, and the need to add sail training to the curriculum of
our maritime schools. Apart from tho important but more esoteric benefits
of sail training such aG self-discipline, attention to tasks at hand, and ap
preciation of the demands of the ocean environment, there arc important
direct benefits. The skills required to navigate and handle a ship being af
fected hy wind and current are as important todAy as they were in the
year!' of the Down Easters, and these seafaring skills can best be ler.rned
by workin
necessary lo gi ve your call letters to another ship nnly when making
an initiai transmission, and after the iasttransmission of your dis
cussion. Bt•twcen the first and las t transmissio•ll' you need rm ly give
yc111r call sign a t. ten-minute inceruals, although you will h r:r"~fully
keep radio communi cations shorlRr than that.
2. Cull the pilot station, discuss the placen.ent of the pilot ladde r, u p
date your estimated lime of arrival (ETA), and ask if there are any
special requirements for boarding faciliti es.
3. U~:e the VHF to contact the pilot services before arrival at the s ta
tion to discuss the traffic and weather tl:at you might cncount{!r as
you approach the station. This is often better information tha n ynu
can obtain from a traflic control syst.em, which we'll cover in u la ter
chapter when we will discuss traffic movcPlCI ts and control1n gen
cnll. Suffice it to say thnt t:he piiot is able to give you th1s informa
tion and make your arrival Slifcr nnJ easier.
4. When talking to other ~hips, remember tha t wh ile U.S.-flag shq>s
are accustomed to discussing meet.ing situations according U> tht ir
intentions for meeting and passing, ships of most nationalities d is
cuss how they will change coun;e to pass. Therefore, it is pmdcnt for
the marin•!r to state any meeting arrangemenL' ofTicl'r"
a s well.
Use the> ship's whi stle to supplc>mcnt radio communications a nd fu r
ther clarify l• lC planned meeting, whether or not th is i~ requ1n~d by dw
Hulcs of the Road. There is an unfortunate rclucla ncc of deck of1i ccrs I o
us~ the sh1p's wh1stle tnday.
There was a colli,i')n several years ago bclwec>n n U.S. 1\a \:- mari
ner-class support ship and a Liberian-!1ag, Chincse-manned, bulk cnn·ier
at the entrance lo the Chesapeake Bay.ll could have been avoid (•d 1f thes~·
recommended procedures had been follow 2d. The non-English·spcation, the type of ship, or the hull col or.
Technological advancements such as the Automatic Identification Sys
tem (AIS), Bhip to ship. Thto radar and nuionwttc
radar plotting aid (ARPA) presentations although delays while making
calcu lnt:ons and the need ior :nterpreiation r.1akt then. less ""~ful fur
communir.ations th;:.n high-definition, rcnl-timc DGPS-based systems
and systems that use graphic present.Jlions in lieu of nlphanumeric lists
und long, sometimes rambling radio communic$\t;ons. Changes and in no
vations bring new fonn s of communication'> for each succesBive gcl , but the new modes extend the range
and speed of communications so shiphandlcrs can know what is happen
ing several miles away and arrange meeting and monitor progresB of ships
even though they are not yet visible to each other. (Sec also chapter 12.)
PiLOT ADOAlW
After the ship's officer brings the pilot. to the bridge, there a rc several
items that should be covered before the ship's conn is tu rned ov be taken care of, such ns nhap
ing up for the ch this, and always ra1sed a laugh.
"I have an American ship, light draft, and a long wuy to the bridge. Af.
ter going up 30 feet of icy l.Jdder, and cl;mbing six decks, I'll be panting l1~e
a race horse.''
"Yeah, and the first thing you'll be handed won't be coffee!"
"That's for sure. They'll stick the damn bell book in my hand and \:ant
me to WI;t"t! my name!"
This brought a bigger laugh from all in the room.
This is a scene common to pilots from all over the world. Before a pilot
can get a ·J.S.-Ilag ship headed fair, or even catch his breath, he is asked
for his name. No coffee, no sandwich, no "May I take your coat, pilot?" Pro
fessionalism calls for something better than this. Keep it in mind the next
time you welcome a pilot aboard your vessel-let the man eaten !;is
breath, get the ship steadied up on course, hand him a cup of coffee, and
t hen ask for his name.
PlLOT-MASTER EXCHANGE OF INFORMATION
The pilot will n~ed information from the master. While IMO regulations
now require a .::ard to be posted in the wheelhouse showing some of tbe
ship's particulars and maneuvering characteristics, this card is not much
good on a dark night on a ship that is underway. Th.~ same information
will be much Plore useful if it is also contained on a small pocketsize card
that the pilot can look at with a flashlight while starting up the channc>l.
l 0ther information of more use than that found on the ma
neuvering card, which should be supplied by the master. Is the engine in
proper operating condition? Does it respond quickly? Does the ship have
any steering peculiarities? Can she maneuver on heavy oil, or must you
change to diesel prior to reducing to maneuve1·ing speeds? Will there be any
problem letting go Lhe anchor or making up a tug due to deck cargo or the
ship's const1·uction? This and n any other items must be exchanged as it is
obviously to the master' nmuuntnf
inform a lion lhal a pilot shou ld provide lo the master for what is, aftt•r ;,!!,
a f1ui d situation where much is subject to chang~: as the sh ip tran;;;it~· fnllll
42 '\RRIVAL
STING o~· MA.''IEl:\'EnJN('; C' IIAK\l~T bHI~TJCS
can tlwn as.;;umc the corm with a defin it , clcur stat ement so ail 011 till'
bridge know t:1at the cvnn has changedhnnds, make any squipuwnt; the bow
thruster; and any olhcr items pcri.inent to your particular vessel.
The information required by law is general in nature and is for dpc"ific conC:itions and is too oflcn based on analyt1cal cal culations or
Modci tn)'(S, it rs of limited use at best. He:-e ag:.ttn. it is ohviou!'; that t}Jt'
n·ast.er shoulci col lect hi s own data based on actual trials that he will have
conducted at the earliest avuiiable opportunity after taking command of a
G Mosler·f>tlot F:xchnngP, A Position Paper, ln'crnllllonal Mantimc l'liol:;'
Association, February!\, 1997.
44 AHI! IVAL
new vessel. Since there have lwen so few actual tx; uls u nder sha llow water
conditions , any data derived by calculation , 0r from s imulat ions based on
such calcula tions , :>hould only be con:>idcred as l1eing a good approxima
t ion of a vessel's performance. As more tests are e:onducted, such as the
aforementi'Jned El Paso l\1an r'1~ Company and Esso Osa ha tests, there will
be more valid data available. Hopefully more c0mple te shallow water tests
will be conducted in the near future for other classes of ships, as well.
As staterl in the Code of Federal Rc::gulntions:
Aboard et.ch " . . . ocean and coastwise tankship of 1,600 gross tons or
over, t he following maneuvering information must be prominently dis
played," PLc. in the p: lothouse on a fact sheet .
( 1 ) F :>I full and h alf speed, a turning circle di.1gram to port. a nd starboard
t hal sh ows the time and the distance of advance a nd transfer rc::
quireu to alter the course 90 degrees with maximum rudder angle and
const unt power se ttings.
(2) The ti me and ditance to stop ~he vessel from full and half s peed while
ma inta ining a pproximately the initial heading with minimum appli
cation 0f rudder .
(3) For each vessel with a fixed propeller, a table of shaft revolutions per
minute for a representative range of s peeds.
(4) For each vessel with a controllable pitch propeller, a table of control
setting3 for a representative range of speeds .
(5) For ench vessel that is fitted with an auxiliary device to assis t in ma
ne uvering, such a s a bow thruster, a table of vessel speeds at which
th e a uxiliary device is effective in maneuvering the vessel.
(6) The manc uvering infonna tion mus t be provided for the norma l load
a nd normal ba llas t condi t ion for:
(i) Calm weath er- ·wind 10 knots or less, calm sea;
(ii ) No cu:Tem ;
(iii) Deep w t how tlw pilot in
volved in such a turnc\·er !'eels nbou t it. Gt\'e ~he t-> ilot sufficient li me to p: t
his eyes adjus l
ciated by alt on the bridge.
The aura of professionalism that surrounded this pilot's actions is a;;
much a product of e.'tperi£nce and attitude as it is the result of t(chnical
training and sllill. It is essential that all seagoing professionals develop
this aspect ofdwir work along with their technical sR.ills. Professionalism
is a learned trait, qualitativein nature and difficult to define. We have all
observed the shipmaster or pilot who is obviously in command of a situa
tion, a person wl.o is a professional, and the manner in which he performed
his work was, of itself, a de.fi.nition of professiondism.
Because of the uriqueness of the seagoing environment and of the sea
man's work, the "showboating" often resorted le> in other professions to
impress one's peers and superiors is out of place aboard ship. Dectsion·
making committees and the substitution of rhetoric for content are mecha
n~sms that r·an be used to hidt! inabLlity in some fields. Not so aboara sh1p
Here you must be t.:ompefr>nt .1nd confident about your work, and any lac~-:
ofslulltnill becvme evH 1ent m a short time. Further, you must also appear
competutt to those you •uork with so they too have confidence in your skills
anrl re$pond tt;ithout the Jelay or questioning that leads to confusLOIL
Since professionalism cannvl be learned from a booh, those who teach
a/ the various manttnw amc1erllLes and schools, and more import a ·ztly, the
!lANK EFFECTS 17
sr:l!lor officers aboard siLlp, haue a responsibthty to nurture tts develop
me;zt among )'011 TIIJ"r officers just start iflg out in their careers. Th ts offers a
signi/ir·.l/lt chollPnge 111 (17! ern wl "'' :t is {ash•onal>le tu Jcn:;.:rc!c tn:c!:
tional slull~ and qutet competence. Demand p.-..{t!ssiorwlism {rum all
aboard. Ships mnnot fur. cl ion prop~.:rly without u singular lugh s/anduu!
of performance and sense of responsibility.
DANK EFr'ECTS
!11 the portion of a river where the channel narrows, the ship begins feeltng
the steep bank close on the starboard hand. She wants to sheer to port as
the combination of suction on the starboard quarter and, to a lesser de
gree, the cushion of water built up between the sh1p's starboard bow and
the bank become more strongly felt. The problem is compounded when it i,;
necessary to siow the ship; tne rudder loses some c!Tectiveness as the flow
of water il:! reduced, while the suction at the slcrn, which is primarily n fuc
tor of the ship's speed through the water, remains s~rong. The ship nnwt
be moved further from the bank and t.he rudder angle increaHed.
But what if t.he ship gels so close t.o the bank th:.t she starts lo sheer
across the channel? Don't redt ce engine speed, because at thiH point. the
rudder needs to be as effective as possible unJ any reduction in the ship's
speed that. might result from a change in engine revolutions will be nc~~!J
gible in such a short period of time. RaU1er, let the hcau fall a fi-w degrees
ofT course ncros~ the channel while maintaining some rudder angle t.o
ward the near bank, and irtcrc(lseengine speed so the flow ofwuter past the
rudder increases significa.1t.ly. When the heading has changed a few de
grees toward the cenlcr of the channel, increase the rudder angle toward
the near bank to first. check the swing, and then to bring the ship back on
course as she reaches the center of the channel, or at least reaches a dis
tance from the closer hank that. will allow hf'r t.o be steered safely. Only af
ter gett:ng away from the bank should the engine speed be reduced so lht:!
ship loses some headway and the tendency t.o take a sh.Jcr is reduced. It is
obvious that. a ship should not proceed in a narrow channel at Jullmancu
vering ;;pced, :>incc she would not have any revolutions in reserve !'h!ll!ld
lney br required.
Remembcrt.oo that.! ship 'Yants lo movu closer to a bnnk , dui' to the in
en nsecl flow of water and t.h advan tage. Th1nking ahead and pianmng maneuvcrs bn~cd on
an u nderstandi ng of the forces aclt nt; on the .-ht;J. much like a chess mas
ter who wim; by pla nning severa l mo,·es at one time so they foll ow 111 a
logical order, is essent ia l if a ship is to uc muvcd efficiently and safely.
The pro·css of thinking se-.•eral steps ahead u:1dcrlies every mancu,·er
d iscussed in thi s text. Its importa nc~ i.t yot: r development as an excel·
lent s hipha ndler, ra ther than just as an acceptable shtphandler, cannot
be exaggera ted .
Un ·!ers tand ship behavior, prope rly reduce ship's !'peed, use cxi,ting
conditions and forc('s to advantage to a;;stst the ship's rudder and t nhinc
in maneuvering and, most important. thinfl alwnd o{th1' ship so that she is
reacting to your orders rat:1cr than your orders uctng 1-,rivcn in reaction to
the sh ip's hehavior- thcse a rc lhe basics of e'cellent shiphnndling. Tlunk
ahead of you r ship a t all t imes.
TIDE AND CUHHE:'\1
Many rivers cannot be negotiateJ by larg(•r ships without a fair t ide since
a head current hinder:> them in making turns. As shown in figure :l-2, a
fair current helps the s tern around u bent! when it s trikes the qunrtl!r, ~o
th e s tern comes a round at n greater rate. At the same t 11ne t he bow i,; as·
sisted by the eddy currents rcf1ecteu out of the be nd and the lack of current
on the bow on the point :,ide of the bend. ln contrast, for a given speed over
the bottom, a ship stemming a tide has a greater flow of water passin ~ be
tween her and the bank, retarding the stern 's motion around a tu m and
forci n t~ the bow and ship bodily towurds the bank (fig. 2-2).
Since a ship that is closer to the bottom is more di ffi cult to control, high
water makes the pilot's job ea::;ier asicie !rom just pu lling (:llOU t~h water
under a deep lonJ ecl ship to ens~ re that she is in the desi rable slate ofb···
ing always Hf1oat! lly moving wi th a rising ttde to ensure u fatr current and
dcc per water , a ::;hip is using both ude and cur rent to her be,;t advantngc.
The cu rrent changes a t each area or a chnnr11·i aLa di!Tercntt imc an·i .s
affected by severa l factors such as freshe LS rcsu lti n~ fr0m henvy rains
u pri vc r and s trong ofT- ur onshore wi nJs ;;o tide·~ may orcu r a t signifira nil:
di ffercnt t irr.es tha n predicted. Keep a ~cam an's eye on ~!tc cu n ent. Dc•
vclop thehab it of looking a t pilings, uunys. and !Jth.·r !i xl'Cl objl't'l to
dwrk the actual cu rrent agamstthat wi111 .. h ha:; hcl:n pred ictt:d unt tl rt lime how effective the
rudJer 1S and how the ship will respond to varying amounts of rudder an
gle. Unfortunately, the tendency towards smaller rudders on larger ships
has made the shiphandler's task more difficult.
Again, plan uhead so the rudder and propulsion system can be used as
effccti,•ely a.-> possible. Prorcnd at a moderate speed so greater engi11C rev
olutions can be used as needed to increase the flow of water past the rud
der and thus increase the rudder's effectiveness without creatir.g other
problems. Uy using thf' engine in this m &nner, for only as long ns needed Lo
obtain the clef.ired rcs·Jlts, the shiphandler can usually overcome any in
herent deficiencies in lhe ship's design. This tactic is particularly eiTective
'I YI'ES OF HUODimS Al'\D PHOI'l'l.SION SYSTE~IS .)1
with a diesel ship since immrdiatc, large changes in revolutions can h,• bCl'll used as a hHs1s
for recommend in~ that VLCCs be fitted with Lhi ;; type oi'propulsieu of a s hip fitted with a variable-pitch pro
pelle1, the flow of water i)3St the rudder is s ignificantly dtsnpted
unle;;s the pitch is reduced very gradually. The adver se effect on
s tee1 ing is significant. The propeller cann(lt safely be put ~l zero
pitch tc reduce the ship's headway s ince this completely dtSI"U\H5
the needed flow of water t.o the ruddec.
2. A variable-pitch propeller going astern is less effective than a ron
ventional propeller. This compounds the aforementioned steet;ng
problems since, because it is more difficult to drift the way ofT a ship
fi tted with a vari able-pitch propeller, it. is often necessary t~ use the
engine astem for longer periods of time to soop her.
WJ-.en app-oaching a berth, Jock, or pilot station, it is therefore nece5-
sary oo start slowing a ship eq·.llpped with this type of propeller S;)()~e~ than
would be requ:t-ed with a conventional propeller, and to then use mtrumum
pitch to st.eer at slow speed once headway is sufficiently re~uced.
Since a variable pitch propeller is normally turning at htgh RPM, even
when in position and soopped at the berth at zero pitch, be sure to keep
stern lines clear of the water when docking. Inform linehandlers on th .?
dock that this is necessary, as a line can become fouled in this rapidly
turning propeller in an amazingly short period of time. A tug working at
the stern m"Jsi also be cautioned.
DIRECTIONAL PROPULSION SYSTEMS
In collabora'ion with Captain Paul lues and Captain Earl R. McAfillin
More ships and tugs are !:icing l:;uilt with new types of propuls ion and r .le;.
der configurations including the Voith-Schneider and Shot.tel systems
used orima rily for tugs a nd self-propelled barges and Azipod p!Opuls!On
systc~1 s being used al t hi8 ti me prima rily for pas~cnger vessels, a fe;••
tankers, a nd &ome sp!'cia l-purpo8e vessels such a~JHEGTJONAL PHOI'ULSJO.'\ !->YSTE~IS
Ad ua ntagcs
This is primarily a tcYton hnndli,lg oc~angoing 5hips so this discus;;ion of
umniatrectiOnnl propulsion wtll focus on the uses of a generic Azipod sys
t('m rather than other om nidirec~ional systems that are more commonly
usec on _,mallcr ves:;cls. There a~·e mure similLtritics than differencts bl·
twccn tlw vanous omnidirectional systems so, v·it.h a few exceptions, any
discussion of advan tages, disadvantages, standurdized lcnninolugy, .tnd
commands for Azipod systems also ;.:pply to other omnidi recllonal pn>pl.ll
s ion sy::.t ems.
There are some obvious advantages that make omnidirectional :-;y:;.
tems particularly att ractive for passenger ves3cls and, loa ll·s~er extent,
some other sprcial-purposc ships.
• Electric generators power the Azipod system and lite dri ve motM~
are located at the stern outside the hull. This gives the nnval arclti
leci some freedom in design.
• Machmery is located in more appropriate areas within the ship':;
hull sohigh-revenue space:; arc available for st.1tcrooms nnd pns
scnger senices.
• A shaft is not required to t ransmit power to the pro:>eller.
• The system is inherently q·1ietcr so noise is reduced in all areas of
the ship.
• The system is safer because the engine does not have to be slopped
and rcvr>rsed to go aslcrn. This el iminates the r isk of losing engine
power that if always present when conventional diesel eng-inl's do
not restart while mancuvering ahead nnd astern. ·
• Air compressors can be significantly smaller ~ince the engine will
not be repeatedly stopped and restarted.
• The shi ps are highly mancuvcrable because the dri ves arc variable
speed and directior.al with controls for twin drives that can be split in
Harbor ~node so p0wcr is applied in two ciirecti"ns Himu ltancously.
These and other ncivantagl.'s a re obvious to cxpenenced nwrincrs who
maneuve:r ships filled wi th Az;pod propulsion nnd snmlar Hy~t.
The potential for s ingle-person opera tion to stef! r and maneuver
creates a very real risk that the concepts of bridge resource man
agement will be ignored.
Computer-assisted opera lion of the Azipod system can be used in
appropriately to dock, undock. and maneuver in restricted waters.
• There is also some expectation that Azipod systems will be mo re ex
pensive t ms.
Each of these points is discussed in more detail in the following pan
graphs.
An Excellen t Aid, but R ecognize J,imi ts
It ib possible to use brute power to rnancuver Azipod vessels into SJtuu
tions that no skill ed sldphall J ler wculd accept. T he problems t hat incvit,_
bly occur whe n high lw rsepower replaces good c;eamanship can be masked
when shipha ndlcrs use th e system continu ously a t full or near full oower.
This occurs must commou ly when leRs experienced ship's offi cers op~rate
the system. It is par l.Jct.larly common when using the joyst1ck nnd con'
pulcr input. Skilled mnr im•rs and pilots .lever work a ship 1t JIS p,axi-
ll!HEGTIOI\AJ. I'HOI'l '1-'10:.: ~ YSTE:-IS
mum, antl they a lways have opt1ons as they ma!"'eu\'er, dock, or undnck
\Vher, tiw ship is put i:lto si tuations that requi re continuous use of thc
thru!"lascs or
shift s, curren ts arc stronger lhan anti ~ipatl'd , or c)llwr conditions change.
Exp"rienced masters and pilots bringing con\' t.: nt 1c nal : dt•sJgn i ~ L;•si
ci11ly rhr. same. Pods containi ng electric drives nrc fitted nt tlw str l'll of a
vcsSt•!. Thr pods arc rol ,tted 3GO dt•!{rccs :;o th L' din'ction of thrust r 111 b•.'
56 SHIPIIANDLiNG IN A CHANNEL
c!Hmged and even reversed by rotating the PC'd or revusing Lhe direction
n.nd speed of the propeller mounttH.I at the forward end of the pod. The ex
ternal electric drive receives pow~r from t he> !';hip'~> diC'3t l ~P.ncrntors. :\
typica! in&t.allation is shown in figure 2-3.
Some in '>tc.llations also havt: a fixed pod on Lhe centerline. Naval archl
tect3 and huilcicrs have plans for other modifications ofthis Azipod design
that. include having a propeller on both ends, one pulling and one pushing.
There are a!so desig.ls Lhat. use a conventional shaft nnd propeller with a
pod immediately astern of Lhat propeller. In port the pod acts as a s tern
thrust~r.
Azipods are controlled m sevet a! ways . Typical controls include non
follow-up lever controls, conventional wheel with throttle controls, large
knobs, and combination controls that simultaneously rotate to d e termine
the direction of thrust, and move forward and aft to apply more or less
power and determine the direction of pro;>eller rotation.
Most systems also have ajoyslick control to change the orientation of
the pod and the drive motor speed and thuL the direction and thrust of the
propeller. The systems can be controlled by R helmsman at a conventional
Fig. 2-3. Typical Azipoc' propelled s hip. Courtesy Kvaerner-Mass Yard :AI.I'R0Plll~~IO!' :-YSTE~iS
helm , tuud, or by the officer on wntch, n· a .:onning ol!icer operating tht·
system from n console, w1th or Without computer ns:-;istanCl! (fig. 2-·1 J.
Use o(!ittJ.r:dard Trmttnology
The syst(:mS have various operating modes. Terminology to ck.;.:rihl' tht:
arrangements and modes varies from on1• manufacturer and vessel opera
tor to another although must can be broken down lo an "opl'll water" o:
"cruise" At Sea mode, a Harbo~ or maneuv~I;ng mode, and a Do.:king
mode for use when actually gning- alongsideor l 0.avm~; a berth. The mode:,
cun be further cal(::gorized a~ automatic or manual.
Typical modes and commands in use include: '
Company A
1. Call Cumbi (Cruise)
2. Separnte RP:\i(Crui~c)
3. Call iV.imuth l~1ancuvcr)
·L Call J oystick Dynamic
PosltlOmng (:\laneuvcr
a. High speed
b. Low speed
Compuny H
l. 0;1en Sea (;\L s, .1;
2. ~fancuvcr Direct (;\t
Sea)
:l. Azmlard
of thf ctn lo.:rline.
FuiiJ•Il"'"r i~.ilahle .
• Pod movement is synchronized so pods 1nove in unison.
The pods, and thus the ship, can h~ steered using the helm, whed,
mini-wheel, autopilot, or differential positioning syslc•m.
Powt•r At Sea is about. double the horsd to zero ifope rnlors a ttemp\ to :·otmu the dri ves to an
gles greftlC'r than 35 degrt'es from the rent erh :1e.
liarbor I or Maneuuering; JhJf!
The re are some vanations a mon15 system s but wnt:!n most Azipods arc in
the "hnrbor" mode
• Power Hi reduced to approximately 507." of the power available ut
sea.
• The pods can be rotated 360 degrees.
• The pods can be rotated independently and be used at different and
total variable angle!> (there are e>:ceptions with systems that allO\"
only one pod to be rotated).
• Steering is done by pod control, combi-controls, differential posi
tioning system, joystick, non follow-up steering, and by varying ruv
olutions of the port and starboard engines ahead and ons to sel l:lct these configurm.io:1s.
Keep in mind while discussing these configurations that the propelJc:r
~~on the forward end oft he pod and tuming ahead as indica Led by Lhe a r
rows when the pods are operating in the normal position .
2 Strering Control SyslPm.~ for Azipod, Electronic a nd Ma rine Research ,
!Terlev, Dopr n channel when the pod configuration in figure 2-G is being used
('ut fiJ! ~Ir pl.'un Pau l !vi's, l nslrurl or RT~I
STAll Ccnter, Da llln, Flo rida , F cbruary 2002.
SIIIPHANDl,ING IN A CIIA:-\Nt::L
Fig. '2-7 . Harbor .Mode configm11tion #2.
An instructor at the RTM STAR Ce!lter, a facility where many pas.:>en
ger Hhipmast.ers and pilo~.S are trained, refers to this arrangement. as tl.e
"bicycle mode."' This term i!; quite descriptive of the manner in which
ships are handiPd in this arrangement. For example, the port control JS
moved ahead 11nd the slarboard control is pulled back to turn the shi(!'
head to starboard. 'l'his is the same motion as t.he handlebars of a bicyciP
where the left. :;ide moves forward as t.he right!:!ide is moved back to turn
the bicycle to the right TI1e two handles are in line, that is, the set.t.ing nf
both propellers is the sane, to move straightjust as the handlebars of a bi
cycle would be in line when moving straight ahead. The angle of the pods
also helps stabilize th~ ship at slow speeds and, by increasing the setting
of one pod only, the stern can be held against a wind to assist. in keeping
the ship on a desired h eading at slow speeds.
There is some dispute over the usefulness of this configuration. Ship
handlers arc using thi8 arrangement less often and some companies are rec
ommendinr; against using Azipods in this manner. Mariners report eome
difficulty in maintaining course in narrow channels because Azipods hnve so
much power that even small changes in settings can cause unaccepteble
changes in headin~. At the same tin1e, many pilots seem to like this configura
tion when proceeding at slow speeds. The information is o;.Tered so ship
handlers can try this configuration and decide for themselves whether the
configuration is useful, a11 has been the theory, or that the parallel pod ar
rangement '~ith ronvenlional l
F1g. 2-b Docking Mode ronfiguration 113.
when docklllg pori side to, is set parallel to thr ccnlerl ine. The pod nwa~·
irom the berth, the outboard pod, is put in a thn'c o'clock pol';i lion relnti v••
to the crn terl1ne (fig. 2-8 . In this posit ion the fore and nft uni l is uscci to
move the sh ip ~.head and c
them. There are several advantages to limiting and standarcizing the pod
position including the fact that standard commands can then be adopted.
Pilots using Azipods at the RTM STAR simulator tried va rious nwth
ods and commands for conning a ship wh!le swnding away from the con
oole. In other words, lhey look ihe AziJ)od system to thn fin a l s tage of
developmen t. by in tegrating the controls into proper ~hip opC'!.ttions. Two
mcthodo were used to conn the ship. Both work well.
In conf:gu:-a iion #1, sll:.orint; and engme c"''IITtands 11re iJII e·1 :n !1.1'
same mannt!r 'LS dune for conuentionai sh1ps.
In configu:-ations #2 and #3, the pod s !cere 1 usitioncd by degre,•s or
clocll positions relatiue to the bow a:1d cngl.'W orders nre f.( iu ,~n in JWr
in n nuanner that violates all nccer-ted principles of bridge resource .nan
agcment. The bridge ere .v and pilot work as a team to safely move the >Lip
onc.:e commands and configurations are standardized.
A good ca:-·pedence using the Azipod sys
tem, rt>commended s~andard commands are
l. Engine comm 1nds use percentage of power from zero to 100 in a for
ward or reverse diredion in both the At Sea and Hubor modes.
?.. Conventional rudder commands in degrees to port and starboard
are used and executed using a standard wheel-type control at sea.
:l. Pod configuration use clock settings relative to the ship's bow in the
llarb1r mode where e n~:, ines arc u sed primarily in fixed pos:tions.
Azipods evolve to the next level for sh ip operation when standard com
mands and co ntigurnt.ions are adoptE:d. The conning officer is relie"ed
from distracting st.ccl'ing n ~po:1sibi!ities . The bndge crew is agair. work
mg al' a U>am in compliance with inte;-nationaily nccepled standards for
hndge :-esourcto muna1~emcnt w1th the pilot or conning officer 1'1 contr oa of
l1P.VlgHI ion.
Compu:a Control
A computer-controlled option is avmlable 111 all modes. Controls for the au
tomated or· Cllmpatet-controllecl mode di!Ter from one sh1powner and man
D!H~C riONAI. PHO!'Ul SIO:-\ ~YSTE:-1~
ufacturcr to nnolhl'r hut all ~re similar. ~1o!;t arc t'Ontrulll'd by a joy,:!,·k
for input. of desired resullanl power, sprcd, and c!irJrtion or\'I'SSl·l ii 10 \ t'
ment The systcrn's computer trano5late;; j:, .; tic!: il1J.ut liJ cr.ginc.: " P•~l:~.
P•)d rotat1un, and bow lhru~t.::·· Qrders in tlk m..:nncr dctcrrn inccl by pn:
prcgrammed algorithms.
Sl11pha:rdlcrs must remember they nre cunlrulling re«ultant JIOtn•r ,
sp~c>d, a.td ucsscl mnucment, not actual rct·olutw11•: und clir,·r·tiOII u_(
thruster, engwc, and rude/er mot't"llenfs.
Automated controls nre not new for open wat{~r since gyro-corltn.dl.·d
~leering has taken ship;; from port to port for half a century. Cornputcr
control for Azipod operationin harbor conditions is obviously more com
plex and it should be used with some care.
Interestingly, cxper·ienced masters, mates, . .md pilots arc more ·at • inu:
about. computer-controlled operation thar. less experienced ship's officer:;.
Skilled shiphandlers, be they shipmastcrs, offic~rs, o.· pilow, , :m.>
trained to plan ahead and be proactive. Computer-controlled :-ystem~ ar.~
reactive. This uifTerPnre is importnnt. !\o mhttl~r how quic.:kly lhe :;y:;'l!ll l
dP!.ects and reacts to wind shifts or set. the sy~ternl'annol, 1.t i ii "'· ar. r!
plan ahead based on past experience and local knowledge. The be:>t ~Y!' ·
tems detect leeway and :;et. almost. instantly, but they t~re :: till tl::-.• t ing
rather tha•1 anticipating, as a trained shiphandlcr wo11ld do.
Experienceci shiphandlers consider crP.w skills, anticipa te l'Xt,•rna i
forces nnd known ha:cards, and !mow whnt. works and what ~l cJcs not worJ.:
in a particular situat.ion based on experience over a period of ycars. Th0y
also adhere lo lhe concept of"most effic~ent. maneuvcrs~ and use a mini
mum of commands and maneuvers t.o accomplish a !.ask. C'omputcr·con
trollcd systems will overn·ork engine and steering tD power th rm•~::h a
maneuver that experienced shiphandlers would avoid. In the computystcm
s hould not be u~ed nea r docks and fixed objects. At a minimum, g ood sea
manship seenw to support a "one ship length rule" to at.!cide when to changt•
ji·om autom atir: to manual control.
The compu~cr often applies power in an unpredictable manner. Lin es
are parted wlwn the compu:.er a ttempts lo move a ship laterally r ath er
than at on e end only. Most systems allow the pivot point to be shifted to a l
low for this m nn euver, but the system becomes progressively less a uto
mated as the pilot make& more of these adjustments. As one pilot with
experience handling Azipod vessels slated, "You fmd yourself trying to
outguess and cor·ect the computer ."'
One pilot. compared computer control to having un apprentice pilol
aboard. The apprenti .::e hnndles the ship but. the experienced pilot is con
gtanlly moniluriog the npprent.ice and using skills lea rned through expe
rience to undo the mistakes of the a pprer.tice. It is usually easier and safer
to do the job yourself. There is a reason to do the extra work to train an ap
prentice, but it is difficul t to rationalize the sa me effort to supervise a com
puter. Automatic : outrols arc an advance in an anchorage or when us ing
adaptive autopilot at sea but the "one ship length rule" is good seama ns hip
when dockin5 or undocking.
As previom;ly d1sc.ussed, pilots see a n increasing number of s ituations
where ships ~re put. into d &ky 'lositions because the computer doe!' not
kn ow when an 01·dued maneuv hip length rule" fo r shifting ofT computer contn, l.;; seems rea ·
gonaulc except in the most basic tund1l ions . Obviously, pilots and ships' of
ficers may waut tu shift to ma nu al controls long bcf01 e that point. This
r. Captain Earl H. McMillin, Canavera l Pilots' Association, December 6, 2003.
DIHF.0'1'10NAI. PHOI'UIA'>ION SYSTI·:M~ I · ~ ) (
may change as programming and input to the systems become;; mnn• :-o·
phist.icnlcd.
!Jrid~;:t! R es(Jarct! Alarw gcmenc and / .;:tpod.•·
Azipot!s is clenrly not
one of those modifications. Unfortunately, this has become a common
practice aboard too many ships where t he pilot bc.:omcs an adJunct., an ad
visor , to the bridge team and the mates sta nd aside while keeping records
and providing support with little or no knowledge of what is being do1w M
the details of a ny pa~sage or docking plans.
The practice totally disregards the imr~w whnt
t ricks he is puiling out of his hat."
68 SIIIPHANDLINconune1 ·
cial simu lator facilities operated by MarineSafcly In:.crnationnl all(} ulh
ers, are using rapidly evolving simulacur technology to provide th;.,t
training
!:iimulation h~li still not reached a level w!tcrc it re placeR hanc.!s-011 ex·
peril' nee, but it is being used cffcclively fo!' ini.ial and •. pecializcd training
and as a forum for experienced mn1·iner;; to compare tcch niqllc" and t•v:J l
unlc their own performance. More advancl,d simulatur3 are al~o lwinj!
xi
xii PREFACE '1'0 THE FOURTH EDITION
used for license examination", reccrtificalions, and evaluations of mari
ners in apeciaiized skills. Dis~u.:wicns of shiphnndling have moved from
coffee time to class time and the profFssional is better off for the rhc·1ge .
This fourth edition of Shiphandling for the Mariner is updated to in
clude ih new material used by the RTM STAR Center and
other facilities for programs to evaluate and license mariners and pi
lots-is the basis for expnnded sections on simulation for continuing edu
cation and training. The mateiial provided by Captain Charles Pillsbul')'
of MITAGS, Captain Orlando Allard from the Panama Canal training
facility, H3rry Crooks from the RTM STAR Center, Captain Richard
Beadon from tr.e Seaml!n's Church Institute school, Petec Barber from the
Southampto'1 Institute, and Captains Robert Meurn and George Sand
burg from the U.S. Mer~;hant Marine Academy CAORF facility at Kings
Point on the same subject has been retained.
Changes and nuggestions sent to the author by working mariners and
instructors at various maritime academies and schools are added with
PHEVACg TO TilE FOUKI"II 1-:lll'l'ION xiii
each edition. Hopefully, others will send material for future !'ditions sr1
this text remains as up-to-dale and ns ust~fu! as pos~:bJe for !Wago1n1
! pro
fessio,llll s working to improve their shiphandling skil ls.
Lastly, photographs of new :>ropulsion :;ystems, bridge l nyout~. navi
gation Ctjuipmcnt, hull designs, n·1d upgrach:d simuiHtors hnvt~ ht·cn
added throughout tl.w text. The photographs und new lablt•s showing t lh
latest dnt..1 on squat and undcrkeel clearance keep the book cur-rPnt
Practice mancuvers are again i:1cluded with tbc text. The cxcn:ises can
be used with this book ns a self-taught shipboard shiphandling course or,
better yet, they can be part of a formal ma1·itime academy or r;imulator
school program. In any case, training and books can explain the science of
shiphandling, but the art is learned by doing. Hopefully, these maneuvcrs
and this expanded fourth edition of Shiphandling for the Marin r.r ·will
help many mariners become skilled in n10~ing ships.
ACKNOWLEDGMENTS
by Daniel H . MacElrevey
First, I want to thank my son, Captain Daniel E. MacElrevey, an experi
er.ced marher and first-class pilot for the Delaware Bay and River. Dan
provided the inspiration to again update Shiphandling for the Mariner
nnd collaborated on much of the new material. Now, I hope, the boolr.
pusses to new hnnds and another generation of contributors who wilt keep
the material fresh and pertinent to the male , master, or pilot handling
ships.
I am very proud to have a son who is successfully following family tra
dition as mariner, shiphandler, and pilot. AB everyone who enjoys working
on the water already knows, it is more than a profession-it is a rewarding
course through life.
Dan, welcome aboard. For the fifth edition, you will have the conn.
It is a fact that those who spend their life on or around the water are a
special br~ed. They arc a lways willing to help a shipmate and pass on the
seaman's skills from one generation to the next. This is fortunate since no
one person can write on a subject as diverse as shiphandling, and only the
contributions of others make this book possible.
The marine industry has r-rovided much of the background material
nnd most of th e photographs. I am indebted to, and greatly appreciate the
assistance from Texaco Incorporated; Exxon Corporation; Sperry Marine
Systems; LOOP, Incorporated; Raven Industries; Concordia MaritiMe;
Kvaerner Mans; MerweJe Shipyard; the Panama Canal Authority;
Htadink Corp; MnrineSafety International; American Presic'ent Lines;
Seaward International; Blad,
Dean Colver, Willinm Deuton, Car! Din'5ler, Hobiu Erixon, Curt if Ftlzgw
ald, Eugcnc Guest, Bill Lcwis, Douglas Hard, Marsh;.!! Irwin, ',\'ntTUJ
Le back, Gcorge Markham, Jaml"!s F. McNulty, Axe! Munck, Phi l ip Tom let
III, George Quit•k, Georgc Smith, Wilbur Van line, and Albert Wilder con
tributed both ttme and matenal-incplaccable tnformation based upon
years of expcrito supporllhf' master and pilol even though it is impossible for rmc
per.,on to " Prform all tacks inv0lved in maneuvering to th~: berth re
gnnllesr. of how maneuverable the ship might be.
There is :1 direct rela tionship between situational aw:..reness and
safety yet, without a trn lit1onal bddge organization and standurd com
mands for conning, the re is no way hr anyone on the bridg~ la lm..,w wh al
DlHECTIONAl, PROPULSI0!"8Y~TEM~ (j!)
iti bein{! done to maneuvcr the s~ ip . A~ n result, there i:; no way to check for
singlc-pcr~on errors or break the error chain :u; long as the mas ter i:, i ndt
!JI'!'rlently ~::·:i:1b le·, il!ms as any other t ypc ofvt•>;!'C I.
Pilot-Master Relatwnshtp
There is an addi tional consi-ieration wh en discussing the increasi ngly
common but improper one-man operation that efrectively excl udes pilot
control of the navigation and maneuvering of the ship. A state-licen>'ed ,
compulsory pilot is charged by the licensing authority with the duty ro
c \re for the r.afety oftbe vessel, its cargo and crew and, equally importa nt,
with a public responsibility to move the ship from point to point cons is _ nt
with federal and slate laws and port rebrulations 111 a manner that nll ni
mizes risk of collision, oil spills , and environmental damage
Public policy requires the pilot, as a citize, subject to the control and
laws of the host state, to protect the public's interest as well a:i Lo pro\. 1f'
shiph:..ndling and pilotage services to the ship. This reHponsiLiliLy is
clearly c.;tablished by law and precedent and it is inherent in the slalt· p i
lotage system. This aspect of the pilot's role has been reinf(Jrced in an .:·ra
when ships are susceptible la external threats anci use a~ a weapon i;;
modern i-e rrorist-based warfare.
Thl! pi lot must be able to fulfi ll th:tt rc;:pon3ibi:ny b;; ::>.err ~ :1. ;; h :~ ~ ~
her fin al au thori ty to control ship movement in pil ot waters. This is 1wt
possibie if officers at consoles do whatever they f t be standard commands and conning practices so the pi to~
can fulfil: this responsibility to the licensing authority and play his or her
essential role in the pilot -master relationship. (See also chapter 11. )
Lost Shiphandling Sllills
Lastly, ~here is a concern that shiphandling skills traditionally pasl:>ed
from gcnerat10n to generation will be lost s ince Azipod systems allow for
one-man operation with litlle or no involvement or discussion with juuior
officers. Thi t is particularly true when computer-controlled options
with in pradicallimits. T 11erc is, however, a marked increase in the diam
eter oflhe ship's turning circle us the bow comes out ofthe wuter.
t,:FFECT 0F Tltl~l OK I!.ANDLI:>:C CI!All.\CTEH!STICS 71
Fnm1 the !'hi!)hanriler's point of view, a:;,;umini! there 1s not ~s.
Tht:> slf'Cr;n..; cho.rac~eri.· ~ll.s of a .. hif- .m il ..,v•:lt keel ntry ucpcnmng
on the .;hip'8 hull form. A ;;~)'P with a Jar~:,.:! b!ock CC'CllicJCIIL steers poilr]y
tending to be di reclionally unstable. Thi:; conditwn is umplified if the ;;htp
trims hy the head as she enter::; :.hallow water. A :;hip with finer lines may
be directionally $l:tble, or have neutr.tl stability 11 lam on nn even k·~d fhe
behuvior ot a ship with modcr~tc block coetlicient can only lw determined
hy lriaiR s1nce there is insuflicient data available at pn~sent to allow an ac
curate prediction of her steering charach:ristitabl..: for almost ull null
forms. Wlwn in this condition the ship requires large amou!lls of rudder
for excessive periods of time to check her l:>WIIIJ!. The vcsl:>el bcconH'~
cranky and difficult to handle. If she trims by the head in s hallow wut.cr
the problc1:1 is compounded.
Why does a ship behave in this manner when the difictcncc between
the forward and after drafls dccrca!:.es'? One mu::;t look at the immcr::;ed
sections of the ship to better understand thi$ plwnomenon, a ne! especially
at the location of the sections having the maxnnum submerged area.
The shir is turning ns a result of couples formed at. the rudder and
through the center of gravi ty. One oflhe forces forming the latter couple is
1 he imbalance of prc~;;sures about the submerged portions of the hull ( lil:{.
2-10). As thc ship begins turning, there is a new tncrease in p ressure lJt•]ow
the watrlinc on the bow away from the center ofgravtty, th:.ll is, the out
ward bow. This resultant imbalance of forces in thntlocatJon,(orwanl and
oulsidr oft he center of trravity, causes the ship to lx dtreclionally unstable.
All shiJ . .-; cxpericntc the same imbalance in tlw mitial .;~agc,sof a lt:rn.
lf a sh1p is trimmed by the stl,m though, the prcl:>sures ~hi:t. further aft.
along tlH' side of the hull as the ship stabilizes in tlw turn, while the cone·
sponding pressure d rop on the quarter on the inboard side of the turn con
tinues to increase. The resultant couple has then shifted aft. of the ccm"r
of g-.·nvity so the ship becomes directionnlly stable.
Ships trimmed by the head expe1;encc a larger 1nttial positi ve preSSllrc
at the bow due to the increase in submt:!rgea a re:1 iorward, while the nq;a
tivc pressure is reduct•d at the quarter due to thc :·eduction in submcrgt,d
an:a. The couple therefore remains 11head of the center of gravity
throughout. the turn and the s!.ip continues LObe C:irect!onuJlv unstabl•·
G John 11 L'"--------
G
3. Turning at constant rate-ship
:rimrr.ed by head (directionally uMtable).
Fig. 2-10. Effect of trim on steering.
This condition 1s indicated to the shiphandler by the sr.ift forward of
the apparent pivot point of the ship, so the ship seems to pivot aLout a
point nearer the bo\\- than normally expected, and by the ship wanting to
continue to swing after the rudder is placed amidships.
A large VLCC with full seclio.1s forward will experience the same dis- f"
l ribution of presfures in a tu:-n when on an even keel as a finer sh;p does
when trimmed by the hear!. Obvivusly then, if a VLCC is trimmed by the,·~
head. :>he will ht:! even more unsu,b!e since the resultant couple is rnagm
fied accordingly.
The effect. oftrin• by the head on a vessel's steering can be anticipated
by rferring tu the curve of areas of the immersed sections. This cu ··ve is
rlP.veloped hy the naval architect by me&suring on the ship's line drawings
with a planimeter that. portion of the cross-sectional area at each station
EFFECT OF TRIM ON IIAi' Ul.I NG Cl! AltAC.TJ:HJt-: l'll':>
that will be sub111crged at fl particul ar drafi nnd t rim. These :m . .1s a:-e
then put into t.he form of a curve oy measuring ou tward from a ba~ubmertcc~ .u ....... ,\ !'1 c.:1 ~,;l)\ ·
ting th " corresponding poin t at each station, a curvr: is fai red tln uug;, ·he
potnts. The curvp will reach a maximum :..t that station having t.he g! ··at
est submerged arca-,-tbc loccoming in
creasingly important.
Wit.h this in mind, what steps must a mariner take to safely handle a
potentially direclionally unstable ship? First, she must not he ti·immecl by
the head. Keep sufficient drag to ensure that the ship maintains posittve
djrectional fJtability, allowable draft permitl.ing. Seconrl, on a ship wi th
marginal directional stability, the rudder will have to 'le used for a longer
period of time to start the vessel swinging, after which large amounts of
rudder nre needed for longer periods of time than normally expect d to
check a swing. The rudder is put. back nn11dships as soon as the swing be
gins since the rate of turn will increase even when the rudder is a mid
ships. If the rudder is kept on too long the ship will gel away and it mt gh t
not be possible to check her swing in time to av0id leaving the cha n nPI.
Don't o\·erlook the importance of having a trained helmsman whc is ~x
pet·ienced in steering your particular ship A directionally unstable sh1p :-c
quires speral treAtment and the hehnsman's expelienre can bP invah. abil: .
Even this powntiall_y unsatisfactory condition eau be put to adva n tage
if lhe shiphandler watches the s::ecring closely, since n direclionally un
stable ship can turn in a very small area. lt is nut suggested tha t t.he shtp
be purposely loadeJ to obtain this condition, but ol'Len the mariner must
live with a ship "as she is" and in such :1 case he or she can nt least tnkc ad
vantage of the si tuation.
74 SHIPHANDLINC' IN A CHANNEL
MAKING A TURN IN A CHI\NNEL
There Rre two basic consideratior:11 when making a bend or turn in a ch·,n
nel-where to begin the t~rn and how much rurlder to use.
It IS impossible to make a turn properly if the l1.1rn is started at the
wrong place in the channel. Obviously, if the turn is started too late, t!Xces
sive amounts CJfrudder and engine revolutions are necessary lo complete
the turn while remainmg in the clHmnel or in the desired location in an an
chorage. A more common error, though, is to start tho turn too soon, since
it is human n..1ture both to be conservative and to become impatient wh~n
waiting t.> read1 a desired point. This results in havi,...g to check the ship's
swing anJ the'1 start the lurn again ut a later time. Starting a t•1m too
early may not always cau~-te a problem and is certainly preferable to start
ing a turn too !a. le, but if you ha Ye to check the ship's swmg 111 a rhanucl
where suction can be experienced, it may be dlf1icult to start the ship tur.l
ing again once that swing iu Ios~.
Begin the turn when thf:l ship'spwot point is nearly at llw tw11ing point at
lhe end of the reach or range, not the ship's bow or bridge (fig. 2-11). Remem
ber that 1>hips turn circle;>, notcornc>rR. Since you have fixed the diameter and
ndvanco of the turning circle in your mind during the previously descnbcd
trial maneuvers, you should be able to judge when lo start a tw11 (fig. 2-12).
While it is pos~;ible to :Ietermine this point by constructing diagrams
based nn channel widths ~'nd the theoretical turning radius of the ship,
such an approach to a routine mnneuver is not practical and encourages
the mariner to get involved with unworkable methods. It is better to learn
to handle the ship by i.1stinct, and feel developed from experience and trial
maneuvers.
If in doubt uboul thc> a mount of rudder required, use a larger amount
than you feel necel'sary. Reduce the rudder angle as n.:!eded to place t:1e
::-hip at the des;red point in the reach using the reference point method ji,;
cussed m thP next se:;tion. Pract1ce making exact. t.urns at. every opportu
nity. evt!n if a ship is in an open anchorage and there is no need to put the
ship in an exac~ location 'lt that particular time. A professwnal makes
tu;-ps neatly and with a m1nimum of helm orders, and it is only thro•.!gl.
practice lhat the feel for making precise turns can be developed. Turns can
:dso be pra~...tieed with great benefit on a simulator since yr>u can get a very
r·calisti(' feel for both rate of turn and relative movement when wdetermrncd
dur.ng master's rrials.
2. Start turn when pivot
point nearly abeam cunter
of es~matcd turn circle.
3. Ptvot first on buoy H
then on buoy ~ 5
-
Fig. 2-11. Use the pivot. point. to position a ship in a turn.
USING AIDS TO NAVIGATION WHEN TUR:HNG
7fl
.\.r by aligning lhe
buoy with a fixed point on the sl:ip s
- ·-- ~
Fig. 2-13. ?ivoting on a reference point when bming.
77
Using a buoy in this manner is especially efTedive when turning in a
strong current since it is the vessel's movement. relative to the buoy and
chP.nnel (the net movement resulting from the combination of vessel mo
mentum, swir.g, and current effects) that 1s of interest to lt.e shiphandler.
This resultant motion is immediatdy apparent when the ship is turned
using a fued reference. By adjusting the rudder to alter the buoy's rel ative
movement a shiphandler can position the ship in a turn with great accu
racy.
The angle between the lines of buoys marking the port. and staruoard
sides of a channel can be used with great accuracy both to predict t.he
ship's future position in a reach into which she is turuing, and to know
the vessel's position relative to thecenterline after she has steadied up in
that reach. Further, the rate at which a vessel is sliding laterally can be
quickly determined by watching the change in angle of those buoys dur
ing a tun ..
A range can obviously be used to dct.ermine the ship's posiLion relative
to the channel, but do not overlook the fact that the ra~at which a range is
opening O!' closing is of equal importanc~;. This information is uscc! in the
same manner as the change in angle of a line of buoys to position the s hip
in a reach o:- channel.
MEETING ANOTHER VESSEL OR TOW
If a chflnnel is of sufficient width, meeting another vessel is simply a mat
ter of slaying 0:1 your own side. The problem then is one of det.cm1ining
what "sufficient width" is, this being primarily a question "f ship size and
especially of draft and beam.
~.
i''
r.
78 SHIPHANDLING IN A CHANNEL
Ships routinely meet in the 5UO-foot-wide reaches of the Panama Ca
nal with no problems, when the1r combine~ beams t.ot.al up to 170 feet.
(The only exceptions are the Panamax class ve!'leels that do not meet any
sh1p m those 500-foot-wide reaches due to their own inherent handling
limitations.) 'rh is limit. was establisht!d based upon the operating exp~ri
cnc~ of the pilots in that waterwuy and confirmed by simulntor tests ~mu
can serve as a guideline, although ships do meet in channels ofless wirith
than 500 feet under the proper conditions.
As ships approach the 170-foot-combined beam limit it becomes ncceJ
sary to meet in themannershown in figure2-14. In such cases the ships
1. Meet nearly head-on and, when approximate.:y one-and-a-half shin
le:1gth& apart, put their rudders to starboard to move to their own
side and pass safely.
2. When one ship's bow is abeam the bow of the other, her helm is
shifteci to move her stern to starboard until she is parallel to t.he
bank.
3. The rudder is again put to the right to check the swing. Caution is re
quired at this point, so watch the ship's head closely. Your vessel
wants to cr.ntinue swinging due to a combination of the bank suction
on the starhoard quarter and the effects of the other ship us her
quarter comes abeam your bow, that is, your ship wants to turn to
port an her bow paases the other ship's stern. Use sufficient rudder
to check this swing and maintain control despite the effects of suc
tion at the bow and stern.
4. Do not increase the right rudder at this stage, but instead allow your
ship to sag slowly to port so she is heading away from the bank oncP.
again. It is n JW unlikely that you could hit that ship if you tried since
she h11s passed your bow and is moving away. So long as you don't
come together laterally, which is unlikely unless ycu are close
enough to shake hancls with the mate on the bridge cfthe other ship,
you will pa&s safely.
5. Finally, as the stern of the other ship pa,;ses your stern there is a
mutual suction effect that moves your stern away 1rom the near
bank as the two ships pass clear and proceed on their way.
Again, the ship's speed is a key. The ship must be moving at less than
full nwneuvering specJ so suction is rr.inimized and sufficient engine
speed remairs to come ahead and increase the effectiveness ufthe rudder
MEETING ANOTIIEh VESSEL OH TOW 79
------c__,. _j-
-• , .... _-.w •=~-----·-----=-----·-----,..=-..-----,..--... -_.. __
...... _ ................... -=-~ •• ...--····· •.•••.
-----.... I....... .. ............. --.... -........... --~·--o.~-.._..-............. - ....... ~
(-)
~
(+)
-c=:=>-
(-) .. -- - •-... ..... -· ... - ....... _... .... .. ····--·- -- .... __ ··-- . . .. . .. .
(-)
~
(-) (-)
~
_...... --~- ···-- -·- .. - ·-----
....... •-m ..... - -·-=-ea ......... ,.,.....,.. ... ..._. e .......
Fig. 2-14. Meeting in a narrow channel.
80 SIIIPHANDLING IN A CHANNEL
as needed. This passing maneuver is not. au difficult as it might sound, and
is probably C.est. demonstrated in the Houst0n Ship Channel where the pi
lots have perfected what for them is a routine meeting maneuver.
A great deal of study is being done using both simulators and actual
ship trials to determine the limits for safe navigation and meeting h vari
ous types of channels. The resul ts of this research can be used to safely
handle vessels in narrow channels as ship size continues to increase with
out a commensurate increase in channel width and depth.
Hopefully, the practice of using the services of experienced ship
handlers to perform these tests will continue. A great gap still exists be
tween theoretical hydrodynamics and the real world, which limits ti1e
value 0f any tests not performed by competent shiphandle~·s.
OVERTAKING ANOTHER VESSEL OR TOW
The mechanics of handling a ship while overtaking another vessel an~ rou
tine and safe as long ae. the shiphandler realizes that it is the speedat
which the maneuver is pc·rf0rmed that is most import.anl:. If the overtak
ing ship is abenm of the other vessel or tow for any length of time, she in
creases the chances that the overtaken vessel will become unmanageatle,
particularly when her stern is abeam the bow of the vessel being over
taken. Give the overtaken ship as much room as possible and maintain a
moderate speed to minimize the period of time that the two ships are
abeam.
The overtaken vessel reduces her speed as much as possible before the
maneuver begins while still maintaining steerageway, to further reduce
the time required to complete the overtaking maneuver. While being
passed, the clower vessel increases revolutions as needed to increase the
flow past her rudder and maintain steerage.
The Rulell of the Road give the ship or tow being passed the responsibil
ity for agreeing to any passing situation. It is obviouu why this is so. It is
the overtaken vessel that is most likely to have a problem and will ~ the
most likely to go aground should any problem arise. No prudent mariner
agrees to be passed until the maneuver can be performed under conditions
where he or sh~ feels comfortable.
USING SHIPHANDLING INSTRUMENTATION
While the seaman's eye remains the best aid to shiphandling and maneu
vering in channels and restricted waters, other aids are available to sup
plement experien!:ed j~dgment. Radar and other electronic aids such as
USING SHIPH ANDLING 11\STHUME:--/TATION 81
DGPS-bascd navigation S)'sf..ems have b~come increAsingly useful. These
t ools have evolved in accuracy and opera ting features to the point where
they are cqua!ly useful as ofTshorc navigation eql!lpment and aids to p!lots
and mariners moving ships i11 restricted Wdters.
That said, it is a fact that the gyro and fathometnr remain the essential
tools for shiphandling even thol.lgh the nc\' 'er equipment attracts more at
tention. Pilots wisely n!ivigate primarily by eye using the gyro for direc
tional reference and fathometc1 to monito- depth under the keel. The
other instruments have become essential to safe navigation but in no way
do they replace the tools that provide direction a::1d depth.
Navigation tools used by pilots include
1. Gyro
2. Fathometer
3. Radar including ARPA
4. ECDIS
5. Dopp!l.) r Speed Logs
6. Rate-of-Turn Indicatcr
7. DGPS and CTANS
8. VHF
9. Console presentations of wind force and direction aud other pel·f..i
nent operating data
The gyro is used, of course, to maintain qircction, supplying the point
of reference for almost all maneuvers. The gyrocompass also serves as an
accurate audible rate-of-turn indicator as it clicks off the fractions of each
Jegree during a turn. It is surprising how accurately an experienced sea
man can judge the rate oft urn and, of equal importance, whether a desired
or undesire!F.N't',\TION 8:3
e na ble the :~1ariner to detect and control the ship':; rnl of a
degree per ~ccnnc!, althou.:~ dc;;:-c~: jlCr mi:.utc ore used occnsior..:.!!y,
showing a ~atP to the right or left tha t corresponds to the din :ction of t he
movement of the ship's bow. Thi:; iniormation in itself is not of great
value (fig. 2-16J. It is the relative indication that. is import.ant-tha t is,
whether the rat.e is increasing or decreas ing, and by what amount. It is
Fig. 2-16. This fuily integrated bridge includes a hchn s lat.ion
containing gyro rr.pealer, rate-of-turn indicator, a nd all appropriate
steering options sui !.able for ihc ship's s teering system. Courtesy
Maritime Institute of Technology and Graduate Studic».
84 SIIIPHANDLIKG IN A CHANNEL
both interesting And instructive to watch a helmsman do his first trick
aboard a ship fitteci with a rate-of-tu m indicator. After a short time, he be
gins to 3teer bv using th~ !:1dicator. as wellns watt;hing thejackstaffmove
I" cross a point of reference as helmsm!!n have done for centuries. While
holding the ship steady on a compass heading the rudder is us~d to Y.eep a
zero rate of swing. As soon as swing is indicated the helmsman usee suffi
cient rudder to check that swing, often applying the rudder before any
movement of the bow to the right or left can be detected by eye.
When a ship is directionally unstable due to her hull form or trim, the
rate-of-turn indicator becomes essential, making it possible to navigate
restrictad clJannels safely. By accurately knowing the rate of turn the
shiph.lndler can limit that rate to a known safe maximum ar.d always
keep the ship under control. As an example, a current class ofliquefieo
natural gas carriers, which have to be trimmed lu an even keel to meet
the draft requirements of their terminal port, are safely handled in spite
of being directionally unstable at that trim. By limiting their rate of
swing to leso than jf0 of a degree per second it is always possiole to eas
ily check their swing. While the readout is bnsically a relative indica
tion, this rate of turn of 7{0 of a degree per second is comfortable und er
most conditions. A ratE: of turn ofYio of a degree per second is a safe mAx
imum for an ordinary turn, that is, a 36-degree change in heading in 011e
minute.
THE BASICS OF SQUAT
In collabomtion with Larry L . Daggett, Ph.D
and Christopher Hewlett, P.E.
As a ship begins to make way through the water she undergoes a change in
mean draft kr!own as sinkage. This change may occur equally forward and
aft or may be greater at the bow or the stern resulting in~ change in trim
as well as a change in mean draft. The combination ofsinkage anci trim is
called squ11t.
There have been some ;nconsistencies among definitions as usemore detailed infonnation abou!. this
subject, and be::cause from the shiphandler's viewpoint the subject is more
complex than previously thought, 11 few basic, common definitions are pro
vided for the purpose o,fthis text. These definitions would seem useful for
all discussions of squat if the most recent research is accepted.
TilE DASI\S (lF SQ L".;T 85
81 'II.·age is the bodily increase in draft, t~at is, the increase in mean
draft due to the effects of moving in a rcs!ricted channel.
Trim or, more accura tely, dynami.: tnm i:;.th".! ruLation abour. ti1e tr..Jns
versc axis due tc the change in preswre and the rcst:lting change in draft
along t he length of the ship with the f!rca t restricted both '.lr:de;
and 0 11 one or both sides oftl.e huli depending or. the shtp's location in the
channel. The effect of this restriction or "blockage fact.or" is dependent
upon several variables:
1. The speed of the ship thr0ugh the wa ter.
2. Ratio of the ship's draft lo the devth ofwqtur.
86 SIIIPHANDLI NG IN A CHANNEL
3. Ratic of the ship's cross-sectiona l area to the cross-sectional area of
the channel (fig. 2-17).
4. The ship's block coefficient. (The previously expla ined effects on
draft. a nd handling characteristics of a high block coefficien t are am
plified in shallow water. )
5. The ship's displacement, which determines the a1nount of water
that must pass around and uncier the ship's hull at li given s p.:ed.
6 . The rate and period of acceleration as the ship increases speed.
Consider first the effect of ship's speed since this is the factor ovE'r
which the mariner has the greatest control. It has been found, based upon
observat10n s of both actual ships and models, that squat varies in propor
tion to lhe square of t he speed. If ship's speed is doubled, squat increases
~y a factor of four. With today's large ships and minimal unrlerkeel clear
ances it becomes immediately obvious why speed and resulting squat
mus t be verJ much on the shiphandler's mind. It should be noted that the
ship's s;:>eed here refers to the speed of the ship through wa ter a nd no'; the
ground speed s o, if the ship is moving against a current, the speed effe:t
will be increased.
Blockage factor 18 = ~: ~
---I I 11 L.l
I I • •
I I I
' "« I
•••
b
Fig. 2-17. Blo::kage factor in restricted channels.
12
11
10
Till-: DA::ilC:i OF SQL'AT
MAJESTIC MAEnSK ·NORTHBOUND. GAlL LARD CUT
lrrfOl( .. (R1i(A... .., •. S SC""[ C~.i. =r~ I 1 I' ,. ~ 1'
/ "
.,
,' '
_.., ., ..... - '-
~ "' COiiTAINERSHIP, LOA o M5, OEAiol •1061. DRAFT c 317 ' I ~=
\
~ ~ ~E-i-~ ~~= r-~-r
-
- ll r-~-
,_
-~ !-~ j-r-~-~- ~.:!-r-s-. 1-
,.r- :-~.......w& rt
....... ./"w.: ("; i''/' .......... f 11 ' 'D7lu~ .llll."f "H ~ rx.f' ~L ., I"' ..... ,
~-' Ill , l-
UOQ 1100 ""' 1100 11100 7100
etw-NEL STATION (11UIIOREOS OF Fl)
.........
87
7
~ ;;;
! ~
" 3 0
2 ~
l ~
0 d
1~
2 ~
3
Fig. 2-18. This graph show:> the relationship between speed and squal.
Note that the squat (lower lines) incrca:>c~ as the speed (upper line)
increases. This fine h ull conLainership trims ty the stern due to the
effect of squat. Courtesy Waterway Simulation Technology.
The maximum cross-sectional area of the submerged p01tion of lhc
;;hip's hull, as seen by looking at the midships section in the ship's file of
drawings, is significant when compared to the cross-sectional area of a
n 1rrow channel. The ratio oflhese two area~, referred to as the blockage
factor, determines the clearance through which the diRplaced water mu:>t
flow. Obviously, the less area avail able lhc g1·cater the velocity nt which
the water must flow for a given ship's speed-and lhc greater the resul
tant pressu re drop around and under lhe hull.
The other variables li;;ted a lso aff~ct the !l ow !!1 a :>im!lar manner und
their importance will be obvious to the mariner.
The fvrmuia most often used by mariners was c.vnuii;~ted by C. B.
Barrass, Ph.D.' The total squat in open water c3n be calculateJ with suffi
cien t accuracy for a VLCC using lhe formula
7 C. B. Barrass, Ship Squat and Its Calculation, pg. 11.
i
I
88
where
S = squat
SIIIPHANDLING IN A CHANNFL
s (meters) = cb X V2/ 100 or
s (feet) = Ch X V2 /30
c~ = vessel's block coefficient
V = vessel's speed in !mots
Squat in shallow, confined wntcrs is double the quantity S found by the
above formula, that is, in shallow, confined waters the squat equals 2 x S
When aboard a ship with a block coefficient of 0.8 proceeding in Rha l
low water at 10 knots, she will sink approximately 1.6 meters (5.33 feet). l f
the speed is teduced by half, to 5 knots, the same vessel sinkR only 0.4
meters (1..'3 feet) or one quarter the squat experienced at the higher speed.
It should be noted that this formula for predictiPg squat generally over
estimates the squat and thus provides a margin of safety. In some caser
where this formula has been compared to measured squat, the margin of
safety was found to be too large for practical operations. In those cases,
other predictive formulas hav~ been found to fit measured squat more ac
curately when a more accurate prediction of squat is required. Many of the
available predictive models are described in a PIANC publication•.
Recent measu;.·ements of ship squat using high-accuracy differential
GPS equipment have shown that the most accurate predictive model is de
pendent on the ship type and waterway characteristics. For example,
measurements of twenty-six ships on the St. Lawrence Seaway' demcn
strated that squat could be predicted with mean errors of0.08 meters vr
less and standard deviations of less than 0.13 meters using formulas sug
gested by Tuck, Eryuzlu et al., Barrass, and Tothill, depending on the ship
type and whether thE' transit was in a canal or lake. However, Tuck was of
ten nearly ns good for predicting squat as an estimate made using the
"best fit" technique. Recent measurements demonstrated that the pred!c-
~ .-\ppr-.Jacn Chanr:eis: A Gui-de for Desigr.. Appendix C, F1nal rep('lrL of the JOintworking group PIANC and IAPH, in cooperation with IMPA and !ALA,
published 8!. a supplement to Bulletin 95, June 1997.
s Larry L. Daggett, J . C. Hewlett, Devid Stocks, Maximization of Ship Draft in
the St. Lawrenc:P.. \'olume I, Squat Study, Fleet Technology Lim ited and
Waterway Simulation Tecl.nolor,y, Inc., Transport Canada TP 13888E,
December 2001. '
1'111~ BASICS OF SQUAT 89
tivc m tcrs and a standard deviation of 0.07 1neters for a VLCC in the De l a·
warP ;1ay Rnd River.
Co"1parison ofpredir.ted and measured squa t in the PC studies has yet
to be conducted or. u vessel-type basis or on u fully combined datnb.1sc;
however, comparisons for individual ships ha ve yielded some useful re
sults. After generating comparisons for S\!Yera l of the aforementioned
published numerical methods, three fonnulatiom. were found to prov-ide
the best. agreement with the measured data from the Gaillard Cul.
That said, it is obvious that there is no single bel>t formula for a ll condi
tions and the I3arrass formub does, as stated earlier, consistently provide
an important margin of safety.
The I3arrass formula has been discussed. The two other formu las refer
enced are
1\Jck/lluuska:
S, = bow sinkage in meters
V = ship volumct.ric displacement in meters'
L, = ship length between perpendiculars in meter!'
K5 = 7.45S, + 0. 76 forS, "> 0.03
K, = 1 forS, :;; 0.03
where S, = A5 /AciK.;
A, = ship underwater cross-sectional area
A, = cross-sectional channel area
K, = l Channel-type parameter for canal wi th no O\'crbanks
F .• = Froude number based on t.he undisturbed wat.cr
depth = V/(gh)"
where \ · = ship speed through the water in rn/s
g = acceleration of gravity in m'/s
h = water depth in met.ers
Eryuzlu and H.1usscr:
7' = ship dra ft ; B = ship beam
90 ~HIPHANDLING IN A CHANNEL
For fdly loaded tankers in unrestricted shallow water: 1.08 Wy
Simulation Technology, Inc./l'nnama Canal Au thori ty.
92 SHIPHANDLING IN A CHANNEL
UNDERKEELCLEARANCE
The squat phenomena, as discussed to this point, has been well known and
understood for many year~ to the extent it affects a single ship and so fa ..
as ship's draft changes for a given channel configurati0n, hull form, and
speed through the water. Additional discussion is needed of factors Jther
·than squat that affect underkeel clearancl:l as larger ships load to greater
drafts. Ports and channels that once were considt:red suitable for deep
draft ships are now margi11al as larger ships load to deeper drafts and un
derkeel clearance is reduced to the minimum corrsidered safe for the port.
In the past, some research was done to predict squat and underkeel
clearance under more complex conditions such as when multiple ships
pass in narrow channels but the findings and accuracy of the data W'lS
questionable. Much of the research was conducted in test tanks so practi
cal consideraLions including the impact of ship stability, changes during
periods of acceleration, and effects of ship interaction on squat w~re rarely
applicabk to day-to-day maneuvers in shallow water.
More advanced tests have been conducted in th_ past decade using sur
vey grade DGPS to measure changes in draft and trim of ships underway
in narrow channels under dynamic conditions. These tests have focused
on under keel clearance (UKC), which is the primary concern for mariners
handling ships in shallow water and narrow channels.In the past,
shiphandlers often considered squat and UKC as basically synonymous
although they arc actually something quite different and that difference is
increasingly important as more ships arrive at a port loaded to the maxi
mum safe draft. In fact, factors including acceleration, ship/ship interac
tion, and rollinG in turns are at least as important as squat in any
discussion on undP.rkeet clearance. All factors are dynamic since ship
speed, stability, hull co11figuration, and channel profiles are interrelated
and a change of .any one of those factors affects UKC. Mariners and pilots
tend to focus on squat when they discuss UKC but these other factors were
found to be at least as important when navigating in some areas of the
Panama Canal and other watenvays (fig. 2-20).
De.fnitiva tes':s were conducted by Waterway Simulation Technoiogy,
Inc. (WST: for the Panama Can11l Commission (PCC) in 199R when
drought conclitiom> made draft and squat critical.10
" " This landmark
lO Larry L. Daggett , Ph.D., P.E., and J . Christ.opher Hewlett, P.E. Study of
Ship Squat w tl·e Panama Canal, Waterway Simulation Technology, Inc. for
the Panama Canal Commission, Balboa, Republic of Panama, March 20, 1998.
UNOEHKEEL CLEAR.A.'\C~ 93
Fig. 2-20. All the efTects expected in a confined channel can be ~n in
the Gaillnrd Cut..
work, because of its scope, expands significantly on past theory regarding
squa t and UKC requirements in shallow water. The opportunity to mea
sure thes.t and chang:'ls in UKC as ships meet a nd pass m n a r row
channels, accelerate in shallow water. turn and roll in twisting channels,
and mo\·e between areas with varying and irregular channfll cross sec
tiuns. Tu that txt.ent, the Panama Canal teds provide grea ter knowledge
of hydrodynamics affectmg squ at and draft that must be disseminated to
the industrY.
Similar .tests conducted in other waterways including the St. Lav.:
rence Seaway , Houston Ship ChJnnel, a nd Delaware Bay a nd ~ive: ven
fied the resul ts of the Wawrway Simulation Technology stud1es m the
.j
l
UNO EH KEEL CLEARANCE 95
PanamJ Canal; huwever, it was fow1d that specific predictive formulas for
particular :;hip t.ypes end channel characieristics provide more accurate
estimates of squo ~ thon "he 13an-«.;.; funnuiu. Buseo on thesP. waterv.·ay
spct:i fi.c mensurer.;ents, the predictive model, and updated channel survey
data, a UKC calculator can be developed tor use in analyzing UKC fur a
planned transit.
To summarize t.est findings, it was confirmed that
1. Speed through the water is t.he most critical faclor when determin
ing and maximizing UKC.
2. Squat increases for a g1ven block coc fficicnt. a:=: speed mcrcascs, with
the increase in squat being greater for ships with higher block coeffi
cients.
3. The rolling effect for various sLip types turning in narrow channels
is significant and, for wide-beam ships where draft increases signifi
cantly for each degree of roll, may limit UKC more than squat a t
lower speeds. This is especially true for containerships since they
somet.imes discharge water ballast to rerluce draft in restricted
channels and thus have a lower GM.
4. In general, ship type is a factor when predicting changes in UKC in
narrow channels.
5. Squat may be as much as double the calculated squat. for constant
speeds when high-power ships accelerate from a st.o1) or increase
speed quickly.
6. The effect of"crabbing" due to bank suction that causes a ship to pro
ceed at some angle to the axis of the channel does not. seem to in
crease squat although more research is required in th is a rea.
7. Squat varies as ships pass through channels with changi ng symme
try as the blockage factor changes.
8. Squat generally increases 50% as two ships pass ir. a t::hannel or
oth e:- rest!·lcted area but can increase by as much as 100% depend
ing on the ships approach speed and !;eparal.ion distance.
Safe Speed for Minimum Under keel Clearance
The PCC squa t sr.udy verifi ed the classic principles for calculating squat.
The change in squat is geometric. Basically, for the same conditions,
squat varies approximately as the square of the speed. Double the speed
and you increase squat by a factor of four. This is especially imponant in
\
96 SHIPHA."'OLING IN A CHANNEL
shallow water where the tests den10nstrute that, as a rule of thu n1b, 6
knots is a practrcal speed limit for shrps in channels where UKC is 5 feet
or less considerinl! variables lm"b as acceleration Pnd rolling in turns in
addition to squat effects. Of course, good sel\manship should prevail llt
all timo>s .
The shiphandlcr will always cvnsider factors such as a rocky vs. mud
bottom, the qualityof charts and accuracy of ranges and buoys, the type of
ship, its stability, and other factors that affect concerns with grounding in
a particular area. They may routinely navigate a channel with a mud bot
tom at a higher speed. At the same time, they may proceed at a slower
speed to have greater clearance when the bottom is rocky. Pilots make
these adjustments routinely and often proceed at higher speeds because of
their local knowledge of channel symmetry and bottom type that permit
higher speed a with safety. This is the essence ofpiloting and the reason pi
lotage and local knowledge are irrepleceable in the safe handling of ship..>
regardless of o::hanging technology.
In any case, absent specific local knowledge tfl the contrary, the
6-knot speed limit for 5 feet of UKC is a useful rule of thumb for
shiphandlers that is suitable for safe navigation in almost all
conditions.
Effects of Stability on UKC
There is an apparent contradiction between points 2 and 3 (on the previ
ous page) as demonstrated by the DGPS measurements. Ordinarily,
wide-beam, full-hull ships such as tankers and bulk carriers arc expected
to experience greater increases in draft because squat is greater for ships
with a greate;.- block coefficient. Those ships would ordinarily require a
greater UKC for a given speed. In fact, at slow speeds, wide-beam ships
with finer hulls may require greater UKC because GM is less anJ they will
roll more for a given speed than the ship with large block coefficient. For
example. the deep Jraft of a 106-foot beam Panama;,: ship increa5e5 ap
proximately 11 inches for every degree of roll.
The reality when considering changes in UKC for various ship types ir.
often different from what might initially be anticipatd. Bulk carrier:; and
tankers usually have larger block coefficients (above 0.8), less horsepower
(6,000-14,000), and greater .>tability (GM more than 3 feet). Tl-.ey are
more likely to squat by the head and accelerate more slowly." Due to higll
UNDERKEEL CLEwith
findings, this low block coefficient vessel trimmed by the stern due to
squat. Courtesy Waterway Simulation 1'echnology, Inc./Panama
Canal Authority.
carrier/tanker t_ype vessels than contninership!.. Increased hcc! was also a
primary factor for changes in the vertical for lypic&l cont.ninC;rships in
meeting situations (fig. 2-21).
Shiphandlers must not underest.imat.c t.he ciTcct of this ship/ship inter
action on squat and draft. The increase cnn be drastic and rapid so ships
moving at high speeds in narrow channels could ground immediately as
tlley meet. It is noteworthy that a 900-foo~ cont.amership rraveling at 11
knots in an otherwise safE.- ?Or)-foot channclmuncd: ::.t''l~! ;.,t::r!!ascd dra~
by more than 7 feet as the ships passed."
14 Ib:d, Pb· 41.
100 SHIPHANDLING IN A CHANNEL
Overtaking
One would expect that squat would be greater for two vessels in an over
taking r.ituation thflP. for a single vesse! in the channel. One WO\:.lrl also ex
pect squat to be greater for two vessels in an overtaking situation than for
two vessels whr:n meeting and passing and the increase would last l.:mger
since the ship/ship interaction con.tinues for a longer period due to the
lower speed differential between overtaking ships.
There is a lack of data on this situation so it is not possible at this time
to say with any certainty that this assumption is correct. For safety rea
sons and until there is data available to support or refute that assump
tion, it seems proper for shiphandlers to assurr!.e the increase in draft
when ships overtake in a narrow channel is the same or greater as when
ships meet and that it lasts for a longer period.
Squat, underker:l clearance, ship stability, speed, hull f(Jrm, channel
form, and all the other factors discussed in this sect.ion could cause a shi)J
to ground in an otherwise safe channel. Also, in addition to grounding, re
cent research clearly shows the importance of considering all factors a:
fecting Jteering and shiphandling in narrow and shallow channds.
STOPPING AND MANEUVERING IN A C!{A.NNEL
The berth ia I'OW in sight but the tugs aren't yet available, so it is neces
sary to stop your ship during her passage up the channel and hold her in
that location until tugs arrive. It would of course have been better to have
had the tugs made fast before needing to stop, but it is certainly not a prob
lem to stop without them. The maneuver for stopping your ship whilf'l
maintaining her heading is discussed in the section on master's trials in
chapter 1, and since you have kept the ship's speed moderate at all times,
you are in control of the situation with or without tugs.
The experience gained Juring the master's trials helps you judge
whether the ship eau be stopped in the distance available using only rou
tine maneuvers. Remember that it is often possible to perform two or morC'
maneu\'ers simultaneously , such as using the tAndency for the bow t.o
swing to starboard when the engine is put astern to both make a turn to
the right and reduce headway.
CHAPTER THREE
USE OF TUGS
We mancuverea in the outer harbor w1til it was dark.
When we put in the Chief came to the b:-idgc, wiping his
hands with a wad of cotton waste and his forehead with
his sleeve. "Blimey, Skipper," he said, "you certainly
kept us busy." I had ... ; found out that she wns indeed
a lovely ship; you couldn't expcc : her to do more and H ill
be caiJed a tugboat.
--Jan de Hanog, nu: ui.stant Shore
The heavily bearded docking master burst through the wheelhouse door,
grabbed the old man's hand, and welcomed him to the port in a voice tu:o
tones deeper than our whistle. Taking the radio in hand, he instructed the
two tugs that would be assisting us to the dock to come alongside and make
up.
How do you like your coffee, Cap'?"
"Black please. Just blach an.d hot will be fine," the docking master re
plied to the captain.
"Call the stand by and hauc him bring up a pot of coffee, Cadet."
"I'll get it, sir. It will only take me a ser.ond to go downstairs for it, " re·
plied the cadet.
1'he dochirtg master glowered at the cadet, but said •wthing until he had
left the wheelhouse. Obviousl.Y, he didn't lil:e the young man's reply.
"Downstairs! Downstairs! Where the hell does that kid think he is," bl'l
~owed the he.·etofore jouial docking pilot.
"They don't go down below anymore, they go downstairs. Dcchs art
/Z?ors, lines are ropes, and the other day one of these hids called a moonnJ
lectured on that subject for the rest of the docking.
Unfortunately, it is true that the vocabular.J of the manner is often 1g·
nored end those who have been working around ships for any length of tune
arc nvt h·
ward, and produced hj•, these neophy!e admirals who do not unden;fond
that the language of the sea is steeped in tradition. Nautical vocabulary al
lows those aboard ship to comnumicat2 orders and ideas clearly and co11·
cisely w a manner that is not open to misinterpretation. For this reason i f is
important that the shiphandler use proper and accepted shipboard termi
nology when giuir~g orders.
While practitioners in the medical, legal, engineering, and scientific
fields haue and use a specialized vocabulary peculiar to their professio:l,
the language of the sea is now being misused with regularity. This is sad
since seafaring is not just a job, it is a way of life, and the seaman's vocabu·
lary captures the very essence and epirit of life on the water.
The arJument has been made by some that the seafarer should "mod·
emize" nautical language so it could be immediately understood by all,
even though this would actually mean that it would be clearly understood
by no one. Without a unique nautical vocabulary it would be impossible to
accuratel:>' express ideas or describe conditions in the marine environment.
A whole series of long and ambiguous sentences would be needed to express
the same thoughts that the seaman can now convey with but a few words.
Consider the paragraph of instructions that would have to be given to a sea
man tending the spring line to get the same reaction that the mariner get8
from the three words: MCheck the spring. n
Just as doctors or lawyers would not bastardize the language of tlwir
professions, nor tolera.te others in their field who do not master ~hat lan
guage, neither should the mariner accept the misuse of the language of the
sea. It is another aspect of professionalism.
After being properly chastised the cadet went forward to assist in the
docking, having assured the docking master that his point had been made.
The work of the tugmasier is a subject unto itself, and it is beyond the
scope of thie tex t to discuss that work. Only the use of tugs to ~ssist in the
movement and berthing of ships will be covered here (fig. 3· 1 ,,
There a re several types of tugs, each of which has its limita~ions a r.d
advantages. The single-screw harbor tug is still predominant in many
ports and will serve as the basis for this chapter. It's essential that the
shiphandler understand the tug's work, anu her linlitations and capabili
ties, so that he can do the best possible job without endangerbg the assist
ing boats.
MAltugs fast and gets ready to go alongside.
The tugs cnn be made fast in several ways depending on where they arc to
be placed and t:1e work that they arc going to do.
If the tug is to assist in a routine docking or undocking and is t,o be
made fas t on the bow or q uartcr, she generally pu..s up two lines. The fl.rst
line sent aboard, to be led forward and put on a bitt on the ship's deck, is
the backing line. This line is made fast to a bitt on the tug's foredeck. Since
this line will take a heavy strain as the tug backs against it t,o pull the bow
or stern, it must be put on a bitt aboard the ~hip. Too often, the mate on the
bow or stern puts the backing line on a small cleat on the bulwark, or on
some other unsuitable fitting that is out of the tug masLcr's I int~ion without losing lllfective
ness and to work at more than one location around the bow or stern with
out having to shift lines.
COMMUNICATING WITH f. TUG
WhilLe tulle, Kings Point classmate and Philadclphi:llawycr, gave some ordt r
to the chapter on the master/pilot relationship.
Contributors to this edition include these same "shipmates" pl us La rr:.
L. Daggett, Ph.D., and J. Christopher Hcwlctt, P.E.; Captain Paul lvPs,
Capta in \Villiam McAuliiTe, and RTM STAll Centcr stafT Brian Long nnd
Captain Joseph Lobo.
Lnrry Daggctt and Chris Hewlett are principals and of1lcers of Water
SimulatiOn Technology, Inc., a lcade1· in the study of squat, sh ip behavior,
and the cakulalion of underked clearance for shtps in narrow channels.
They have completed in-depth studies on this subject for the Panama Ca
nal, St. Lawrence Seaway, Delaware Uay and River, Hcu~lon Shi;J Canal,
and Plsewlwre. The techniques developed by WST have made it p"ssiblc ~o
stud:v this important area of ship b:havior wtth ~rre2~e!· :!r:::;rn::y ba.~rcl 0n
1 he performance of uclual ships in real-life operating conditions in mnr ..
depth lhun ever done before. Their contributions t.o the section on squat it•
this text will interest every practicinrr mari:JCr rnd sltiphand . .: r , and tll'~
seafaring conrmunity apprcciat.cs theirwillintrne.;s to shan• that re se: re h.
Captain Paul h·cs is n retired Delawa re Hi·;er and Bay pi lot. J!P is '1
past. prt>Hidcnt of th at a~socintion and has been a respected vPicc for pi lot~
XVI ACKNOWLEDGMENTS
for half o ce11tury as a consistent adw1cf.ie of applied technology for )>ilot
ing. Paul l"riiRs on bridge resource management and shiphandling for
J':as lert:~ nnc.J pilot!>, u'ld hP t.eakill:;. It is a skill both H"
old as the fi r!il~hip and as new as the latest vessel to be launched, yet little
wrillcn material is 'enlial for the ma!itcr to
be able to judge whether a pilot's actions arc proper und whether the slup
1s being handled in u safe manner. While it certainly is not possiblP for the
seaman to read this short book and then do the wor!· of a pilot wlw ha::
spent years refining shiphandling skills, the book will at least hclp IJlari
ners to better understand the handling of ships.
Until recently, little significant stuuy was done on the behav1ur of
large shi ps in shallow water. The science ofhydrodynamics is now hcing
appl ied to shiphandling and much is being learued that wtll allow the
seaman to better predict a ship's behavior. Ships do respond in a pred ict
able manner to the forces 01'wind, sea, a nd current, so these 3tudic:; arc
i m portu nl.
Y~>ars of exper·ience arc needed before the shiphandlcr can put thi;:; m
formation mto a "'real world" pers pective. So many variabl e~ and so
many lcarneJ techniques are involved when actually handling ,-hips
that shiphandling remains more art than sciencl!"-nnd this book's non
m athematical presPnw tion, stressing application over theory, rcf1eincere effort hn:-: been made lo separate fact from fiction nnd all thnt
is contained herein is based upon actual experiences of practicing pilot.
nnd professional mariners. There arc too many myths aboul shiphr.n
dling, especial !) ;n the use of anchors and the behavior of ships in narrow
channels, and where Lh"s \'Olume diflers from commonly held opinio:1
those differences arc based upon the experiences of mariners who have
performed sucl, evolutions hundreds of limes. Il is ttme to ,·cplace the
myihs, horn ll!Ore of an overuclive imagination than of experience, with
fncts that 3re applic>lhle to today's ships and conditions. Further, this te:;t
ts written for lne r-·ractici ng mariner who already possesses some de14fee of
professionai knowledge, expPrience, and training :n navigation and sea
manship.
Mntetiallhd is not original has been credited toils sow·ce but the bulk
qf this information has been glenned from lhe community of seamen and
has been passeJ along from master to male, pilot lo apprentice. Il is not
po:;sible to creJit lhat informa_ion to any single source. The assistance of
the many mariners and pilots who reviewed this material is appreriat.ed
nnd the unselfi3h mannrr in which they donated both their lime and PX
perlisP i!' inciicalive of •vhat makes the :ommunily of lhe s"n different
from that of oth~r profer.sions.
Just as a voyage is o natural progression of events from departure to fi
nal arrival at a pot L of destination, so too is this book organized to follow a
vessel and her 0fficers from the lime she is preparing for arrival until she
is again bark at sea. This should pullhe information into a l0gical 01 der.
After following that hypothetical passage to its conclusion, spe.:ial evolu
tions that are not often encountered by the mariner are described in the
nmcluding chapters. Sinre it is inevital.le that such a list of evolutions wtll
he incomplet.J, it t!l hoped that others in the maritime profesFion will put
u:;ide lhl' ir coffee cups anti add to this collection; as professionals we would
,,ll appreciate t:1e opportuni ty lo learn from their experiences. It is t1me
that moro is writtby a tug that is acting in the desired dire-;tion under a
given situati cn, but in th{: real world it is sufficient to know that the tug is
USING A 1'UG 107
in fact having more t!1an one cfTect and to use these efTccts to your be~t ad
vantage (fig. 3-3).
Oth~r than the pushing and pulling .:!:Tect;; on Lh~ ;;hip's bow, th~ ; ) 'lW
tug can als\l be used to fvllow a ship which is going astern, working stem to
stem to Etecr the ship by pushing on either bow as required. The tug tralli
thP. stem and comes ahead against the port bow to move the stem to star
board and thus turn the ship to port. Pushing on the starboard bow has tho::
opposite effect.
The. bow tug is used to hold the ship alongside in position aft.er arriving
at. the berth until mooring lines are out. and tight. By keeping the tug at
some angle to the ship, that ship can be held against a flooding or cbbmg
current as well as alongside her berth until she is secure. Other uses of the
bow t.ug arc covered in sections on approaching lhc berth in chapter 4, o nd
going alongside in chapter 5.
Fig. 3-3. A tug's force afTects both the ship's lateral motion and her
headway.
I
I
\
I
108 USE OF TUGS
The after tug or stern tug, if placed on the quarter, is made fast in the
same manner as a tug on the bow, that is, with a backing line and a come
El head line. The tug backs and pushes against the hull in the samP. manner
and with the same effects as the bow tug, with two important differences:
1. The after tug acts as a drag, reducing the effectiveness of the rudder,
especially at slow speeds when the shiphandler is trying to move the
stern laterally without any significant increase in speed.
2. The stern tug tends to set the stern away from the side on which she
is made fast, \.Oward the pier or wharf in a docking situation, which
creates an additional problem for the shiphandler. This effect in
creases as the angle at which the tug lies to the nhip increases, since
thP. tug is acting as a rudder of the dimensions of the tug's underwa
ter profile (fig. 3-4).
For tht!se reasons it is best to have the stern tug stand ofT until actually
needed io assist the ship, and to be let go after undocking at the earliest
practical time.
Occasionally a tug will be secured on each bow when the ship is ap
proaching a be1th or lock, or holding a position in a channel (fig. 3-5). Ei-
0
0
_...Q_ 0
Sh ;>'s stem ~.d,
as the tugs back against the ship's he~dway. The ship's engine can also be
used as required, so tha t she is both steered and s tpped with maximum
control.
A tug can be placed astern of the ship and made fas t with one or two
lines (fig. 3-6). In this position the tug backs to slow the ship or comes
ahead to either the right or left to move the stern, acting much like an ac
tive rudder to supplement the ship's own rudder. The tug can also be used
to steer without the ship's engine, controlling the ship wilhou~ developing
excessive hEadway. It is claimed in some shiphandling texts, and occa
s ionally by pilot3 in ports t~at. do not normally use tugs in t.his manner,
that there is some hazard to a lug made fast on the stern. This is simply
untrue. For example, tugs have been used asiem to assist literally thou
sands of ships through the Gaill ard Cut in the Panama Canal at speeds ,,f
~to 8 knots without any problems. Often texts recommend using a Lug on a
h awser ahead of the ship to :1ssisl th e ship to steer This urreffective to back the tug to turn the ship
to th~ side on which the tug is lashed up, that is, back a tug lashed to the
port quarter to turn the ship to the left (stern to :ight. bow and ship to the
left). Once it has headway a small ship can be moved efficiently w1th only
one tug lashed up.
The other common type of lash-up places the tug on the ship's bow
hP.ading aft. 'l'llis might be done when only one tug is used to back a shi p
from a berth around another ship docked astern or to back a dead shiF
from a b&rih. After being lashed up (fig. 3-8), the tug is backed to move the
ship's ntern off the dock to get clear of the berth and around any ship
astern. When the ship has sufficient angle to the berth, the tug comes
ahead as needed to steer the ship from the berth. rlelm orders are used.
that are similar to those used to move the ship from a berth under her own
power .
When leaving the berth stern first, left rudder is used by the tug- to
move the ship's bow tu port and thus her stern to starboard. This can be
confusing, so face aft in the direction in which the ship is moving, and give
helm orders to the tug. 'fhe maneuver is immediately simplified and the
helm orders nP.eded are obvious. Once clear of the berth, with stern way on
the s hip, the tug is given a course or steadied on a heading and the tug
master steer s "he vessel much as a helmsman would.
A ship with a tug lashed •.1p can be stopped by backing the tug. Ifthe tug
is lashed up on the starboard quarter when moving ahead, or lash ed up on
tho port bow when moving stern first, the ship will twist and can be han
dled like a s ingle-screw chip with a righ~-handed propeller.
A lashec-11p tug can ofl.cn do the work of two tugs when used together
with the ship's engine moving a ship laterally without developin~
l.ASII ING UP A TUG
Tug lashed up lo
take ship stern hrst
from a bcnh.
1. Tug backs against
spring to lift ship's
stern off tho dock.
2. Tug comes ahead, rudder
hard left, to lift the
ship's bow off the dock.
3. Tug's engine and rudder used
to steer ship from berth.
Fig. 3-8. Undocking with a lashcd-u~ tug.
Ship's eng,ne ahead,
rudeler hard nght.
• !
Tup ahead. rudder
hard left.
Fig. 3-9. Working tug nnd ship in opposition to move ship laterally.
113
\
I
I
114 USE OF Ti.JGS
headway. Uue of a tug in this manner requires close cooperation between
the shiphandle:- and tug master, as well as a good tight lash-up. The tug
lashes up at the bow heading aft. She comes ahead with her rudcler hard
over in the dh·ection of the pier while the ship uses her engine ahead and
rudder hard over, also in the direction of the berlh. The ship'~:~ bow and
stern then move together away from the berth, the ship's engine working
in opposition to the tug so the ship gabs no way ahead or astern (fig. 3-9).
I,
CHAPTER FOUR
APPROACHING THE BERTH
• l
There are many old pilots, and many fast pilots, but
there arc few old, lttsf, pilots.
-Traditional
The docking master hadn't left the center window of the wheelhouse :;ince
beginning the approach to the pier. He continued to give helm orders slowly
and quietly, signaling with his hands to the right or left as he gave the rud
der commands to the helmsman. With a strong northwesterly breeze setting
us toward the docll it certainly was not going to be a routine doching and yet
he showed no signs of tension or concern. /(the clochi:tg master's demeanc>r
was any indication, the docking apparently was not going to be as difficult
as those of us on the bridge had expected.
As the ship came up to the _'Jier the doclling master walked out on the
bridge wing where he stayed until we were in position alongside the berth .
E ven when the bow fell off the wind toward the berth the orders ea me slowly
and delibemtely, and if the docking master had any apprehension about
the evolution it never showed. Doching on this blustery a(temoou was un
eventful-about as exciting as watching grass grow- just the way it was
supposed to be.
GOOD BRIDGE PRACTICES
Several important aspects of the shiphandler's work have been touched
upon here, all of which are as important as the technical skills involved in
docking a ship.
1. The docking master did not move about l,he bridlie whi!~: working.
2. Hand signals were given to clarify all helm orders.
3. The pilfJl remained calm and unexcited throughout the docking.
Select one location to work from when hanriling a ship and don'l move
from the position until nearly alongside. Too oflen the shiphandler v. ill
move from wing lo wing and back again to lhe wheelhouse ala frantic pace
115
\
116 APP'ItOACHING TH E DERTH
that increaseR as the ship gets closer to t he dock. Ostensibly, th is is done
so it is possible to get an unobst ructed view of the a pproach but, in fact, i~
onlv mak es it very difficult to appreciate distance, speed, and motion. The
ship's heading is immediately obvious from &ny vantage point, but less ob
vious is her rr.otion bot.h ahead and athwartships. It is important that the
shiphan dler pick one location, generally amidships , and stay there until
close to the dock. When nearly alongside, when cargo and superstructure
block the shiphandler's view, a move can be made to the bridge wing where
the shiphandler should remain until the docking is completed.
Helm orders must be supplemented by hand signals to right and left to
avoid any misunderstanding due to la nguage differences or ina ttention. It
is quite common, especially during a long passage, for a helmsman to re
peat an order correctly and then put the wheel in the opposite direction . If
the shiphandier points in the desired direction when the order is given,
this mistake is rarely made by the helmsmar ..
The pilot's manner of working ensures that a calm and orderly atmo
sphere prevails throughout the docking. Often, if a mistake in judgment
or action occurs, it is because people become excited-and excitement is
contagious. Even when a problem rlevelops, ifthe shiphandler , be he pilot,
master , or deck officer controls emotions so his concerns are not obvious to
others, there will be none of the shouting and running about that only
Fig. 4-1. "He's planning the docking .. . says sh iphandling is an art."
DISCUSSING DOCIUNG PLANS 117
complicates e bad situation. The shiphandler controis the mood of the
bridge. as well as the movement of the sh1p.
DISCUSSING DOCKlNG PLANS
Discuss the approach and docking plans well Lcfore reaching the berth.
The docking master appreciates the opportunity to brief you and to be as
sured that the ship and crew a re ready to respond as required. Don't ex
pect him to predict each bell and helm order in detail but do get an
understanding of:
1. The approach, including any special maneuvers or engine require
men ts.
2. The placement of tugs.
3. The configuration ofthe berth, including any special problems such
as poorly located dolphins , ships to be maneuvered around or be
tween, and any unusual space restrictions. This is the time to learn
of potential problems and to cancel the dockinr. if you don't feel it can
be done safely. Don't wait until the ship is halfway up the slip and
being set down on the vessel in the berth astern.
4. Any special requirements such as a need for the anchor or for any
unusual leads for the moor!ng lines.
5. The current and wind to beexpedcd at the ber th. This is oflen differ
ent from tha t indicated in the cmTent tables and can best be ascer
tained from the docking master who has the locallmowlcdge required
to make accurate predictions.
In turn be sure to give all the same information to the docking pilot that
is described in chapter 1 for the channel pilot. Too often the docking master
is not properly briefed since the "passage is almost over." It's at least as im
portant tha t the dockingmasterbc as fully informed as the channel pilots.
Don't hand tr.e docking n:oster atwo-page preprinted forn, o.sking for a
detailed description of the "docking plan," including the engine bells that
will be required and the heading of the approach. The docking master can
not do th is, nor would you want to restrict him to ru1y such predicted set of
man euvers. Such forms and procedures only refl ect the Jack of profes
sional background of the originating pa r ty, and create an embarrassing
sit.uation for both the master and the pilot who mC~St dal wi th such absur
dities. An intelligent discussion between two professionals to ascertain
the general plan for the docking will suflice.
118 APPROACIIING THE BERTH
If you don't agree with the propoRed plan, let the docking master kPow
about it. Don't wait until the middle of the evolution.
TIMING ARRIVAL--HOLDING IN A CHANNEL
For a number of reasons it may be necessary t c plan a vessel's passage to
arrive at a berth, turning basin, or lock at a specified time. The master or
pilot may wish to dock at slack water, or the tugs or berth may not be avail
able until a particular time. This is a routine navigational problem.
When timing arrivals, the mnriner often attempts to arrive exactly as
scheduled and allows no time for unforeseen delays. Any reluctance to ar
rive early and have to maneuver the ship to hold her in position in a chan
nel for some period of time is natural but unnecessary. The ship can easily
take an hour to go the last mile to a desired point so there is no reason not
to allow some extra time when planning a passage.
The master or pilot can
1. Anchor to a short scope of chain with a head tide.
2. Steam on an anchor at slow enlji.ne speeds and hold a positi on and
hea.ding in the channel even if there is a moderate wind from abeam.
3. Hold wit.h a tug on each bow, using the engine as needed while the
tugs minimize headway.
4. Back and fill as necessary with surprisingly little advance up a
channel.
Further, by arriving early the master has an opportunity to practice
any or all of these maneuvers to sharpen shiphand:;ng skills and develoo
confidence. Arriving early presents no problems but arriving late causes
the mariner t..o use excessive speed-the shiphandler's worst enemy.
SPEE~ OF APPROACH
The me.jor difference between the neophyte and the experienced ship
handler is the speed at v. hich they work. The less experienced shiphaudler
generally works too fast. Don't equate increased speed with increased ability.
When beginning an appr0ach to a berth, spe~d should be reduced to
bare steerageway. This is much slower than most mariners realize and it
is a rare ship that, under calm conditions, will not steer at speeds of le:;s
than 2 know if given a chance to respond to her rudder. Further, by using
the engine in bhort burstll or kicks with hard-over rudder, even the worst
handling ~>hips will re9p.ndling tools, especially when
moving larger ships where speed is critical and tolerance for error small.
GPS units, especially those with a differential or wide area augmenta
tion system (WAAS) correction, provide an extremely accurate indication
of speed over the bottom. Bear in mind that the speed shown is the resul
tant speed at which the GPS unit's antenna is moving. Even when a unit is
interfaced with the vessel's gyro, the speed provided by the GPS becomes
less useful once the vessel begins to swing.
Fixes by r adar or visual bearings are neilhe1· convenient nor suffi
ciently accurate for determining speed in a dockiug situation.
The position ofthe ship's quickwater, that is, the wash from her propel
ler as the engine goes astern, is extremely useful to the ship handler at low
speeds. If that quickwater falls behind the ship when the engine is put
astern, the vessel's speed is 3 knots or more. When the quickwater begins
to move with the ship, the speed is about 2 knots. When the wash reaches
the midsection ~he ship is de::.d in the water. Since 2 knots i!' ,1 comfortable
..lpr;.ro&ch apeed for an average sizP. ship, it"s convenient to be able to put a
iight on the water at mght and tnen go c1slcrn untJI you sec by the position
of the ship's quickwater that the speed has been reduced to the desired
!?-knot speed (fig. 4-2).
Some experience is needed before the relative mot10n of passing objects
can be used to estimate ship's speed, although it is possible for an experi
enced seaman to judge speed visually with surprising accurncy. How does
120 APPHOACHING THE BERTH
~--
a.
:c
Cl)
cti a.
:c
Ill
~
"'
Fig. 4-2. Estimating headway when backing. Note: 1'his figure depicts
the quickwater from a right-hand propeller. The location of quickwater
at various speeds is reversed for a left-hand turning propeller.
an experienced seaman becoml) experienced? By practice! Estimate y')t.r
ship's speed of approach at !)Very opportunity and compare it. with the
speed shown 0n a Doppler log, or the speed indicated by the time required
to advance along a piE'r of known length, or by comparing your ~stimate
·with that of a more experienced shiphandler such as the docking ma:ter.
Apprehension is usually the result of uncertainty, and the ability to judge
your ship's speed with reasonable accuracy will do muu use them t>s a reference
you'll find your ship is going too fast wh.:!n she reaches the berth. Try an
experime'1t to sati~;fy yoursc!fth!.\t this is so. 3land in the wheelhc.use at
night when the ship's speed is most difficult to ju::!ge and, while watchmg
an oi.Jject ashore located forward of the beam, :.low your ship to a minimal
speed. Now look abaft the beam n.1d see how fast you are actually moving.
Judging absolut.e speed visually can be difficult, but it is possible to de
velop some rules ofth~b to improve your accuracy. For example, at the
Panama Canal the pilots usthe opposit.e situation and requires a greater degree of skill.
All of the aforementioned means of judging speed give t;hip's speed over
the bottom except the use of her quickwnter.
REDUCING SPEED EARLY
Speed is especially impon.ant during the approach since a ship is less con
tJ·ollable when her engine is used ast.ern to reduce headway. If speed is
kept to a minimum it is possible to use the engine ns needed without arriv
ing at the berth with excessive headway. If speed is not reduced early in
the approach, the shiphandler finos hin.selfwith a tiger by the tail-nce:d
ing to reduce speed and yet having to u~e the sinp's e!1gines nl-.ead !.o con·
trol the ,·essel when shaping up for docking.
Many shiphandlers make it a practice to stop a ship completely about
cne ship length from the berth, especially ut n ight when it is more difficul t
to estimate a vessel's speed. TI1ey are then certain of the speed-it is
zero--and can use the engine as required without concern about arriving
at the berth at an excessive speed.
122 APPROACHING TilE BERTH
THE APPROACH
A good docking actually begins lo:1g before the ship comes £a longside the
oier. The ~pproach is at least one third of the rl0cking. Tfthe speed is re
duct;!d, the sh1p pro!Jerly lined up with the piP.r or wharf, and then steadied
up so that all lateral motion is elir:~inated , she practically docks herself.
When berthing starboard sidOl
\
I
I c c
0 ~)
~I
\
I
tern on a hawser when berthing the ship stern in. This ht?s
many advantages. The ship's engine can be used with ahead revolutior.s
together with the rudder to steer the ship, while the tug continues to keep
her moving astern by pulling in opposition to the ship's ~ngine. Ce>nsider
using a tug on a hawser in this situation. ·
0
STERN-IN API'HOACII TO,\ PICH
0
0
PoSIIton ptvot point
so stem sv..ngs :!ear
ano snop lines up
with sti~.
Tug may be used on
hawser astern Ins toad
or on shtp's quarter.
I I
Fig. 4-5. Docking stern in at a slip.
!f!lo ----:;-
0
0
Always avoid pushing with the tugs so long that excessive lateral mo
tion is developed towards the oerth, causing the ship to land heavily
against the stringpiece. It is the lateral motion that the less experienced
shiphandler has the most difficulty detecting and controlling, and a mari
ner will never become a shiphandlcr without being able to appreciate
sideward motion.
The importance ofhaving the stern tJg stand ofT until actually needed
was discussed in the previous chapter. This is especially important when
planning a stem in docking. The stern lug must not make fas t u r. til th.:
ship has turned to bring her stern toward the slip and is dead in the water.
Until then, the tug aft is of little help and may fall J.ro;;r,d ll.!idC'r tht co~r>
ter and have an effect opposite lo that desired. Preferably, t.he aft tug doc.s
not come alongside t:ntil the .3hip is entering the slip, since once fast, tit e
after tug-by her w~ight and underwater profile alone-sets the stern to
ward the pier as the ship comes astern. This eiiecL is amplified when dock
ing porL side to since the stern tends to move to port anyway when the
engine is going astern.
126 APPROACHING Tl!F. 13ERTH
The bow tug is best made up withonly a backing line so she sin1pl:' fol
lows the anip into the 3lip, trailing on the line in a position uow tc bow with
the ship. She comes ahead on either bow to s t.ePr the ship into the slip as
r equired, without havinJ the effect of se tting the s hip towardA the bter's observations and was proud of his ship and crew.
"It's true Pilot. They do work well-probably because most of them are
pemuznent aboard and know what is expected of them," replied the captain.
"Th~y r:;tate cts a team-mates and engineers, and most of the unli
censed crew-so they /mow the ship and each other. Makes for a safer and
more e{fic:ient operation, that's for sure."
"How .::ome more ship.as hindrances to be overcome, rather than as
aids to be u.;;ed with the rudder, engine, tugs, and anchor to put lhe sh1p
alongside a berth in a safe and scamanlike manner. A powerfult,ug can
combat a moderate wind and cw-rent, although at be:;t the docking will be
sloppy, but even the finest tugs do not make it possible to fight a 1'troug
wind or current. Nor is it necessary for them to be asked ln.
Before starting th,:! docking, get out on the bridge wing and feel tht..!
wind anJ weather on ·your hce. Look up at the stack and dow:~ at thew::.
ter. Look out to the horizon and \:heck wha.: the future weallwr condi ticn:;
might be. Constant awareness of wind, weather, and current is cssenti:1l
to efTective shiphand ling.
How do the effects of wind and current compare? Air is about nin e hun
dred times less de than water, so for a gir..•en velocity wind has mu.:l1
less e1Tccton the ship than current. An increase in the velocity of either the
\
130 DOCKING
wind or curren t will increase its efTect on the ship, both varying as the
square of the velocity. The relationship ofdeGsity and velocity to prcr,sure
is expresis eny other profes
sional, to make allowances for wind and current. It is eq_ually important
that the shiphandler also develop an appreciation for the less obvious lat
eral motion that results from:
1. Turning a.3 the ship is approaching the berth.
SF;TIING Ul' TO IlACI\ 133
2. Extended use of tugs.
3. C'1ecking or holding the li:1es before the shit> is alongside.
These actions cause sidcward motion independent of any mNion
caused by the wind &nd current, even when the ship is :naking no head
way. If not checked, .the ship move:s laterally toward or away from th11
berth or comes alongside with excessi,·c force. Lateral motion may be de
sirable at times and is not so much an eiTect to be avoided as a factor to he
watched for and used to advantage.
Lateral motion is easier to detect wl.cn working from trc centerline of
the ship because you have a better view of the vessel and her heading.
Watch objects ashore located ahP.~d or astern. Use their change in ali gn
ment as a range to detect latera1 motion, and note when the distance from
the pier increases or decreases independent of heading, wind, and current.
The abi lity to detect this sideward slide through the water and make
use of it is a mark of an accomplished shiphandlcr because it is one of the
effects that is least appreciated by an inexperienced pilot or master.
SETTING UP TO DACK
Prior to going astern, especially when docking without a tug aft, a sin
gle-screw ship should be set up so her inherent twisting ciTecls are an aid
rather than a hindrance. Since the approach is plmmcd to allow for this ef
fect, only one additional mancuver is required.
Whengoing starboard side to the berth, put the rudder to port and kick
the engine ahead until the stern develops a slight swing to starboard. Note
that it is necessary to consider the rudder's effect on each end of the ship
¥ather than simply on the ship as a whole. Near the berth the rudder is of
ten used tu move the stern rather than to change the ship's heading. After
this slight swing of the stern to starboard has bebrun, go astern to 3low or
stop the ship. While backing, the :;;tern checks up and probably moves to
port as the propeller and quickwatcr take over, but any movemen t of the
stern to port is minimized since you shaped up to back prior t.o pulling the
engine aslern. Thu maneuvcr is repeated as requ1rcd !>ll the ship is
s!.oppeJ in position and pc.rallel to the pier or wharf (fig. 5-2).
When berthing port side to, the ship i1:1 set U!J to allow for t.hc sarne
swing of the stern to port. Since the ship's angle of approach decreases
each time the engin11 goes astern, the initial angle of approach is greater
for a port side to docking. The rudder and engine arc used to check the mo
tion tt. port as r.ccessary so the ship does not come parullcl t.o the berth
I
\
134 DOCKING
1. ·'Kick' the engine ahead, rudder hard left,
swmging the stem toward tho dock and
countering the twisting ertect as (see no. 2)
2. The engine is po.11 astern. The swing is
chec~ed !Jy the ,...,jpeller's to•qu;, 12nu
the quickwc.ter as the ship stops
\ ~ _ parallel to the dock.
:=.'\== r;r--u ---- e···">
.......,;._)~"!:) .... ~--~--- - ------- - -
Fig 5-2. Docking st.arbonrd s ide to-set.ting up to back.
untii she is in position. The quickwater partially checks the sw:ng so the
ship la P.ds easily.
Knowing that the ship swings in this manner, it is logical to use astern
bells to change her heading to starboard rather than only the rudder. This
provides an opportunity t.o simultaneously slow the ship and change her
heading (fig. 5-3).
Don't overuse the rudder when docking. The rudder can oflen remain
hard left during t.he final stages of a docking maneuver whether docking
port. or starboard s ide to, s ince it has so little effect at these slow speeds. The
hard-over rudder is in the position in which it will most likely be needed,
and having it in this position saves time required for the steering engine to
move the rudder should it be needed to check the ship's swing. Do the same
when backing the engine in an anchorage or during other maneuvers when
the ship has little or no headway-the rudder need not be shifted when
backing the engine unlt!ss the ship develops significant stemway.
QUICKWATER
Quickwater develops when the flow from the engine going astern starts
moving up the ship's side. This occurs first on the starboard side at about 2
knots and by the time the ship has little headway there will be consider
able flow u.p both sides of the :::hip. The quickwater strikes first on the
quarter so the stern moves away and the bow heads toward the berth, and
its effect is more pronou'1ced when docking starboard side to. The quick
water eventually moves up the full length of the: ship so she is affected
equally fo :-t> and aft, the cushion being used by t.he ship},andler to reduce
the ship's lateral motion or move the ship away from the dock.
Like other forces that a ffect a ship, quickwater is planned fur and used
as an a id by the compete nt. shiphandler . Quickwater affects a docking or
IHUDGE M1\HKEH$
\~;. ··h
~ \':\
:\0,\
\\ \i
j_.,\ \ -~.
U~c the lwisling cllcct
when backing to
simultaneously tum
and stop the sh•p .
----....,.,,R' ~·,.\y :.
L~·J}
Fig. 5-3. Coming alongside-port side to t.he dock.
135
undocking ship but is strongest when there is shoaling or a bulkhead un
der the berth. This contains the flow and increases the presst..re acting
upon the hull. If the ship approach~s with excessive speed, it is necessary
to back more strongly than desired for a grea ter length oftime, and result
ing excessive flow of quickwnter becomes a problem in spite of the best
planning. This is one more reason for approaching at the minimu m possi
ble speed.
BRIDGE MARKERS
Common sense dictates that a marker or light be placed on the stringpiece
to show the location of the bridge when the ship is in position. Unfortu
nately, this is rarely done. Too often the ship is alongside with the first lines
run before someone on the dock decides that she should shift 50 feet ahead
or 30 feet astern. Aside from being botr. annoying and unprofessional. this
?ractice cost" both -h':! sh1p and the terminal a great dca! of lim~ and
money. The stevedore or terminal operator knows where the working h!itch
or manilold should be spot ted, and every shipmaster knows the distance
from the bridge to t.he bow or manifold, so the bridge location can easily be
marked on the dock prior to bringing the ship :llongside.
Shipmast.ers and pilots must. work to make the use ofbridt;c markers
and lights more common.
.I
I
~
136 DOCKING
USE FINESSE, NOT FORCE
Keep in mind when going alongside that you are bringing a moving object.
of r.onsider:1ble 'llass alc•t'gside ar. llnforgiving and immovable p1e1 or
wharf, an evolution that requires some degree of finesse. Beware tlw
shi}'mat:~tcr or pilot who tells in most graphic tcrn1s how the ship wus
"forced" into a berth against wind and current, having beeu ''belied" full
aheaci and full nstern until she was "driven" alongside the berth within
feet of certain calamity. This is no professional speaking!
Shiphandling, like lovemaking, is a subtle art: the ship is not driven by
the shiphandl~::r, she is caressed, and this must be foremost in your mind
as you give those last commands to ense the ship alongside.
GOING ALONGSIDE
It is extremely ioportant that the ship is flat to the stringpiece as she co
mes alongside. This i3 true for several reasons:
1. The frames through the entire midbody of the ship can absorb the
impart of landing, rather than having the impact ccncentrat.ed
wi~hin a small area of the hull.
00
00
Fig. 5-4. " ... and just think, First, that pilot dockeJ with 'finesse.'"
Al.L ';ECUHE
2. A p;.rallellanding traps th(' maximum quantity t-f water bt>twccn
the hull and the pier or wharf, and thus develops th,• m:1ximum
cnhioning effect.
3. The eddy currc.mt. ar.t11 equally n!,JIIg the cnlin: lf.mglh of the ~ hi 1J,
l.llowing hc1· Jutcralmot.ion and UHI.ling the lnnding.
4. If Lhe ship is docking with any current, having the ship's upstrea m
end hard alongside keeps the current from ge ... ting msalc the ship
and forcing her back off the berth.
5. The maximum cushioning effect is gained from the sh1p's quick
water when the ship is parallel to t.he berth.
When the impact oflanding is spread over the entire lcnglh of lhe nnt
parallel midbody, and several hundred feet of nearly incompressible wa
ter cushions that landing, the ship can go alongside with surprising force
without damage. The reverse is true when the ship lands at. any angle to
t.he berth. It is common to see water trapped between the hull ami a
solid-faced pier or wharf go several feet into the air as the ship coml!s
alongside, indicative of the energy that this hydraulic cushion is absorb
ing. If the hull has any angle, the water rushes toward the end that. is fa r
thest off the pier and the cushion is lost.
ALL SECURE
The ship is alongside and the lines are being run ashore one afl.er tlw other
to make her fast. The number and placement of these lines vades with the
location and construction of the pier, the type and size of the si">ip, and the
weather a nd current condi tions that are expected.
Ships usually run sufficier.t. head, spring, and stern lines that. kee p
the ship from moving forward and aft. Unfortunately, tncse lines arc of
ten a :1indrance rat.her than an aid in keeping the ship alongside in a
strong current-especially after t.he ship has beenallowed lu gel off the
pier at one end. The tidal current t;ets on the inshore side of t.he hull ::.t
the bow or quarter, an eddy current develops to further increas(' the
strain 011 the lines, and the ship moves ahead or usLCrn into the curn nt.
The ship rides outward a nd ahead on the lines, pivoting on tilCm much
like a wr tHskier at. t.he er.d of a towline, while the lines at the oppostle
end of the ship pull her in so she begins surging up and down the p1 cr.
This surging occurs because there is a greater strain on th:! upstn~.-:. m
lin es than on those lead in!: downl.ltrcu m, nnu cnuses shock lv~uling that
parts lines.
'I
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.J
138 DOCKING
Breast lines, the lines that a rc most ~ffect.ive in keeping the ship along
side, are too often overlooked although they should be doubled up like any
others. If there are sufficient breast lines to keep the shin along:-:id", the
strain on t:1e lines leading forward and aft remains equal and the ship
does not begin su"'ging.
The surginr, is aggravated by passing ~:~hips whose hydrodynamic
forces move the bertherl vessel first away from and then i..oward the mov
ing vessel, while also pulling the docked ship off the wharf. A pressure
wave moves ahead ofthe approaching ship, and there is a decrease in pres
sure between the two ships due to the flow·ofwater as they pass. It is espe
cially important that the ship be kept hard alongside, wit:1 sufficient
breast lines run and ulllines up tight, at berths exposed tJ passing ship
traffic.
Remember too, Mate, to call the ship that is approaching at. excessive
speed on the VHF radio and tell her to slow down. No longer is it necessary
to stand by and watch a catastrophe develop because you cannot commu
nicate. Look over the side and make sure the ship is alongside, then go to
the VHF radio and tell the passing ship to pass at minimum speed with the
engine stopped to ensure that your vessel is not pulled off t he pier.
CHAPTER SIX
UNDOCKING
Many are the boys, in every sea pm t, who arc drawn
away, as by nu almost irresistible attraction, from their
work and Sl.hools, and hang about the docks and yards
of vessels with a fondness which, it is plain, will ha"e its
way. No sooner, however, has the young sailor hcb'Uil his
new life in earnest, thun nil thb line dro cry falls ofr,
and he learns that it is work afl.cr all.
-Richard Henry Dana, Two Years Before the M0$1
Cargo operations complete, the ship lies quiet for the first lime in many
hours. The shore staff are gone, leaving you with a desk heaped full of
memos, magazines, and unopened mail. The short stay in purt was hectic
but you enjoyed it both because it marked the en4 of one uoyage and the be
ginning of another. Perhaps it is just because your work has these bcgi n
nings and endings, rather than going on interminably as jobs ashore seem
to do, that you.stay at sea.
The telephone interrupts your reuerie.
"The pilot is on the bridge, Captain."
Another voyage has begurl.
PLANNING THE UNDOCKJNG
Take the same care when briefing the undocking piloL as was taken with
the pilot who docked the ship; exchange •,he same information and data
card. 13e sure to inform the pilot of the status of the anchor in addition to
all the other items outlined in previous chapters, especially if they are
backed out of the hawsepipe or if one wus left on the bottom after docking.
It is surprisi.::~g !1cw cftP.n the doc!dng pi!o~ flnds out that there are two
shots of chain in the water after letting go the last line.
As you did before docking, get out on the wing and feel the wind, check
its direction by looking up at the stack gases, 9.lld look over the side to cheek
the current. No matter how many instruments you might have to supply
such information, it's still important that you u.c;e your own senses and get a
feel for c>xisting conditions before planning this or any other maneuver.
139
I I '
. ··-1
I
140 UN DOCKING
Too often, the less experienced shiphandler looks upon undocking as a
relatively stmpl~ opc.raticm and does not properly plan the evolution.
The ship is usualh undocking stern first from a berth, so she steers
poorly if at all. Since she is starting from alongside, the shiphandler I, as
fewer options available that make use ofthP. wind and current as the ship
begtns ba eking from the berth. During a docking, wind and current are fc>lt
when the stern is in clear water and the angle of approach can be adjusted
to make use of these forces. This is not the case when undocking.
Even the rr.ost careful planf may have to be altered after the linea are
let go since it is difficult to determine which of several conflicting forces
will most ~ffect the ship leaving the berth. Often the shiphandler lets go
expecting to be set ofl the pier by wind, only to remain hard along3ide due
tO subsurfr.ce current. If this occurs, take time to replnn the undocking be·
fore touching the telegraph. The ship isn't going anywhere-more acci
dents occur because of inappropriate action than delayed acticn.
DRAFI' AND TRIM IN BALLAST
The directional stability and handling characteristics of a loaded s:1ip
were discussed in previous chapters, so it is assumed that the ship is now
in ballast and light. Ideally, she is ballasled to at least a moderate draft to
submerge ';he propeller, rudder, and bow thruster, and to reduce windage.
Give he~ a few feet of drag. The amount of trim by the stem depends on the
handling characteristics of the ship, but it is better to have a bit too much
drag tha~ not enough. Try to at least get the stem well down if stress or
loading conditions limit ballasting since:
1. The ship has excellent directional stability with good drag.
2. The propc.ller and rudder are then most effective. With a deeper
draft aft the ship steers better, requires less distance to stop, tv:ists
le:Js when the engine is put astern, and requires less rudder to coun
ter the torque of the propeller when going astern.
3. It is. preferable that the bow also be ballasted to at least a moderate
draft to reduce windage and submerge the bow thruster so it is ef
fective .
If a choicP. must be made, however, between getting the bow down or a
proper draft aft, choose the latter. It can be a challenge to hold a light bow
into the wind until headway develops, but it can be done usiug a tug or the '
USING QUJCIthe ship alongside
and reduce the strain on remaining lines while singling up.
Short lines hold the ship alongside more effeclivc!y and still keep her
from moving forward or aft, and they can also be brought aboard quickly-
especially important aft since the propeller should be cleared as soon as
possible so the engine can be used.
As ships get larger, winches are geared down to handle the higher
loads and thus are slower. It is therefore important that the crew be: in
formed if the iast lines must come aboard particularly fast. The mate can
leave the shortest line ~ntillast, ar.d lead it to the winch bcfc-rt: }e ~t!n~ ;;o
to get the propeller clear quickly.
USING QL'1CKWATEH WHI::N UNDOCIGNG
The shtp's quick water can be an effective tool during the undocking, c:.pt!
cia lly when backing from a wharf or pier, since the ship is passing through
the quickwat.er as she moves astern.
142 UN DUCKING
Leaving a starboard side berth the quickwater forces the stern away
from the dock or wharf, the•1 moves the ship laterally and, when there is a
good flow striking the hull forward of the pivot point, ch~:cks up the swing
0 1 tne bow toward the pier. The more restricted the flow of quic.Kwater
along the inboard side of the ship, whether due to shoaling under the berth
or to the pier or wharfhavin~ a :>olid face, the more effectithas on the ship.
Quick water ha:; less effect when leaving from a port side berth since it.
is inherently leFs strong on the port side of the ship and is .\cting in more
open water due to the ship's angle to the pier as she starts to bark.
Quickwater has a minimal effect. ".lut does reduce that angle to the berth as
it strikes the forepart of the hull.
With somo planning, the quickwater can be used to neatly move a ship
with the min.mum of bells and rudder orders. For example, a ship can be
started astern until the stern begins to lift off the pier. The engine is then
stopped and the ship drifts astern while the quickwater moves forward
to strike the hull ahead of the pivot point. The swing of the bow toward
the pier is checked and the ship backs straight astern, clearing the berth
in a neat a:ad seamanlike manner. Quickwater is discussed further in
chapter 5.
UNDOCKING FROM A WHARF
Take advantage of any current from ahead when undocking from a wharf.
Delibetately get that current inside the ship and create the situation you
have been avoiding while the ship was berthed. The current moves the
bow off the wharf as you use the engine and rudder to lift the stern without
developmg any head or sternway over the ground (fig. 6-1). The ship
moves lRterally off the berth.
A certain feel is needed when adjusting engine revolutions so the ship
makes no headway but sets away from the berth in the current. Use suffi
cient engine revolutions to keep the ship abeam of a selected point on the
wharf while walking her laterally away from the berth. When wind and
space limitations make tug assistance necessary, the tug is backed as re
quired to maintain the ship's angle to the whP.rfwhile the current takes het
off the berth.
Greater lateral force and control are needed when ships are berthed
close ahead and ustern, or a wind blowing on the wharf overcomes the cur
rent. Eithl!r use a second tug or back the bow tug while the ship's engine
turns aheaci with more power and hard-over rudder (fig. 6-2). In the latter
case, the tug and engine work against each other to prevent headreaching
~c:
Ul\OOCKll'G FHOM A W!IA!n'
1. Current hits bow (and ship t:.od'ly)
Jway from tho wharf. R.Jddor and
engono move me stem.
8
Current ----:·-----
\\ -----~----------------- ,.,,-: __
,-- I ..... ..... .Af"
........ \l, '
::::::/~ v e '> . ~ -- ---------- ------------
2. RPMs adjusted so the st.ip makes no heact ... ay
over tho bottom Yihllo moving laterally.
Fig. 6-1. Undocking-current from ahead
..
while moving the ship off the dock laterally. The ship maintains an nog le
to the wharf so the current can assist the lug and engine in moving the
ship off the dock. A more detailed d;scussion of this technique is found
later in this chapter.
When the current is from astern, the ship is undocked in much the
same manner as she was docked under the same conditions. Work the bow
toward the wharf using the tug, engine, and mooring lines, and then back
into the stream. If a vessel is berthed astern, use the engines as necessary
to match the current as the ship works laterally ofT the wharf. Again,
maintain a speed through the water that matches the drift of the current
so the ship moves laterally over the ground.
A ste'lm-turbine-powered ship can easily maintain the required speed.
Communicate with the engine room by t.ele_r,hone rather than telegraph tO
ob tab specific revolutions instead of using standard maneuvering speed3.
A motor ship requires more attention since a high-speec.i diesel has a
dead slow that often exceeds the required speed. The engine must be
stopped intermittently to make good the needt:d speed, a maneuver that
requires .1ome praclice. A variable-pitch-propPlle:d motor s:1ip has ar. ad
vantage in this situation since the pitch can be ,reduced to exactly match
t he drift of the current. '
144 UN DOCKING
1ug's power opposs:- the ship's ongine.
Ship mov11s away from the benh but makes
no headw3y I
==============~+================ ----=------ ,~~···,·:,," c
B Jl ,,• ,,
(AB+ A'B' = 0]
Current
A'
F ig. 6-2. Moving the ship luterally off a berth (one lug).
To take a ship off a clear wharf at slack water, put her bow nt a small
angle to the berth and steam ahead. Use the rudder with car~, lifting the
stem while maintaining the ship's angle to the wharf. If the wharf is not
clear ahead, the ship is either worked off using the engine in opposition to
a tug, or the bow is pushed in toward the pier and the ship backs off as de
scribed later for a port side undocking from a pier.
BACKING FROM A SLiP
This commagainst s~aip's lines.
The torque of a propeller going as tern walks the stern to port so the
ship comes back parallel to the berth as ~tern way ncvelops. She then co
mes easily out of the berth and is turned as required once th~ pivot point
clears the pier (fig. o-4).
Whether backing from a l'Or t or starboard side benh, the bow tug ei
ther backs along with the ship, using a stern line as required, or falls
I
\
I
146
' ' '
'
' . . ' , .
! ~ 3 !
' "
' I
'
UNDOCIf the pier and the ship is turned fair in the channel. This is the
!lACKING F'HOM A SI !I' 147
safest mnneuvcr when there 1s no tug assbta1 cc Sl!l~'t' the sh:p i:;
alongside at ull times until clear and thus cannot be blown ugain.::>t
lhc pier and dnmnged. ~he may ln:-H' H'lllC pui;,t w!1ilc slid in:; alone
but this is inconsequential since Mp.1int ::omes in buckets whde :slei!l
cnmes in shipyards."
2. Putting the ship at a good angle to tlH' berth by working against the
spring line and then backingclear.llowcver, the entire ship body, or
more likely the ship's bow, may be blown back down on the pier and
damaged when undocking in this manner.
3. Breasting the ship ofT with one or two tugs.
The ship's behavior once shuvcr when the ship is stern in and has to turn awny
from the pier with limited maneuvering ruom is to wait for a tug. There are
maneuv~rs that can be used but they depend on so many things going well
that the risk of accident is excessive .
CO:O.IlNG OFF PARALLEL 1'0 A tEHTI! H 9
Fig. 6-6. Uodocking bow out from a slip .
COMING OFF PARAIJ~EL TO A BERTH
Often a ship must come ofT a berth while remaining parallel to the
stringpiece, such as when she is berthed in a oan ow slip, or docked star
board side to with a ship as tern, or bcrliled at a wharf with ships close
ahead and astern. There are several wuys to accomplish this:
1. Use a second tug made fc.st aft to lift. and control the stern dming the
undockiog.
2. Lash up the bov.: tug facing aft and use that tug against the ship's en
gines as discussed in chapter 3.
3. Make the bow tug fast in the usual manner and back that tug to lift
the bow while the ship's engine is coming E head with the rudder
hard over toward the dock to lift the stern. Sufficient engine revolu
tions must be used to coun t.E:r t he tug's power as they work against
each other, so tilC ship maintains her position over the bottom, th at
is, relative io the berth, but moves laterally away from the stri ng
p;ece. (See figure 6-2.)
Thesw~rd a shoal or anot!:~r ship ifthas nnothtr-tlw us ~.: of ship :•nd t t',;s .•l to
mean a vessel of nny kind or si.~e. A love 11f work on t!1c ~·utcr i.;: n~t re·
.;tt·idl ai{Jne.
Ol,ay, .\fntc.. nuti{y the cngin, ru'JII! thntthetm·ad. '! 1· , S,• ,·ret s all!'ad T:..
:-;hip is starti ng to fllhe shelving bottwn, n ormnl to a :.:;
pnrl cnll.
Till' master has reviewl.'d the appropriaLesuahngcliredions, hgh t hs t.- .
local nolit-e:s, and rhnrls of the area, and has prepared a wurst• card 1-'hP\\
lllf: Nur~es and the th!'tanrPh lwtwcenlhc significant navtgalwnnl auJ , ..,
,Jiace alon~ the channel to the dock. Soon the gear will be tcslr of d Ppth Jps,; than l.!i llt:ws the vc sscl 's cl r.t fL (fi l:· 1-1 ~u l !n~
7
8
I
48'
Depth = 1.2 x draft
F•JII shallow water
oflact :ell.
t
6'
i
ARRI VAL
Depth = 1.5 x dmfl
S hallow water effect
40• becomes signlllcant.
60'
Z 20'
~
Fig. 1-1. Depth vt:!rsus shallow water effect.
marked chanr,es in ship behavior that occur in shallow water will be ap
parent. The se!"ies of mnneuvers should include
1. Hard right turn nt 6 knotr. .
2. Hard left turn at 6 knots .
3. Daeking a n d "illing maneuver starting from dead in the water.
4. Half a~ tern to bri.1g the vessel dead in the water from 6 k nots, 1eav
ing the rudder amidships.
5. A serier of hacking maneuvers , until the vessel is dead in the wai..er,
using '.he rud~cr a nd engi ne as required t o keep the ship's hi!ad
within 10 degrees of her i.1it ial course.
6. Backing fo : ten m mt.tes. !'tar.:ing with the vessel dead in the water,
ke9pmg the t·uddt>r· amidsnins.
7. Turning with the bow thruster, i f fitted , to th e right and left across
t he wind . This should be done at 3 knots and at 1 knot.
If your ve!'lr.e l is nonconventwna l (thnt is, equipped ~ith twin screws or
nu Azipod-type l'lYALem ). you should perform ench of these ma ueuvers
HAHD Hlr.IIT Tl'H:-1 1\T u 1\SOT:-i !I
again in such a manner us t.o simulate the loss of om• engine, a steeri ng
failure, or other cnsualty. Learn !tow your vessel responds to va rious com
binations of rudder posiLion andior enguw use. For •xe.mple , t :·y tu rn i n:~ n
twi n-screw v•!ssel to starboard with the port engi t.e butweet! the turns LO the r!ght anu t,urn:; to thl'
lefl for these largest of vessels ,lri.! insignificant.
However, there arc disadvantagts to tt•rning to tl.e lcfl when manuu
vering in con!ined wuters that fa r outweigh this one ad\anLagc of slightly
reduced turning diameter . Thusc other consideratiOns, such as lhc ability
lo back and fill , a re discussed in following sections.
BACKJ?\'G AND FILLING
For the purpose of these trials, this -:ommon mnncnvcr is started with tht'
vessel dead in the water. The engine is brought to half ahead and th~ rud
der is putfurther than planned be
fore getting an anchor down and the ship stopped.
Make it a rule-when handling a ship, back toward open water.
I,E:FT-HAND AND VARIABLE-PITCH PROPELLERS
Keep in mind that the maneuvers dt:!scribed herein are for a ship fitted
with a right-hand or clockwise turning propeller. The rare ship having a
left-hand turning fixed propeller is handled in a manner opposite to that
described, that is, a starboard side undocking (or docking) of a ship fitted
Fig. 6-7. "Rule number une, gentlemen. Always back awa:v from danger."
TURNING TO SEA 101
.vith a left-hand turning propeller is done in the manner previou;,ly Je
scribed for a port-sirle undocking (or docking).
Variab!e-pitch :>hips often have right-hand turning propciicrs. Th~se
propellers turn in the same direction whether the ship is goir.g ah::td or
astern nnd only the pitch is rcvenied to back down. The propeller is there
fore turning clockwise when going astern, just like a conventional fixed
pitch left-hand propeller, so such ships are har.dlcd hke vessels with
left-hand turning propellers when docking and w1dock.ing. Variable-pitch
propelled ships should be 3tandard.ized, all being fitted with left-hand
turning propellers so they back iike other ships that. the shiphandler is ac
customed to handling. There is no standard at present, so the shiphandler
must check the direction of rotation of every variable-pi \.eh-fitted ship be
fore planning the docking or undocking.
TURNING TO SEA
Turning in relatively open water is a st.raig~tforward joL as long as the
shiphandler minimizes the ship's speed. Thter may quit or refust• to
stop when used, o~ a problem may arise th.1t requires more effective power
than the bow thruslcr can develop as lhe ship's spcNl increases.
When dismissing the tug, lower her lines with a messenger. Dcn't d•·1Jp
them from the ship's deck since a line in the water may toul the tug's screw
or your own. Dropping the linealso makes unnecessary work for th e tug-'s
crew since the line could have been lowered on deck rather than ha vi I ll{ t.o
be dragged wet from the water. Listen for the tug's signal, often a long
blast on her whistle followed by two short blasts, so she cun be let go
promptly as the ship starts to come ahead. Keep at least two crew mem
bers and a mate standing by a t.ug at all times, ven if she is to be held for
some period after clearing the berth.
The ship now turned and headed fair, lhe docking mast r wishes a ll a
good voyage and climbs down the ladder to the waiting tug belo···.
\
i
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CHAPTER SEVEN
DEPARTURE
Captain N. D. Pa!mer was a rough old sailor. He ·vas de
tennined to sec me gel along, and helped JT1e more than
any other man to know my duly as an officer and tJ f.t
me for a 1\~aGter.
- r.nplain Charles Porter Low, Recollections
Downbound and light, she mad£ good time despite the flood tide. The uld
man, tired {1·om the short, hectic stay in port, left his chair only to glance oc
casionally at the chart on the wheelhouse log desk. He had little inclination
to make conversation with the pilot, now ten minutes into a monologue to
which only the third mate was really listening.
Fresh ~offee in hand, the mate returned to the log desk. She noted the
time on the chart as the ship swung onto the next'1ange, comparing the
course that the ptlot had given to the helmsman with the previously inked
and labeled courses on the chart.
"Right to one, five, four."
Checking the swing, the A.B. on the wheel repeated the new course,
"One, five, four, Sir."
"Very well, steady so."
"Trouble is, Mate, they always have to be looking for problems, and if
there ann't any they create some. It's part of life today but it sure is hurting
the marine industry."
The mate had heard all this before, and always some mysterious "they"
were causing the problems.
"Who are 'thev 'Pzlot?" she queried.
"Industry gro-~ps, government agencies, the Coast Guard-l'':!cJOII•C communzt~ •• at
both the national and international lel'cls, was long OPerclue. The captuu:
appreciated and shar..:d thl'se coltcents.
"There is n lot of expertise c.m the water todtJj', Mate, an cl the stand c. rds
in the industry suffer whw actiue professionals a re exclucleJ.ji·vm discus
sions of matters affecting the marine industl)'·"
Picking up the phone to instruct the standby to rig the pilot ladder, the
third mute nodded her agreement.
"You're right, Pilot, we're letting the tail wag the dog in our industry. n
"It's a good way of life, Mate, and we can't let others use politics to down
grade it. We haue to become more involved in matters affecting our profes·
sion ... (Note: This was written in 1983. The situation has not improL..;d.)
DHOPPING THE PILOT
Well before arriving at the pilot station, the master and the mate on watch
discuss inbound and outbound traffic with the pilot. All slups arc identi
fied by name and their intentions clarified 30 there is a smooth transit ion
oft.he conn from pilot to master. It's easy for the pilot to discuss any pot"n·
tial problem situations with the other ships before he leaves s ince he has
radio contact with both the other pilots and the pilot station. They know
the destinations, drafts, nationalities, and intentions of the :;hips moving
in the area, and are able to assist the master in making safe meeting a r
rangements before the pilot disembarks.
Until t.he master is fully coniide.1t that there will be no problems as the
ship departs from the port area, he should not release the pilot. Being a re·
sponsible professional, the pilot has no objection to perfonning this last.
service before leaving and the master must not. hesitate t.o require it.
DEPARTFRE SPEED
A lee is made and •hr· pilot boa rds his boat tn go ashore. The sh1p returns to
her heading and proceeds to the departure poinL at a speed that matches
the flow of outbound traffic. Moving at tl.at speed obviously reduces by
half the amount of traffic that must. be deall wit.h since now only crossing
and meeting ships present any potential problem::;. Time saved does not.
justify excessive speed, and any fool can engage in false heroics wi th a shi p
that belongs to someone else.
I
I
r
158 DEPARTURE
Fig. 7-1. "Cap', could you slow her down a bit while I board the pilot
boat?"
Speed i& also limited by depth of water. Trying to push a ship at a speed
faster than proper for the depth of water causes excessive squat and suc
tion and, since the flow of water to the rudder is restricted by the
underkeel clearance, the ship becomes hard to steer. Increased difficulty
in steering and the pronounced vibration that can be felt throughout the
ship are certain indications of excessive speed.
This remains true until the ship leaves shallow water conditions, not
just while the ship is in a harbor or channel. AB the ship reaches deeper
water, her speed should be increased incrementally, rather than being
brought to sea speed upon departure. This is increasingly important as
ships get larger, not only hecause of the inherently greater drafts of
VLCCs, but because of the higher horsepower and tendency of the larger
hull to develop harmonic vibrations under shallow water conditions. As
5,hip size increases, the master must adjust shiphandling habits.
Make every effort to move with the flow of traffic whether there is a for
r:~al ~raffi~: s.:parat;on scheme or not. If a problem develops, do not hesitate
to slop the ship and let the situation clear itself up. Since the master and
mates have developed their shiphandling skills, maneuvcring while
maintaining heading and position should present no problem. Too often,
lhe less experienced shiphandler tof local waters
and is able to navigate mainly by eye, so full attention can be given to traf
fic and sbiphandling. The shipmaster visits many port.s and cannot possi
bly develop the pilot's working knowledge of any particular pori; another
person is therefore needed to do the navigating so the master t-an give suf
ficient attention to maneuvering the ship.
It's true that the master alone can do other work when traffic is light
and conditions good, but as soon as any one task requires more than pass
ing attention, it is necessary to coll'promisc the major duties of assess
ment and shiphandling unless additional help is available on the bridge.
It is not suggested that the merchant ship resort to having a horde of peo
ple on the bridge performing nonessential and redlllldant tasks, as is toe
oft.en found on naval vessels (and perhaps the latter will find they can op
erate more effectively if their number is significantly reduc~d). but there
should be one additional persor to compensate for the local knowledge
thnt disappeared when the pilot went down the ladder.
The ;naU. on watch continues to carry out the tasb that were being
done whi le the pilot was aboard, while the additional mate plots traflic as
necessary and navigates. The information obtained is passed to the mas
ter, who needs only to check the work oflen enough to be sure that it is
160 DE?ARTURI!:
being done correctly. ThE' additional officer should be the chie f ma te when
possible, since he i8 generally the most experienced as well as being the
one who will most benefit from the opporbmity to be involved as the ship
enters and leaves por:. T oo often the mar iner spends several years as chief
male, shuffiing pape1 s io the ship's office during arrivals a nd departures,
only to be promoted to m aster a nd thrust back into the world of navigation
and sh iphandling. By as3isting the master, the chief mate is gaining t he
knowledge required for that mos t. responsible of position&, and acquiring
the skills required to be an effective shipmaster and shiphandler.
The plethora of bridge equipment has not relieved the master of any
traditional tasks, and in fact :>ften creates distractions for the otl:er offi
cers so that essential tasks required by good seamanship are overlooked.
Any imprE:ssion that this equipment makes it possible to conn a ship with
a bridge team that is one third sma ller than the master-pilot-mate team is
illusory-bring an additional officer to the bridge until the ship is at sea,
clear of navigational hazards and traffic, so the master can in fact be the
shiphandler r a ther than the navigator.
Fig. 7-2. "Ya see, Miste r Mate, if you come up to &ea speed t :>o soon sh E:
may vibrate a li t tle."
COUnsE CAHD AND PASSAGg PLANSI"'\1
Fig. 7-3. The pilot. departs off Cape Henry. From an oil painting by
Maryland Pilot Captain Brian Hope.
COURSE CARD AND PASSAGE PLANNING
1Gl
The passage outbound should be as carefully planned as the passage in,
with a char t in the wheelhouse avai lable for consultation, courses inked in
with pertinent information labcled, and a course card made up by ~he mas
ter .
The course card minimizes distractions and allows the master to re
ma in a t the centcrline window to coon the ship. The pilot. is able to draw
t he chart of the port from memory yet ~arries a course card; how ca n the
master effectively coon the ship withou t one? Thl' card ~;hould contain the
reaches or ranges in order, wi~h the course, length of thE: reach, a nd turn
ing point at the end of each reach noted. This information can be put. on a
t h ree-by-five card and kept in the shirt pocket, eliminating the need for re
peated t rips to the chartroom to pick ofT each course. The shiphan dler can
then spend that t ime watching the tug at.d tow that ma} be crossing the
bow, while being more certain as the sh ip is brought to each new heading
that there will be no errors in course.
The course ca rd should be made up for the en li re run from the dock to
sea, not just. fur the purtion cfthe passage after the pilot has disemtarkcd.
This effort will be especially appreciated should a rain squall or fog set. in
midway to ~·ea since the master will need only to glan ~e at the course card
to check the h ~ading as the ship feels her way.
Too often the te rm "passage pla nning" conjures up the vision of
mates laying out pages of detailed courses , distance, navigation aids, and
.,
'•
162 DEPARTURE
estimated runs at various speeds. This is fine for voyage planning, but a
i'orm-uast>d passage plan alone is not suitable for navigating in restrict~d
pilot waters. Indeed, a r.hiphandler working from pages of detailed infor
mat.ivn alone, without, m::~rked up charts a.td a proper course card, is much
like :!n actcr readmg from u script during a performance. 'l'his is distract
ing. H lends to put mental limits on the mariner when eituations arise
that are not provideJ for in the original plan. Put complete ir.formation di
rectly on the chart and course card prior to arrival or departure to eiimi
nate the chance of err,•r inherent in transferring information from the
plan to the chart to the quarter•master while actually conning the ship in
traffic and restricted waters. A passage inked in advance on the chart with
turning bearingR, courses, and distances noted, together with the pocket.
course card, are very much a part of any proper pasaage plan.
With a proper plan, properly marked chart, a course card, and effective
bridge resource management, the mariner can give the maximum atten
tion to handling the ship. A more complete discussion of the course card
and passage plan can be found in chapter 12, and excellent texts on pas
sage planning and bridge resource management are included ir, the Bibli
ography.
ABILITY TO MANEUVER
Do not be too quirk to change to heavy oil when handling a motor ship that
can maneuver only on light diesel fuel, or to bring a steam turbine ship to
sea speed when this means that you cannot then reduce speed without de
lay. The pilot station is the wrong place to increase to sea speed, or to be
unable to stop or go astern on short notice, since at that point ships are
converging from all directions rather than moving in a predictable man
ner within a fairway or traffic scheme. The in bound ships are eager to get
into port, &re preparing to take the pilot, and probably are in the highest
risk location of the entire passage. Perhaps the haste to increase speed is
understandable, since those aboard want to get the ship to sea where the
routine will settle down and life will return to normal, but wait a li ttle lon
ger unlil traffic is astern.
YPs, contrary to the landsman'e opinion. the seaman does consider life
at sea normal!
CHAPTER EIGHT
ANCHORING AND
SHIPHA.!'JDLING WITH ANCHORS
I had no means of kl1owing that what i1.1d happened to
me was a manifestation of the sixth sc:u;t.! pllssess.:d by
every born seaman. You can train a man in navigation,
seamanship, celestial observation and the computing of
tide, current, speed, wind, and drift, and yet he will
never be a sailor unless, at the moment of truth when he
is forced into a comer from which there is no way out ex
cept by instant intuitive action, he unerringly makes the
right move.
--Jan de Ha rtog, The Captain
Too often a mate is promoted to apositionfor which, throug'• no fault of his
own, he is not ready. The principal cause of this is inadequate on board ex
perience, especially "hands-on" experience (or junior of{tecrs under the su
pervision of more experienced of[tcers. 'l'his lack of experience is especially
significcnt in the area of ship handling, including the conning of a ship in
restricted waters and the use of anchors, although it is important that such
experience be gained in all the shipboard skills. In an indw;try that oper
ates in an enr.;ironment alien to the novice, it's i1.zperatiuc that knowledgebe passed from one generation of seamen to the next if professional sta n
dards are to be maintained. The fine training schools and maritime acade
mies that sen·e the seafaring corr:.munity offer an excellent theoretical
beginning, but it is only that-a beginning. There is much that can be
passed to a new officer only by example or instruction.
Pride in profession, app.-eciatiou of the relative importance of t•arious
tasks, and v.cquisiciv'• o{that intanginle char Mpamtes the exceptional sea·
farer from the avera!fe-sea sense--can only be glt!aned by observation of
others experienced in IJiorking c..t sea. The planning and effort required to
give junior offic~:r:; onboard experience is cs important as any other ship·
board task and deserves the same attentiort from the seasoned master, mate,
or chief. Hands-on training ensures both better operating ships and a con t tll·
uation of seafaring traditions and fhills. Let the chief mate conn the ship
163
164 ANCHORING AND SJIIPHANDLING WI't'Il ANCd ORS
and pick up tlu> pilot; haue the second mate plan a cargo loading under the
supervision of the mate; on improve.
Remember too that maneuvering charactcriEtics are not static and a
particula r loading condition such as a very light draft, or greater tha n nor
m al drag, or reduced undcrkeel clearance, may significantly alter a sh1 p's
n ormal behavior. Some ship types are more afTccted by these cha nges
th a n others: a high-sided ship or a heavily loaded ship may handle much
difTerently in strong winds than in light airs, and a loaded tanker i ~ a con
s iderably diff~:rent shi p from a tanknr in ba llast. s:lips cha nge, conditions
cha nge, and the weather changes. so don't fall into the tra p of trying t0 de
th e j ob the same way every time. Each anchoring i:; a new task : pla n ac
cordingly.
A bow thrus ter sig-nificantly changts a ship's handli:16 charactens tics
during ma1.euvers al slow speed in a n anchorage. Ma neuvering is simpli
fi ed if the thruster is u:;ed to turn a sh ip lo her final heading, set u p to
back, position and hold the bow, and periorm lhe other shiphandl ing tasks
\
166 ANCHOFING Ai'ID SHIPHANlJLING WITH ANCHORS
as the ship go~::s to anchor. Most ships do not have bow thrusters, though,
and thrusters h that task. Any
good seamanship book dir,cusses the first phase fully, so there is no point in
repeating that discussion. The assumption is made here thd th~ reader is a
knowledgeable mariner who is aware of the seamanship aspects of anchor
ing and has already correctly plannedthat part of the evolution, so this
chapter will stress primarily the second, ship handling phase of anchoring.
ANCHOR IN STEPS
Keep the si:liphandling phase of anchoring simple. Look at anchoring as a
series offour steps: approach, placement, laying out, and fetching up. Plan
each step separately as a series of small basic tasks rather than trying to
plan the entire anchoring as one long, complex evolution and think ahead
of the ship so each step leads more smoothly to the next.
A ship might need to enter an anchorage, reduce speed, back and fill
aro\1nd to thad, to windward or upstream, of other ships and ob
stacles.
Both ships with large sail areas and common :;hip types at light draft:;,
moving at slow speeds in an anchorage, may be difficult to turn to wind
ward when strong winds retard the bow's upwind movement. It is oft.cn
better to back and fill the "long way around" t.o a new course, backing the
ship'::; stern into t..he wind, if the bow won't come through a strong wmd di
rectlyoiler, ~he master stubbornly fights the
wind, repeatedly working the engine full ahead and full astern to bring
the bow through the wind, forgetting that the longe~t way around is some
times the quickest a.nd safest when maneuvering in adverse conditions
(fig. 8-l).
There will be times when winds and currents arc so strong that even an ,
expert shiphandler cannot maneuver to Lhe final heading before letting
170 ANCHORI NG AND SHI PIIANDLING WITH ANCHORS
F ig. 8-1. 'I'u.."'l the long way around in strong winds.
go, yet it is under these very same conditions that a master most wants to
be on that headillg to minimize the strain on ground tacUe and ship's
gear. Put down one anchor and a shot or two of chain and turn on the a:t
chor under these conditions, as described further on in this chapter, or call
for a tug, or stand off until conditions moderate. Consider these alterna
tives well before arrival at the anchorage, not when the situation arises, so
contingencies can be arranged in advance.
DEPTH OF WATER
Shallow water affects the ship's maneuverability. As the depth decreases,
the ship's tact-ical diameter increases and she becomes more directionally
s table. The sl:ip may need as much as twice the room for large course
changes in shallow water as she would in deep water, so it becomes in
creasingly important to approach a shallow water anchorage at slow
speed, in a position to back and flll to assist in turning the ship as re
quired. Remember also that the ship will twist somewhat more in shallow
water whil.c going astern during a maneuver. Mentally review the section
on shallow water effects while going astern duringthatmaneuve1·. Review
the section 'Jn shallow water effects in chapter 1 and figure 1-7 for a more
detailed aiscuss10n of these changeF;.
Deep water also affects anchoring because the anchor has to be put
down differently in an unusually deep anchorage. In depths greater than
about 100 feet the brake may not be able to stop the chain if the anchor is
let go from the hawse, because the chain's vteight and the mom~ntum de
veloped as the anchor and ch~in free-fall that distance ext::eed the capacity
MANEUVERINU HOO~I 17 1
of the brnke. The anchor should be walked out in such deep anchorages by
engagi ng the wildcat and backing the chain out of the locker using the
windlass. lowering- the awh"r nearly to the bott ::,nt ~efore disengaging tr.e
wildcat, and let ting the anchor fali free the last few fa thoms to the bctt.om.
Du ring these operatioll::l the shiphandler mus t hold the ship in positior. for
an cxi.cnded period o( time, even in s trong winds and currents, a task
made easier if the ship can first be brought to her final he:;.ding.
MANEUVERING ROOM
The number and location of ships at anchor , nearby shoals , a Ice shore,
and other hazards to navigation limit mancuvering room and make it
more difficult for a ship to enter, mancuver in, and depart froM an anchor
age. The shiphandler has to make plans that match the ship's maneuvcr
ing cha racLeristics LO the a vailable space in an anchorage, adjusting his
game plan to the size of the playing field.
Consider all options before entering so your ship and crew are pre
pared for whatever is required; once again, don't hesit'lte to mancuz.:er on
the anchor if there isn't erwugh space to tum or back and fi ll un assisted. A
tug can be ordered to assist your ship when mancuvering room is limited,
but a shiphandler who is reasonably skilled in anchor work can usually
turn and position the ship without a tug.
On occas ion, there just isn't enough scaroom in a crowded. or small an
chorage to turn to the fmal heading before lt.tting go, and there w11l ~no
option but to let go, heading with or across the wind and current as dis
cussed later in this chapter. Adjust anchoring plans to the real world when
you arrive a nd find the anchorage smaller or more crowded than ex peeLed;
use your shiphandling skills to adapt thl! ship's maneuvering ':haracte ris
tics to the mancuvering room in the anchorage or- iftherejust isn't enough
room-don't go. Even the handiest ship may, under som~ circumstances,
have to anchor elsewhere or stand oil and wait for conditions to change.
Maneuvering room is as much a considera tion when leaving an an
chorage as it is when arriving. There may not be enough maneuvering
room to turn and depart from an anchorage, even though ther!l wa:; ~u.ffi
cient room when yuur ship arrived. Other ships m a:• a nchor a fter yours, or
your ship may swing to a new heading so there is no longer sufficient room
to turn and depa rt. The same tcchuiqucs that arc used to maneuver at ar
rival- including backing and filling, using wind and current to ad,·an
t age, heaving short and steaming around on t he anchor, or turning .,.,;th a
tug-can be used to turn a shi p departing a small anchorage.
172 ANCHORING AND ~H I PHANDLING WITH ANCHORS
BRIEFING OFFICERS
Discuss the anchoring plan , including the intended approach and the loca
tion for letting go, with the mate on t-he bow. the matan abcar.1 reference visible to the ship
handler , together with a minimum of fixes aPd some shiphandling skills,
arc more than sufficient to position the ship as accurately as the often rc
c.lundant distance circies and continuous cross bca nngs that a re too ot t.cn
relied u pon while going to anchor. Quite simply, it i ~ a matter of profes
sionalism.
FINAL HEADING
The term "final heading" has been used several times in discussing an
choring plans, but just what does the term mean and why is it important?
The final heading is the di rection in which a ship ,~;lllie when at anchor
F.g. 8-2. "Aren't you overdoing this 'navigr:tc by eye' business, Jerry?"
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174 ANCHORINI.i AND SHIPIIANDLING WITH ANCI!ORS
heading into ~he resu ltant of all external forces, primarily the wind and
current acting on her superstructu re and underwater hull, after the a n
chor has fetched up and the ship has swung Prou n d to bring a ll thos~
forces inw eq\!i l:brium.
There an:: several reasonu why it'l3 better to let go wh en the ship is on
her final heading, and t he advantages of doing so more tha n compensate
for any additiona l time spent ~r.aneuvering to that h eading. When the a n
chor is let go lln tne final heading
1. The chain will lead clear of the hull as it's slacked out.
2. Wear and E..train on the cha in, stem, win dlass, and the mate's pain~
budget a re minimizec.
3. The chain is laid .:>u t along the bot tom neatly and quickly.
4. The ship can be positioned among other ships and obstructions
without concern about swinging clear after the anchor fetches up
since your vessel is already on the same heading as those ships.
Th e more res tricted or crowded the anchorage, or the stronger the
wind or current, the more important it is to anchor on this h eading.
In some instances it is essential to anchor on the preferred heading.
Large bulbous bows can be damaged by a chain leading under and
a round the bulb with a heavy strain and, even more importantly, the
chain itself may be damaged in such circumstances. Naval vessels often
have sensitive sonar domes and other equipment protruding from the
bow that can be easily damaged by the chain. Heavy winds, swell, and
strong currents exacerbate the problem as the chain works and surges
mor e heavily a gainst the wildcat, and the stem, bulb, and any protruding
ship's gear.
Obviously, it isn't always possible to maneuver to this final heading be
fore letting go, especially when the anchorage is small or crowded, or the
win d or current is quite strong or from the wrong direction, or visibility is
restric•.ed. It isn't always necessary to do so either since a ship ruay anchor
on any h eading in light airs or slack water-in a calm, every ship in the an
chorage probably lies at a different heading anyway. A real professional,
t hough, tries to bring the ship to her final heading before letting go in even
a light bre~::ze or weak curr~nt and, in practice, a reasonably skilled
shiphandler is usually s uccessful in doing so. There are methods for an
chorir.g to minimize the strain and problems wh en it is impossible to let go
to the fina l heading, and they are discussed later in this chapter .
ANCHORING On ' TilE 1-'JNAL HEADI NG 175
How is the final heading determined? Lused ahead and
astern us needed to maneuver without concern about being ov~r speed
when the final anchoring location is reached.
Detect your ship's movement over the bottom using the apparent mo
tion between other ships or objects in the anchorage and more distant ref
erences a float and ashore. Closer ships appear to move across , in front of,
background r~ferences because cfthe differences in perspecti·1e between . I
c:
0 "' c 8
.!!! "0
'3 c
"'
.,
"' "0 a: c
~
'!'liE APPROACH
~-',{ ® ........ ___ _
Wonc:tcurrcnt astern
1. Put down s•arlloau.J ed. fie ca reful, though,
that speed isn't signi!i.:.antly incrca.,.,d b:, ,ucce;;si, 800 feet from thf> st~rn. Pllt the bow, U0t tlte bridge, whare
you want. the anchor to lie before letting go.
Do not routinely anchor in the middle of an open anchorage, so far from
other ships and obstructions that you swing clear by several ship lengths
no mat~r how the wind and current migh":: turn your ship. It is un
seamanlike to wa.>te space in the anchorage; it causes problems for other
ships anchoring after yours and it also causes problems for you, since
other vessels are forced to anchor closer to your ship than might be safe be
cause they have to use whatever space you leave. It is also unnecessary be
cause most ships swing to new headings at the same time, staying clear of
each other, unless tneir draft, freeboard, or size are so different that some
swing before the others. So there is no need to, at all times, be able to swing
clear over an arc of 360 degrees.
Anchor only as far from other ships and obstructions as necessary for
your ovm ship's safety and put the anchor closer to ships ahead than
astern. Your ship lies backfrom the anchor and the ship ahead and, as the
ships turn to current or wind, the ship ahead swings away from you. ~n
print, Lhat may sound like common sense, but it is amazing how often ex
perienced masters and pilots put the anchor in the center of an open area
and fmd they are anchored too close to ships astern when the chain
stretcheu out. This can be an even greater problem when the tide or wind
changes and the ship astern becomes the ship ahead. Place the anchor
closer to the ship ahead, not in the center of an open area, when letting go
(fig. 8-5).
Think ahead of the ship as you place the anchor. Set up to back and
maintain control at all times when the engine is going astern. When an
choring a ship fitted with a right.-hand turning fixed propeller. under most
conditions, on or near the final heading, kick the engine ahead ' vith the
rudder hard left to start the bow swinging to port and then put the engine
astern. Back until the quickwater reaches amidships and then continue
backing until the ship starts moving astern. Ideally. wh.m anchoring close
to thP final heading, the bow should steady up as the engine goes astern if
the starboard anchor is to be dr0pped, or begin swinging slowly to star
board if the port a:~chor is to be used. When anchoring at some large angle
away from the final heading, the bow should be swinging away from the
anchor, an the chain pays out, as previously described in the section "Final
Heading" in Lhis chapter.
Flooo
Flood
LAYING OUT TilE CIIAIN 181
a ---·--. ----c=J (;\ ...
• \V ' • _______ •• J
Ebb
Incorrect: Anchor le I go [l midway between ~htps
(2 .. -i2\"·-·; ,r--,
·--~-- ---··' --'-...____.-)
Correct: Anchor le I go
closer to sh1p ahead
Ebb
Fig. 8-5. Anchor closer to ships ahead than astern.
.
Masters too often stop the engine when Lhe quick water reaches amid
ships be•.:ause the flow ofwatermovingup the ship's sides c1eates the illu
sion that the ship is moving astern when actually she is then just c..lead in
the water. The chain will only pile up on Lhe bottom and stop running out if
the anchor is let go without some sternway. Continue backing until the
quickwaler is forward of amidships so the ship is moving astern, open the
brake, and let go.
LAYING OUT THE CHAIN
The brake is tightened and eased as necessary to control the chain as the
ship moves slowly astern, laying the chain evenly over the bottom rathe r
than ir:: a pile that could foul the anchor or damage the gear as the sh1p
falls back, until the chain is brought up tight against the anchor with a
heavy strain.
The mate on the bow must keep the bridgr. inf01·med of the lead and
weight on the chain at this point. The mate is the master's eyes as he ma
neuvern Ll move Lhe ship slowly astern at the be:;l speed and heading.
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182 Al'JCIIORING AND SHIPHANDLING WITII ANCHORS
keeping f\ light s t.rain on the chain at all times so it is laid along the bottom
clear of the stem and bulbous bow. The mate notifie'l the bridge as soon ns
the ordered length of ch:1in is out so the engine can be put nheao to reduce
stern way, if nf!cessary, before the anchor fetches up hard. EvP.ryone gets
back to bed much ::;ooncr if the mate keeps the bridge well ir.formed with
out having to be repeatedly asked how the chain is leading.
Tighum the broke enough to check the chain and control it, but don't
set the brake so tight that the chain is held and the anchor flukes dig in
prematurely. When the flukes dig in too soou, befo1·e the shank is nearly
parallel to the bottom, the anchor may break free again- ·so balled with
mud tLat it can't dig in when the full scope of chain is out. This is less of a
problem when the anchor is intentionally dragged, because it is less likely
to hav~ dug in so fully that it comes free with mud and rock jammed be
tween t!.e flukes and shru1k.
Keep in mind that it is movement over the bottom that's important
when letting go, not speed through the wa\.er. When drifting with a strong
current from ahead, the ship will have sufficient stern way over the bottom
to lay out the chain when the quickwater reaches amidships, since she
would then be moving over the bottom at the speed of the current. Obvi
ously, if there is a 1-knot current from ahead and you back until the water
is midships, you will be making 1-knot astern over the bottom and the
chain will lay out nicely.
The aforem:mtioned apparent motion of ships at anchor relative to
backgroi...Dd references afloat and ashore is the best indication of ship's
movement once the ship starts moving astern. The quickwater forward of
midships c.nly tells you the ship has sternwuy, while the Doppler log often
becomes useless once the quickwater moves up under the hull. Watch the
movement of vessels and objects against the background shoreline a:1d
move the ship slowly astern over the bottom.
DIGGING IN
Tighten the brake when the required amount of chain is out and, if tl,e
ship still has significant sternwRy, put the engine ahead one last time so
the chain isn't parted due to excessive stern way as the anchor fetches up.
You might use hard-over rudder while kicking the engine ahead at tl}is
point, if required, to bring the ship clos-:lr to her final heading and to keep
tne anchor chain clear of the stem, bulb, and any underwalcr gear. Re
nembl!r that the rudder directs propeller thrust, and the stopping effect
as the engine turns ahead is m.1ch greater if the rudder is amidships.
SWING INO HOOM A1' ANCIIOH
The !:!ngine is used ahcnd only long cnou~h to reduce strrnway. Don't
stop the ship completely. Hold the chain nnd let the ship movr sluwly back
ngaim:t the ancl,or ::.> the cat.cnary caused 0y the ch11ie·s weigi1t absorbs
most. of th~ force of the rcmainir1g stem way. The ship must have a bit of
stern way to work against the anchor aud dig the flukes well in to the bot
tom. Back the engine again, if the ship inadvertently stops t.oo quickly, so
the anchor is well dug in before the engines are rung off.
'
SWINGING ROOM AT ANCIIOH
Obviously, masters prefer to anchor far enough from other ships and ob
stacles, space permitting, to swing clear on bolh the present heading and
all other possible headings on which the ship might later lie nt a safe dis
t ance from other ships.
But how far are you from ships ahead and astern? In a crowded anchor
ag~. especially after days in the oven ocean, other ships always look closer
than they actually arc due both to your height of eye and to the lack of vi
sual references wit.h which the distance between ships can be compared.
Even P.xpe"icnced pilots arc often surprised when, afler anchoring a ship
in what appeared to be close quarters, th:!y get. into a launch to go ashore
and, from a more distant vantage point close to the water, look back to find
that the ships actually are quite far apart. Unfortunately, the master and
deck officers are rarely able to view their vessel from a launch, but they
can walk down to the main deck when: the true distance between ships be
comes :mmediatdy npparr.nt. Try this the next time you arc concerned
about the distance between anchored ships.
It is sometimes difficult to actually measure the distance to othe r
vessels anchored close to your ship. Radar, while excellent. in open an
chorages, is often less effective for measuring absolute distance be
tween closely anchored ~hips because it measures dist ance from your
radar mast to some not always definable poin t. on the other ship, to an
accuracy of fractions of a mile, not yards or meters. Stacks and ship's
gear also obstruct the radar and r.hips anchored ir. those olind areas arc
not visible to !.he !"ad~r e t a! I Racar is u;:uall:r mort:: ht:lj.Jf c~i to dewcr.
changes in distance, such as when one ship or the other drags closer or
farther a way, than it is to measure absulute dis tance between ancho;·ed
ships.
Estimate distance from other ships by eye using yourship's length as a
reference and measure the distance from oUv~r ships ahead and astern to
your bow or stern, not to yo•Jr location on the bridge. '
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184 ANCHORING AND SIIIPHANDLING WITH ANCHORS
Some pilots swear :.hey can estimate distance more accurately by bend
ing over and looking hetween their legs. Pilots and seamen oflen joke
about this technique hut, quite frankly, it Reems to w0rk. It's probably
better to try it without an audience, though, as shipmates may think you
are a bit ctrange, standing bent over looking between your !egs at ships
forward and aft, but it helps-so bend over and look.
It may be necessary for a ship lying at anchor in a crowded anchor&ge
to maneuver on the anchor using the engine, rudder, or bow thruster if
available, to swing clear of other ships as she turns to a new tide or a shift
in the wind. Calculate tide and current changes and watch the weather
and oth~r ships closely. Have the engine and thruster ready well before
the calculated change and, in a particularly restricted anchorage, have a
I
Fig. 8-n. "He says things look better that way."
:'-IOOHING AND ANCHOH!NG W!Til TWO ANCI!OHS 18.)
tug ordered :\nd standing by to assist in turning. Don't W!!il until the other
ships start s·.,inging to make these preparations.
The mastE.'r m a~ also decirie to ;>ut -:!owr. rw~ a1 • ..:hors in,, sm .. ll an..:hol
age to limit the ship's s· .... ing. Mooring tot\\ o anchors may be lhe best ac
tion under some circumstances and common methods for doing so arc
discussed later in this chapter.
It may not always be possible to moor to two ru~chors in a crowded an
chorage if other ships close by are riding Lo one anchor. They will move m a
wider circle and your ship, restricted by the second anc:1or, may not swing
clear. Either use one anchor, or be ready to maneuver or to heave up the
seconcl anchor if other ships start swinging toward you in such circum
stances. Local practice is important, since all ships will generally follow
the custom of the port when anchoring or mooring so that all ships swing
together.
MOORING AND ANCHORING WITH TWO ANCHORS
Any number of seamanship books present the reasons for mooring and an
choring to two anchors, so this text will briefly discuss only the ship
handling nspects of these evolutions.
The running moor is a maneuver for putting down two anchors in line
while the ship has headway. The ship is brought to her fmal heading,
stemming the current and wind, and the fi.Tst anchor is let go. That chain
is slacked as the ship continues moving slowly ahead to drop a second an
chor. The first chain is then heaved ir. as the second chain 1s slacked so the
ship drop:; back to ride between both anchors. The two ar.chors can be laid
along the axis of a channel or in line with a current so the ship rides be
tween and swings within nearly her own length to each turn of the tide.
The running moor is sometimes called the (lying moor. The name is col
orful, traditional, and unfortunately misleading since it conveys an image
of an a.ction-parkE.'d, high-speed anchoring maneuver under something
less than perfect control. No competent shiphandler does a flying ar.y
thing and the term should be avoided. Walking moor might be a better
name!
The ship Ca::J ah:o anchor to two anchors laid vut ahead in a maneuver
similar to a running moor, as described in the section on five- anri
seven-point moorings in chapter 9, perpendicular to the wind a11d current
llSing the same or different lengths of chain to minimize yawing, increase
holding power, or hold a ship's head to a swell to reduce rolting- while work
ing cargo. A simila r method for anchoring to two anchors, for ships fitted
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I
186 ANCIIOHINO AND SHIPilANDLI NG WIT!l ANCHORS
Fig. 8-7. "1 thought shiphandlers never did a flying anything."
with bow thru~ters, is described in the section "Mediterranean Moor~ in
chapter !1.
A standing moor or ordinary moor is similar to t!1e running moor ex
cept the ship comes to her final heading, backs until she has sternway,
drops her first anchor, and slacks the chain as she maneuvers astern to let
go the second anchor. The first chain is then heaved in while the second is
slacked until the ship rides between the two anchors. The standing moor
is more commonly used to lay anchors in line with a CUlTent since the
shiphandle;- has less control of a ship when going nstern, while the run
ning moor witl-. s teera ge and headway is more cften used to lay anchors
perpendicular to wind and current.
Seamen are often reluctant to use two anchors for mooring or anchor
ing because of problems dearing round turns in the chain, se you may go to
sea for years wi thout mooring in this manner . Round turns are causo.; modi
cum of Sl'amanship and shiphandling skills. thcsl! turns en•• be prevented
by fuming the ship in the opposite dtrt!.:!ion at r:ach tum of tht ~id. o.
change in the wind (fig. 8-8).
Tum the ship by putting the mddcr hnrd over anti Kicking the engine
ahead as needed, or have a tug p~sh on the quarter or tow the stern around
on a hawser. Start the ship swinging in the prefen-cd direction, putting the
current or wind on the proper side so 1t too pushes the hip around alt.cr
nately clockwise and then countcrclockwise on suC'cc:ssive ti des. Seamanship
texts also discuss can ling the ship using hard-{)ver rudder, but the ship's en·
gine or a tug is usually more reliable and effective in turning :.Oday's larger,
more diverse ship types, which may not respond to the rudder alone.
Mooring to two anchors may be the best way to anchor under some cir
cumstances, in spite ofpotl!ntial problems with round turns in the chain,
and every seaman should know ]v)\v lo prevent round turns and how to
clear them if they do occur.
STERN ANCHORS
By Captain Warren G. Lebach, Master Mariner
Stern anchon are most commonly found aboard the great n umber of nu val
landing and assaul t vessels built during and since World War 11. 'l'hcse
anchors give an added measure of vessel control, prevent broaching uuc to
wind, swell, tide, and current, and arc used to kedge ofT a beach.
Flood
' I .... :"""~
,-,r"' :
/ /
/ /
I I
I I
I
..-"
I I
I I
I I
I
Fig. 8-8. Prevent round turns when moored.
Swing ships moored to two
anchors 1t1 !he oppos110
duechon lo consecuhve t1dcs.
Et.b
I
188 ANCHORING AND SIIIPHANDLING WITH ANCHORS
Stern anchors prouably came into use shortly after man put to sea.
Kedge (stern) anchors were used to hol d a si tip of the line in pvaitior. to pro
vide a steady platform when bombardir~ shor~ batteries or vp~v.sing
fleets in numerous naval ~f\ttles curing the '>ixteenth through the eigh
teenth centuries. One of the more memorable naval en~agements in which
stern anchors were used was the Battle of the Nile where Admiral Nel
son's Mediterranean fleet caught the French fldet at anchor in Akubir
Bay. Nelson divided his fleet int.o two columns, ran down both sides of the
French fleet and, using kedge anchors, positioPed his vessels so they could
pour deadly broadsides into the opposing fleet .. The outcome changed Na
poleon's plans to advance into the Middle East.
Unfortunately, few merchant vessels ot!-ter than those designed for
specific trade routes are presently fitted with stern anchors, so only a
iimited r.umber of masters and deck officers have had an opportunity to
use them. As with any gear that receives only limited use, there are nu
merot~s theories about the use of stern anchors-some correct and many
incorrect.
A few steamship companies, including Grace Line, Inc. and El Paso
LNG Company, fitted their vessels with stern anchors. Grace Line fitted
their folli:'hard r ight. I t will be immediately apparent as Uw ship rnO\'cb
ahead that the turning di ameter for this accclcrallng turn is significantly
less than for a turn using con:-;tant revolu tions, nnd most ships will tu m in
about half the diameter requi red for the hard right turn nt 6 knots, assu m
ing both turns a rc made in the same depth uf water (fig. 1-4 ).
W ater depth vessel is allowed to develop (fig. 1-5).
Again observe the diameter required to make this turn, a nd get a feel
for the mnne u ver nnd the time required to r educe headway. The efTcctlvt·
ness of t he r udder while the s hi p is going a stern can a lso be ancertaincd at
this t im e .
D o no t. be fooled by the fact tha t , during both this backing and fi lling
m a neuver and the steady state turns, the ship at first develops a E,ood
swing and then appears to be losing that swing as the rate of turn :iv
creases. This efT eel is sometimes misunderstood und the s hipha ndler feels
th a t the sltip is going to stop swinging. The rate of turn will only decrease
1. Half ahead/hard right.
2. Half asterrv'hard right.
3. Halt asterrv'hard left.
4 5. Half ahead/hard right .
6. Turn completed.
'--::::--...
-~~
_____ ..... -~
j!-J...,. .. ~ ..... ~ -_-____ ..,. _ _ 7/
--~"""..:::::1..::/. _ _ _ :::r._ ~
'·'
Rr pcat 2. 3. 4, and 5 as required.
F ig. l-5. Back.ng nnu lilliug maneu ver .
IIAI.F AS TE ltN TO DEAl> 1:-.1 T ilE \'.',\TI: H I :J
u ntil the forct!S u!lccting the s hip r each o stalt• of t!qui libnum, after which
a consta nt rate of turn is 1naintained. D pa t ient!
Do nut. [1\.LCntpt. to hack nud fill to the le t'; unless yO\ .. h ove no olht: r a l
ternati VL', as a :.hip will normally lose her swing in that dirccticm wlwn t lw
en::inc Rtar·ts turning as t::rn. An excP.as ive uumbcr ol cnguw mancuvt•n;
ore requi red to back nnd fill t.o the left , anJ in many Cils c:!s the ship Rim ply
w ill not make the mhncuvcr. Some ef the u Res vf the bucl,ing aud fi lling
n::meuvcr arc discussed in later sections.
Ther is not much point in collecting data during this n,ancuvcr. The
rote of turn nncl the t.um ing diameter requirce to reverse the vc-;sel's
heading are more a factor of the shiph a ndler's skill than the sh1p's ch arac
ttJristics , '>0 comparisons are net particularly meaningful.
HALF ASTERN TO DEAD lN THE WATER
The ship's behaviorwhen backing con only be learned by observation. It i~ aboard
must have a feel for if they arc to mnncuver their ship properly.
While proce eding at 6 Lnots put the cngin~J half a ::> tern and the r ud
der amidships. Do nothing fu r ther except collect rr.
68 o.Jcgrccs
14 AHH!VAL
compared to deeper water, there i ~ not much difference in the stopping
distance required. The data collected during this mnneuver arc useful
both for r outin e and em>..crcise trwl yields iitt.lc quantitative data.
now A:>~D S'I"I:IU\ Ti!!'.,_.sn:w;
Keep in mind that botlom con!ig•11 at101. and the pro:\llnily of a hank nf
fcct this maneuvcr. A ship may back Mth.: wrong way," especially 1f! hl•
s tarl;o;;nl quarter is close to the i.Jank or a shottl area at till' 1:tlgc of th.J
ehanncl, so that the swing to the letl is not checl-. .:d. This efl~cl 1s mini·
mized if the ship is kept nt or near midchanncl wh..!n backed.
These possible variations in ship's beha\·ior make shiphanriling intSanta Lucia class vessels, thtir post-World War 11 C-2s and
their C-2 combination passenger/cargo vessels with stern anchors. Th P.
anchors were used to keep the ships in position while lying at anchor in a
number of open roadsteadR along the west coast of South America.
El Paso LNG Company fitted their nine liquefied natural gas vessels
with stern anchors. These anchors are to be used in the e"ent of either a
rudder or engine failure to slow the ship and give directional control and to
make it possible to anchor these large ships in the Cheoapeake Bay and
the narrow channels of the Savannah River. They are of sufficient weight
and are equipped with the amount of chain needed to hold t:1e 950-foot
ships in the strong flood and ebb tides found in these areas.
When using a stern anchor
1. The master must have confidence in his sh1phandling ability and
understand the &tern anchor's uses and lirilltations.
2. The mooring maneuver must be carefully planned in advance aud
put. on the chart with three predetermined reference bearings lai-:i
down.
3. The rnaneuver must be reviewed \vith the other officers so they are
thoroughly familiar with the plan and its alternatives.
STEHN A~CIIORS 189
4. The steering gear and engine must be used j ud iciously, especially
once the stern anchor is let go.
5. T:u o:.:ghout the maneuver the u1as lt:r wusllhiuk ahead of the ves
sel and adjust for chr..nges in wind 1111d current.
ThP.rc is a significant risk of damaging the rudder and propeller wiLh
the stern anchor and its chain because of tile stern anchor's locatiOn. De
certain all slernway is off the ship before letting the stern anchor go. Limit
stern way when heaving up so the chain leads af: with a light strain at all
times-the ship must not overrun the stem anchor-and wait unlillhe an
chor is in sight and clear before putting any headway on the ship.
In an open roadstead both bow anchors and the stern anchor are laid out
in a "Y" pattern to form a three-point moor. The mancuvcr is straightfor
ward. Aficr all planning and preparations for mooring ha vc been complet.cd
1. The ship begins her approach at the minimum speed required for
stccrageway.
2. The moor is made, scaro:>m pern1itting, with the bow to seaward.
Approach from sea to the left oflhe intended moor to take advantage
cftliL ship's abHity to back and fill to the right. Make the approach
as wide as searoom allows.
3. Come up to point "A" as shown in figure 8-9 so the three predeter
mined bearings intersect.
·a·
' ' ,
' ' '
'
'
' ' '
·c·
I " I
I : !
' ! ! :
Fig. 8-9. Mooring' with a stern anchor.
,
;
; '
·o·
'
'
190 ANCIIOHIN,; AND SHIPHANDLING WITH ANCHORS
4. Proceed down the reciprocal of bearing line "B" with the port anchor
backed out and ready to lnt go. Back down as the ship noflrs the dn>p
point, take all headway off the ship, and let go the p'>rt anchor.
5. Eack t.he ship sil)\'lly along the recipro::al of bearing line "B" and
turn her to bearing line "D."
6. Come ahead and proceed slowly down the reciprocal of bearing line
"D" while keeping the port chain slack until the drop point for the
starbo:\rd anchor is reached. Take off all headway &.nd let go the
starboard anchor.
7. Back the ship to point "A" while controlling the ship with both an
chvrs, then continue backing along bearing line "C" to the drop point
for U:e stern anchor.
8. Mn~{e sure all a tern way is off the vessel so the ship cannot override
the anchor and chain, and let go the stern anchor.
9. Reeve the bow anchors while slacking the chain aft until the ship is
riding to all three anchors and the three-point moor is complete.
To unmoor, slack the bow chains and heave the vessel astern using the
stern anchor. Bear in mind that you must pay out the bow chains slowly to
Fig. 8-10. "I got ten shots out, Cap', and she seems to be taking a strain.~
TilE ANCHOR AS A Sllli'IIANDI.ING '1'001. Hll
contrr.l the \'esse!. (Remember, you must not ovt•rrun the stern ancho•·.)
Wait '.lr.lil the stern anchor clears the water and is in sight before moving
the ship ahrad. Heave both h"w chain!: .si..mlt:mer.usly u•itii puiut ·A'' j,
reached, and d1s~:1gage the starboard chain. Continue tu heave on the !JOrt
chain until the !:hip reaches a positiOn approximately halfway between
point "A" and the pc,rt anchor drop point. LCollect thl' usual data and nole particularly the din·ction of thl• wind
relatiVl! to the ~hip. Sine
Lot:ated at the t•xtrcmc end of the vcs·
!Wl for muxmJUm efTeclivencss.
Avuilnblc at all l imes, unhkc u lUg.
Givt>:i gonllf!
Canuo• be UIH:d to d vt•sscl when going n~lcrn, hold the ship along-, id bc
cunH:s casith e ship through a series :Jf "Z"
maneuverA.
A vesst:l can huve positive, negative, or neutra l d irectiona l st.abiltty. A
sh ip t.hall:AL STALIILITY 19
directional stabtlity. If she swint:s at incrca~ing rnks of turn wht'!l the
rudder is :\midship}1 };he has negali\c stabilit.v. A VC'SSP.! with nett!rn! di
rectional stabtltty continues swinbring ~t till' present ;-ate, or contir ..... ,.,
a long on her currc!lt heading until e;.;tcmal forces tahe c!Hirg" Sitcl hv
even small changes in tnm. A few feel of drag will change the entire po.: r:
sonality of an otherwisnlurning Iter ovPr Lo n Jll•ot
ifsLPering bC'hnvior is eonsidcrC'd to be a func-tion ofdircctioHal !'la:Jtltl y
11erausc the changes tn di rectional stability arc ~ignif~cant as liralt
a nt!tril!l arc altered, and because large, full bodH•d Hhips wi~h large block
cocflicienll; oflt>n squat by the head, it is c•sJ>ectally important that lhl'~ c
20
------- --
Fig. 1-8. uA few feet of d rag ch.mges the entire personality 0f n s~1ip,
Cap' . ... "
potential chang.:!s be given careful consideration when trimming such
ships for ar rival.
It 1s apparent then t hat direclional stabil ity
1. Increases as the und·~rkeel clearance decreases.
2. Becomes more pof-t if ive as length increases.
3. Becomes more positive as drag increases.
4. Decreases as th£. block coefficient increases.
5. Decreases as the beam .ncreasC>s for a given length (length/beam ra
tio decreases).
6. Decreases as the arPa of the forward sections increase" relalt,·e ~o
the nrt';; .lf the RflE•r seclwns (as the p1vot point shifts ahead).
EFFECTS OF llO'ITOM CONTOUR ON HANDLING CHARACTERISTICS
Changes in ocem1 botto111 ''ontour do not a fTectthe ship's henavior until
shallow wnter conditions are encvuntered. Shallow water effects as shown
in figure J-7 vary m magnitude with change!. m auerage depth.
EFI-'I.(.'T::, OF 1101·ro:-.1 CONTOUH CJlliiA;.IIli,J~;c Cll .\llACTI.HI STJCS ~~ }
The :1dditional efft'cl« of .:;pecific changes iP bottom contou1 arc supl!r
imposcc o.1 these shallow wntcr effects and causl· (fig. 1-9)
1. The ship's bow to move away from more ~hallow wnlcr. This ,,.,,11-
known "Lank cushion~ effect is caused by the pressure hu!lt up on
the area of the bow, as seen in the ra1sed water that iorms between
the ship's bflw and the shoal or bank.
2. The ship to move bodily sideways toward a nerby shallow arua, a.
her parallel midbody passes that area. This mo·tement is caused bv
tlw 111crea$c in velocity of the water Oowing through the restncted
area between the ship and shoal, and the resultant reduction in
pr£>ssure on that side of the ship.
3. The stern of the ship to move toward shallowe·· areas or bnnks due· to
the reduced flow of water to the aren behind the ship, and to the
ship's propeller (J!l the side closer to that shallow art'a.
Uank l'u~hion is unfortunately oftl!n exaggerated in marine texts that
describe hypothetical ships "smelling" shnllow water and heading aw:lv
from il, s11ving themselves from grounding. 1'hcs~: tales nre untrue and
dnn~crously 1ni:sleading and should he fih'd along with those about sea
monsters and fall:ng ofT thee ige of the world.ll i;: more C\lrreci to say that
"a ship tends to 11C'nd away" from shoal water-the effect is not as si rong- as
ofte:n indicated in classic books on seamanship.
. . ·- .............. . ····· ... ............ .
(;) H (- -
r4~~~----~~------- ~
~~"~-----------------
... ... ......... ... ... ... 0 •••• • ••••••••••
Fig. 1-U. En·cctf' of chang(•s in bottom contour or a 11t•ar bank.
f
I
.t
22 ARR IVAL
Bank s uction is more strongly felt t.hnn ba nk cushion a nd caust•s n ::;hip
to sheer 11way from a :.hoal or bank. This is a significant. effect that can
mn ke s teering difficult ae the bot ton1 con tour changes in s hallow water .
All these effects r.r e fe lt to some degree dur ing the a rrival phase of a
voyage a~ water depth decreases. The effec ts a r c more p1onounced as the
ship rro.::ccds up a channel and arc diacuss ;:d mor t fully in applicable
chap ter;,.
JWWLING OF LARGER 3 HIPS IN SHALLOW WATER
A study was conducte d by a group vf shipping companies ancl orgnmza·
tions in July 1977, using Esso Osaka to determine the handling ch aracter
istics ofVLCCs in shallow wa ter.' This study has been widely circulated
and used to refine previous theories. The data were also used to improv!'
computer programs for the various shiphandling simula tors used •.o t rain
deck officern (fig. 1-10).
While mostoflhe in formation contained in the tcr•s is discu ssed in this
text, it should be stres sed lhat the tests proved that, contrary t o ofl-stated
opin ions, VLCCs remain highly maneuverable in s h allow water a nd steer
quite well both with the engine turning ahead and stopped. This now
well-documented fa ct, based on both the Esso Osaka s tudy a nd on the ex
periences of masters and pilo.s who have handled these la rger sh ips in
shallow wa ter, s},ould be comforting to the mas ter bring ing a VLCC into
sh a llow water fQr the fh·st time. In fact, large sh ips usually steer better in
sh allow water with the engine stopped th an they do in deep water. There
is no need for a ship to move at excessive speed to maintain steeragew.1y.
It is encouraging to see greater attention being given to real-ship/real·
time da ta on shiphandling and maneuvering characteris tics. The data col
lected during the Rsso Oscka trials, and severa l other shallow water t ri
nls, such a A th ose done by El P aso Ma rine Company with liquefied nAtural
gas carriers, cnn only r esult in c;afer handling of presen t vessels and the
desig n ofbette r-hanrltin{! ships in the futu re.
APPROACHIKG THE PILOT STATION
h should be standl\rdpractice to statwn an engi neer u, t!1e st. Prtng gear
flat when a r r iving and m aneuvel"ing in restricted waters. It's toe lAte w
send someon(:: to shin to the trick wheel a fter steering is lost. The engim.:cr
1 W. U. Gray, '!:sso Osaka Maneuvuring Triais.
Al'l'ROACIII:\G TII I; PILOT FfAT ION
Fig. 1- 10. The VLCC Rsso Osa/w. Courte:;y Exxon Corporation.
ass igned to stand by mus t be trained in shift i115 over lo the emPrJ.icncv :;vf'
Lem and then s teering by both compaAs courses and Ctlllning odcrA-. -
This operation must be practiccd at sea before an c t.1crgcncy nccd helmsman to Rler. r in a confined an .1
with no visible horizon, leL alone an untrained pcn;on under emergency
cc ndiLions with the noi ~;c of the steering gear machinery making it diffi
cult !o hear helm orders . Th e half hour a month rt'quired for practw.: i:;
Lime well spen t.
There mus t be a tes ted and reliable menns of commu nica t111g hetwet•n
the steering geor. rd and po1 ~
of the ba::;e course. Using this slcwiug mnneuver tlw ship lo!>cs et Slpl·fi
cant .lmount ofheadway each lime she swings, yet makes gnod her d r,; 11 ed
track t~Jward .:; the pilot station or anchorafie.
Keep in m1~1d when other vessels are abo1..t that th1s s1Pwin1; man.::uvcr
lliU} be coufusmg to them. They don't know if your chang ncadway and avoid c:tsualties both in the open sc-~t
and when mane t.vel'ing.
PICKl='lG UP THE PILOT/MAKJNG A LEE
As you approach tltc pilotstation af:.er several days steaming f.t sea s peed,
n com·cious effort is required on the part of conning officers to reoricrtt
themselves to the !ewer speeds nJcessary for maneuvering. When makmg
a Ice for tltl pilr)(, be s ure speed is reduced t.o 3 to 4 knots. There are ports
I'ICKI=-'G UP TilE i'ILOT/~IAKIN(, A I hf.:
with his:h·powcred boats and Sjh'rial bonrdin~ facilities wb•re it is pn'·
ferred that the ship procet•d at higher speeds. You arc usually aware of
thi:; rcq u i rem ell'. er the pilot wi 11 inform you cf 1 t >. i;t '.'!IF wh ~ :1 yuu ;::: 11
the stnt inn two hours before arrival. Unless infor111ed othcrwist•, llw
3-to-4-.-not speed is comfortable a.td ye I, not so slow that the boat ha;; cll!li
culty staying alongside while transferrin(~ the pilot t.o the ladde r.
Make your approach so as to give the pil01. a goc.d Ice and rcmPmber
that it is possible to knock down a short chop ~y putting a swinG on y 11w
ship just IJefore the pilot. boards so the 'lliCirter i:; swinginiJ atcc!y fnun the
pilot bont. WSwceping a Ice" in this manner is Lad you proceeded din•ctly and then slowed with
t lw eng1111~ alone. More importanl, while it may not. look rough from the
I I
\
I
~ )
' I I l
\
I i ~
I (/)
\ I -:;.
) ~
I \ ) )
Sea I I
Sl. ep: 11.'11 I I :orodol I
r I }
I
' \ \ t
:
•, - _;; ))
Fig. 1-l 2. ~hip 111 hard over turn "sweeps a Ice·• l"or tlw pilot.
28 AHHIVAL
bridge, it is rough down there in that small launch , and the tr:m~fer ':ill
often he hazardou~:. Professionalism demands that you make the sttuat10n
as safe as iJCSSihle for the pilot, regardless of how late you a re arriving at
the terminal, or how many gangs might be waiting at the duck.
To further assist in sweeping a lee wtthout gaining excessive headway,
you can use the pre\"iously described backing and filling maneuver. Come
ahead to start the ship swinging to the right and then put the engine
asten:. The ve:;sel turns about her pivot poin~ while headway is simulta
neously reduced so the maneuver does not require any great amount of
searoc.m. Remember, though, that all the way must not be taken ofT the
ship as thill makes it difficult for the pilot boat to stay alongside. It is also
important not to bark so long that the wash reaches the pil ot ladde r a nd
sweeps the p1lot launch away from the ship's side.
ESTrMATING SPEED THROUGH THE WATER
BY SHIP'S PROPELLER WASH
How, on a darl: night without a Doppler log, do you tell what speed you
are making? By watching the wash from the propeller. When the engim
is going nstem, the ship'A speed is down to about 2 knots when the wash
from the propeller begins to move •1p the starboard side of the ship So
long as that wash is being left behind the ship, you arc making som('
thing in exress of 2 knots. Of course, as every ~cam an knows, once the
wash reaches halfway up the ship's hull , the ship is dead in the water.
(See figure 4-2.)
Would you want a good, sound ladder to scale a two-to-four-story sway
ing building? The pilot wants at least as much when boarding your rolling
ship in a seaway.
Be sure a cie.J.n piwt ladder meeting current IMO and USCG s tandards
is properly rigged under the supervi sion of n licensed deck officer . This of
ficer mus t visually and physically inspe:ct the ladder as it is rigged and be
in a ttendance while th e l,ilot embarks or disembarks. Two seamen mus t
also br on hand at thflsc tim-"s. Use only a proper ladder, reserved for use
as a r 1io;: iadder , that is made up so that
1. The r .u~gs a rc of one piece h a rdwood.
2. The button• four nmgs a re of reinforced h a rd rubbe r.
3 . The rungs ha"e a nonskiJ surface.
4 Run j!s are pace 16 to HI inrlw~ lwt,•·•.•E:: t.he line:; :1cross t•.:rh
rung.
7. Th·· re artance that a pilot should have to climb is 9 meters (30
feet), and an accommoda tion ladder must be used in conjunction with the
ladder as shown in figure 1-13 when !.he dis tance from the water to the
deck exceed'> that amount.
Ue sure to J a~h the accommodation ladder tight alongside' he ship\\ itb
the frapping line U (fig. 1-14). This important li ne is often forgotten, letl '."
ing the accommoda t ion ladder free to swinr{ away from the hull as th(' ,,hip
rolls in a swell at the pilot s tat.wn. Th e frnpping linC' also holds the art·on>
modation ladrlt'r alongside when the sh1p has a smnllltst a nd , s ince the pi·
lot. ladder 1s lashed to the nccommodntion ladde: at pui nt D, this in turn
minimizes the ::!moun t. the long pilot ladder is free to swing.
The acces.; to thr deck must be eit.her through an opening in the bul
wa rk or O\"is t is mwcl, be Rure a conventional ladder is also rig!!ed
alongs1de and available. Many pilots have had enough bad experiences
-.... ilh these ho1st.s that they rMais conteúdos dessa disciplina
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