Ch 4 Ocean Routing- Nadeem Book

7/25/2019 Ch 4 Ocean Routing- Nadeem Book

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Chapter 4 OCEAN ROUTEING

OCEAN ROUTEING

Ocean routeing is part of passage planning, but since it is more complex, itemans special consieration! "or an ocean passage, the entireexpanse of the ocean la#s in front of the mariner! There are climatic$eather patterns an then there are a# to a# changes to the $eather!There is existence of ocean currents an $in ri%en currents,na%igational ha&ars an there is the istance! All these ' an ineenumber of other ' factors nee to be consiere to select a route for anocean passage!

4.1 USE OF CHARTS AND PUBLICATIONS

(ince the climatic patterns an ocean current circulation is uniform most of the

time, the general recommenations can be mae use of for ocean routeing! Anumber of charts, publications an associate material can be use specificall#for the ocean route!

4.2.1. OCEAN PASSAGES FOR THE WORLD

It is publishe b# the U)*O an it contains information on planning oceanpassages, oceanograph# an currents! It pro%ies recommene routes anistances bet$een principal ports of the $orl! These are sho$n as iagramsan chartlets for main ocean routes for po$er %essels an sailing ships! +o$er%essels are i%ie into t$o categories

"ull po$ere Able to maintain a sea-going spee abo%e ./ 0nots!1o$ po$ere *a%ing a sea-going spee of not more than ./ 0nots ue to

po$er, or ue to to$ing or amage!

Generall# the routes are for po$er %essels of a moerate raught! A %alue of.2m is use as moerate raught! The routes for lo$-po$ere %essels are alsosho$n $here appropriate! Routes for sailing %essels shoul also be referre to$hen consiering routes for lo$ po$ere %essels!

Routes are allocate reference numbers an are base upon principal portsan selecte $a#points! The istances are also pro%ie $ithin reasonableaccurac#! 3etails of $ins, $eather, currents, ice an other ha&ars that ma# beencountere are inclue some of this information is in chart format!

There are areas $here routes are ifferent on the eastboun an $estbounirections! (imilarl# there are ifferent choices a%ailable for routes in the sameirection bet$een same ports or $a#points!

In "igure 4!., a chartlet 53iagram 6!.7/ on page .829 from Ocean +assages ofthe :orl has been reprouce! The 3iagram 6!.7/ sho$s the eastboun

routes as 6!.7/ an 6!.76 an number of eri%ati%es of these routes, e!g!,

Na%igation 5A%ance9 for ;ates < ;asters Naeem An$ar 1


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6!.7/!., 6!.7/!.5a9, 6!.7/!.5b9! (imilarl#, 6!.7= an its %ariations are the$estboun routes bet$een same ports!



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The routes bet$een Cape To$nan ports on the :est an(outh coast of Australia an thereasons for the choices are

6!.7/!. Going across Agulhascurrent an ta0ing a%antage ofthe east-going (outhern Oceancurrent an $esterl# $ins, #et0eeping %essel out of theinfluence of the extreme $ins(outh of 47>(! It $ill be (ummer?one from .6 Oct to ./ Apr,other$ise it is mainl# through:inter ?one! Example 8!./ inChapter 8 $as base on this

route, but $ith change ?one!

6!.7/!2 Going across Agulhascurrent, this is the shortest routebut ta0es %essel to boisterous$ins to the (outh! The routeta0es a%antage of east-going(outhern Ocean current an$esterl# $ins!

6!.7/!8 The longest route of allin 6!.7/ range! Initiall# againstthe Agulhas current an thennot ta0ing goo a%antage ofthe east-going (outhern Oceancurrent an $esterl# $ins! @utthe (trong $ins anassociate hea%# seas of the(outhern Ocean are a%oie! Itis $ithin the (ummer ?oneregarless of time of the #ear!

6!.7=A long :estboun route thata%ois the east-going (outhernOcean current an $esterl#$ins, #et 0eeping %essel out ofthe influence of the extreme$ins an associate hea%#seas, an 0eeps $ell $ithin(ummer 1oa 1ine ?one! "orCape To$n, it ta0es full

a%antage of the Agulhascurrent $hen on the coast!


"igure 4!.! Chartlet from Ocean +assages of the:orl 53iagram 6!.7/ at p!.829


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4.1.2 CHARTS

4!.!2!. ROUTEING C*ART(These are pro%ie b# @A for / areas co%ering the oceans of the $orl! (omeother *#rographic ser%ices pro%ie o$n ocean routeing charts!

A chart is pro%ie for each month of the #ear for each of the areas! The title ofchart, bounaries an inset plans inicate the area of co%erage! 3ate ofpublication is at the bottom an last small correction ate an information is atthe bottom left outsie the margin! A 0e# of s#mbols an the instructions arepro%ie on the chart!

There are a number of inset $ino$s pro%iing information 5in pairs as follo$s9 +ercentage freuenc# of $in @eaufort force = an higher enclose b#

green contours an some selecte TR( trac0s for the month in past#ears inicate b# re arro$s!

1o$ %isibilit# percentage freuenc# of less than / nm in green contoursan "og percentage freuenc# of %isibilit# less than 7!/ nm in recontours!

;ean air temperature >" in green contours an ;ean air pressure mb in

re contours! ;ean sea temperature >" in green contours an 3e$ point temperature

>" in re contours!

(hipping routes an istances are inicate as soli lines $ith arro$s pointingin the irection of route! A single arro$ inicates the route shoul be use one

$a# TO, an arro$s in both irections inicate it can be sue in both irectionsTO an "RO;! A straight line inicates a rhumb line route an a cur%e lineinicates a great circle route! 3istances are state bet$een ports or $a#points!

1oa 1ine &one bounaries are sho$n $ith effecti%e ates

parallels of latitue an meriian %alues

latitue an longitue %alues at the change in bounar# irection

?ones are colour coe BTropical-Green B(ummer-+in0 B:inter-@lue

3ate line information is pro%ie on +acific Ocean charts onl#!

Ocean currents are sho$n as green arro$s in the irection of preominantocean currents! The rates are state at the tail of the arro$! D inicates thatthe rate is o%er half a 0not but less than . 0not! F inicates the rate is lessthan half a 0not!

C o n s t a n c # f i g u r e s m a # b e s h o $ n i ff e r e n t l # o n c h a r t s

o rO % e r 6 = = / - . 7 7

8 8 - 6 6

U n e r 8 8

/ . - = 4

2 / - / 7

I n s u f f i c i e n t o b s e r % a t i o n s

o r

o r

" i g u r e 4 ! 2 ! + r e o m i n a n t c u r r e n t a r r o $ s o n r o u t e i n g c h a r t s



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Extreme iceberg limits an ;aximum pac0 ice limits are sho$n in re!

E x t r e m e l i m i t s o f Ic e b e r g s

; a x i m u m l i m i t s o f + a c 0 I c e

" i g u r e 4 ! 8 ! I c e b e r g a n + a c 0 I c e l i m i t s o n r o u t e i n g c h a r t s

:in information is in re an is presente in roses generall# at /> of latituean longitue, $ith more on some coastal regions! The freuenc# is sho$n on ascale on the charts an is 2 inches to .77! It is inicate b# length of thearro$! "rom arro$ hea to the circle the freuenc# is /!

The irection of $in is inicate b# irection of the arro$ Arro$s fl# $ith the$in! The thic0ness an st#le of the arro$ inicates the force of the $in!

. 6 =6

8

. - 8

4

/ - 6

=

H - . 2

" i g u r e 4 ! 4 ! : i n r o s e $ i t h $ i n f o r c e a r r o $

N u m b e r s i n t h e c i r c le

T o p f ig u r e N u m b e r o f o b s e r % a t io n s

; i l e f ig u r e + e r c e n t a g e f r e A u e n c # o f % a r i a b l e $ i n s

1 o $ e r f i g u r e N u m b e r o f o b s e r % e c a l m s

4!.!2!2 GNO;ONIC C*ART(Great circle trac0s appear as straight lines on gnomonic charts! These areuseful for plotting great circle routes in orer to etermine the maximum latitueto be reache an the proximit# to ha&ars! Composite great circle routes canalso be plotte to obtain a general iea about the longitues $here the trac0Joins an lea%es the limiting latitue! In both the cases $a#points can be

selecte for transfer to ;ercator charts!

4!.!2!8 OCEAN C*ART(These are the 4777 series charts co%ering the oceans areas! Catalogue ofAmiralt# Charts an +ublications can be use to select the appropriate oceancharts! The charts ma# not contain e%er# ha&ar an are base upon limiteinformation! The 0no$n ha&ars, li0e islans an roc0s are inclue! It is %er#important to scan the chart carefull# before plotting course on ocean charts!

It is %er# important to plot courses on the charts $hen crossing the oceans as itallo$s the chart to be scanne for ha&ars! It is poor practice to steer onl# to

G+( $a#point $ithout ha%ing a course on an ocean chart!

(imilarl#, the use of ;ercator plotting sheets shoul onl# be limite tona%igation relate plots an not for plotting positions or courses simpl# to ha%ea larger scale in an ocean area $here a small chart is the largest scale chart!

4!.!2!4 1OA3 1INE ?ONE C*ARTThese pro%ie the limits of International 1oa 1ine ?ones! :here use inconJunction $ith gnomonic an ocean charts, it allo$s to plan a legal passagecompl#ing $ith loa line &ones! The ates of seasonal &ones must be chec0ecarefull#! A cop# of the loa line &one chart is inclue in the Ocean +assagesof the :orl an bounaries are sho$n on routeing charts as $ell!



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4!.!2!/ CURRENT C*ART(

4.1.2.5.1 VECTOR MEAN CURRENT CHARTThe mean %ectors inicate the o%erall mo%ement of $ater at the point ofobser%ation, $hich is at mi-length of the %ector! The arro$ represents the long

term isplacement of $ater inicate b# irection an thic0ness of the arro$!The %ector mean current is the resultant of all components of obser%ationsconsiere for a gi%en area! The components are ifferences of north ansouth, an east an $est mo%ements!

N

E

(

:

Resu

ltant

Kec

tor

forire

ction R a t e i s e t e r m i n e b # t a 0 i n g m e a n

o f N < ( a n E < : i s p l a c e m e n t

" i g u r e 4 ! / ! R e s u l t a n t i r e c t i o n

The charts are use to inicate general circulation! Aitionall# Use to fin a%erage rift of obJects o%er a long perio of time

3rifting ships or other erelicts

(ur%i%al craft for search an rescue purposes

Iceberg mo%ement

Use to fin the o%erall mo%ement of $ater o%er a perio, e!g!, spee of

current in miles per a#!

. - /

6 - . 2

. 8 - 2 4

2 / - 8 6

8 = L

.4

6=

" i g u r e 4 ! 6 ! K e c t o r ; e a n C u r r e n t

E x a m p l e

U p p e r f i g u r e i s t h e s t r e n g t h 5 n a u t i c a l m i l e s p e r a # 9

1 o $ e r f ig u r e i s t h en u m b e r o f o b s e r % a t io n s

C e n t r e o f a r r o $ i s t h e m e a n p o s i t i o n o f o b s e r % a t io n

4.1.2.5.2 PREDOMINANT CURRENT CHARTThis is the format use to inicate currents on ocean routeing charts! Arro$points in the appropriate irection an the main bo# of arro$ inicates thechange in irection in that localit#! The rate ma# sometimes be inicate at thetail as a $hole figure or a fraction!

The constanc# is represente b# thic0ness of the arro$! The constanc# isconsiere high $hen a large percentage 5o%er =/ or 6=9 of obser%ationsconfirme $ater mo%ement in the irection inicate! A lo$ constanc# inicates%ariabilit# in rate an irection $here a small percentage 5less than /7 or

889 of obser%ations confirme $ater mo%ement in the irection inicate!



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C o n s t a n c # f i g u r e s m a # b es h o $ n i f f e r e n t l # o n c h a r t s

o rO % e r 6 = = / - . 7 7

8 8 - 6 6

U n e r 8 8

/ . - = 4

2 / - / 7

I n s u f f i c i e n t o b s e r % a t io n s

o r

o r

" i g u r e 4 ! = ! + r e o m i n a n t c u r r e n t a r r o $ s

2

The preominant irection is establishe b# examining the number of occasionsthe current sets $ithin a M7> sector of compass, sa# bet$een north to east! Thesector is rotate b# ./> so that ata of a total of 24 sectors is a%ailable!

The sector $ith the maximum number of obser%ations pro%ies the irection ofpreominant current!

It inicates the current $hich is most li0el# to be experience at a point of

interest an is therefore of the most use to na%igators! Use for passage planning


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4.2 CHOICE OF ROUTES

(afet# is the most important consieration in routeing! In aition to safet#,there $oul be a number of other factors that nee to be consiere inparticular the economic an commercial constraints! The ship an her cargo are

expensi%e propert#! In aition to poor insurance claim recor, liabilit# claimsma# also arise $here ini%iuals or en%ironment are affecte!

4.2.1 OPERATOR CONSIDERATIONS

The compan# concerns can be summarise as A goo $eather route can help a%oi $ear an tear an ensure vessel

safety! 3amage to ship an cargo $ill also be pre%ente! ;aintenancecosts an insurance claims $ill be minimal!

:here engines run at optimum cost effecti%e spee, a route that can

minimise fuel consumption $oul be e!"!#$al! +assenger !#f!%t is paramount, $hich is onl# possible if hea%#

$eather can be a%oie on a route! A ship can onl# procee to ice areas $here st%e"&t'an lass$f$at$!"

allo$ it! 3ue to competition, the o$ners $ant to spen least time on passage

$hich reuires the s(ee) !f (assa&eto be uic0est! The reputation of o$ners or operators ma# be at sta0e if an $"$)e"t

attracts a%erse publicit#!

4!2!.!. T*E CO;;ERCIA1 UE(TION(

The commercial managers $or0 at a number of parameters The compan# polic# on routeing The basis of instructions to ship!

"reight against fuel an running costs . The passage of ship through

ifferent loa line &ones *o$ much more cargo can be lifte if %esselnees to follo$ a longer passage to 0eep $ithin a esire &one

"reight against fuel an running costs 2 *o$ much extra fuel is going to

be consume on a longer fair $eather route to achie%e comfort Charter part# Can the ship procee at agree spee as per charter part#

an can the ship reach port $ithin 1a#time Cancellation 51APCAN9 Expert a%ice :hat are costs an benefits of shore routeing

3amage or 3ela# Is the cost of insurance claims or repair bill on a leasttime route to be more than the claims for ela# on a fair $eather route!

4.2.2 *ASTER+S CONSIDERATIONS

;aster can select from a choice of ocean routes! The routes ma# be baseupon constant or %ariable factors!

4!2!2!. CON(TANT "ACTOR( 3isplacement of the ship

3raught of the ship

Engine po$er of the ship +orts to be calle



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1east epth


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cur%es! A 0no$legeable ;aster shoul ha%e no problem ta0ing routeingecisions on boar, pro%ie the information $as obtaine on a regular basis!



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4.2., SHORE BASED ROUTEING

Recent e%elopments in use of $eather satellites, establishment of extensi%eatabases on oceanographic an meteorological conitions, $eather an $a%emoelling on computers an an extensi%e 0no$lege of shipQs beha%iour in

ifferent circumstances an better communications allo$ the forecasters anrouteing experts to be able to pro%ie routeing a%ice to ships! These ser%icesare pro%ie b# a number of go%ernment agencies an pri%ate establishments!;ETROURE ser%ice of U) is pro%ie onl# on special reuest!

4!2!8!. TP+E( O" ROUTE(These form the basis of aime le%el of ser%ice pro%ie b# the routeing ser%ice

C'"%a" %,ee* is often a charter part# reuirement an if not

maintaine, coul incur a financial penalt#! Lea% &+eis use to 0eep the passage time minimum an is a preferre

choice for large ships carr#ing liui bul0 cargoes or large parcels or r#bul0 cargoes! (uch routes ma# incorporate a fuel sa%ing option!

Lea% *a+a(eis preferre for %essels that carr# cargo $hich is liable to

amage ue to mo%ement of %essel in hea%# sea, e!g!, Ro-Ro shipscarr#ing expensi%e cars!

Lea% &+e a"* #ea% *a+a(eis intene for 0eeping both amage an

financial claims lo$ an is preferre b# most users of the shore baserouteing

(ome %essels ma# ha%e special reuirements Dee, aerroute

Ice freeroute

A## ea!erroute 5e!g!, passenger ships9

4!2!8!2 CON(I3ERATION( "OR A3KICEThe consierations of a routing ser%ice $hen a%ising the %essels are

(afet# of %essel, passengers, cre$ an cargo!

The angers from ice, fog an storms!

(pee an past performance of the %essel!

Classification of %essel!

Compan# an chartererQs preferences!

;asterQs experience an preference! +resent $eather!

"orecast $eather for time of the %o#age!

+roximit# to ha&ars!

Enurance an bun0er capacit#!

Economics of cargo an operations!

+rognosis charts of $a%e heights!

Recommenations from Ocean +assages for the :orl an routeing

charts!

4!2!8!8 ROUTEING +ROCE3URE



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The ser%ice ma# be contracte for a single %o#age, perio of time charter, for aship throughout or for the entire fleet! The contract $oul be mae b# compan#an ma# be mae b# the ;aster!4.2.3.3.1 ON CONTRACTOnce a %essel contracts for ser%ice, the routeing ser%ice reuires some basic

information for entering into their atabase! The ser%ice has to be a%ise ofcompan#Qs preferences an pro%ie $ith the %esselQs particulars anperformance uner ifferent conitions, i!e!, the spee of the ship at ifferentraught


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Course an spee 5ail# a%erage an present spee9

A%erage an +resent meteorological conitions 5pressure, $in, s$ell9

ETA base on present < preicte a%erage spee

4.2.3.3.3 ROUTEIN ADVICE +rior to sailing the pro%isional route $ill be sent to the ship!

At the time of sailing, $hen the ;aster a%ises the routeing ser%ice of the

time of eparture, the route is confirme, or upate if reuire! :eatherreports are also sent to ship an upate e%er# 4H hours!

The %essel upates its position e%er# 24 hours or earlier if reuire,

informing the routeing ser%ice, an routeing a%ice is recei%e e%er# 4Hhours or earlier $hen necessar#!

4!2!8!4 KOPAGE A((E((;ENT(hore $eather routeing is base on information regaring the ship an actual$eather as $ell as forecast $eather conitions! A significant feature of a

routeing ser%ice is the Ko#age Assessment Information pro%ie to the %esselor o$ners after completion of the %o#age!

Pre#&+&"ar$ V'$a(e A"a#$%&%This is a escripti%e account of the route, explaining the reasons for the choiceof the a%ise route, along $ith a summar# of rele%ant $eather conitions! Itgi%es a comparison bet$een estimate a%erage spee an performance speeof the %essel using irect routeing!

V'$a(e A%racIt notes the %esselQs noon positions along the route the $eather experience

an pro%ies estimates of ho$ $eather an currents ha%e affecte the %esselQsprogress!

R'ue&"( C!arThis is a plot of the %esselQs noon positions an the $eather experience!

H&"*ca% C!ar%These are pro%ie on reuest an compare $eather an progress along thea%ise route $ith that li0el# to ha%e been experience along an appropriatealternati%e route! The comparison sho$s ho$ much time the ship ma# ha%esa%e b# follo$ing the a%ise route!

V'$a(e A"a#$%&%This can be pro%ie on reuest for an# %o#age, $hether or not it has beenroute b# the ser%ice! It is esigne to be use speciall# for bun0er or speeclaims! It is uite similar to a %o#age abstract!

R'ue&"( Su++ar&e%This is a seasonal summar# of routes follo$e b# a clientQs %essel5s9! It isprouce on reuest! It assists in assessing the benefits of using the ser%ice!

4!2!8!/ 1EA(T TI;E TRAC)One of the essential elements of an# routeing is the e%elopment of 1EA(TTI;E TRAC)! :ith experience an a%ailabilit# of information onboar, it can



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be prouce b# the na%igator! The information reuire b# the na%igator forconstructing a least time trac0 is the shipQs performance cur%es $ith ifferentrelati%e $a%e irections an ho$ the $a%es an s$ell $ill affect spee $ithchange in $a%e height! A $a%e prognosis chart is also reuire!

1east time trac0 can be built follo$ing the guiance belo$

3 e p a r t u r e+ o s i t i o n

3 e s t i n a t io n

.2

hrs

24

hrs

86

hrs

4H

hrs

" i g u r e 4 ! . 7 ! C o n s t r u c t io n o f T I ; E " R O N T ( f o r 1 e a s t T im e T r a c 0

"rom the eparture position, se%eral trac0s to$ars the general irection

of estination are generate at approximatel# ./inter%als!

The trac0s are ra$n on a transparent o%erla# an are place o%er a

prognosis chart to anal#se the conitions $hich $ill be encountere b#the %essel uring the %o#age on the abo%e trac0s!

After stu#ing the prognostic $a%e height charts, an the %esselQs

performance cur%es, the estimate .2 hour run istance on each of the

trac0s is plotte! These positions are Joine together to form a line 0no$n as ST*E TI;E

"RONT! Ob%iousl# ba trac0s are iscare!

"rom each of se%eral positions on the time front, trac0s are ra$n at ./>

inter%als an the estimate .2 hour run is again plotte! This proceure is repeate t$ice more at inter%als of .2 hours! This

enables a 4H hours contour to be ra$n up! The position on the 4H hours contour $hich is nearest to the %esselQs

estination is the point that the master is a%ise to route b#!

After .2 hours the shipQs actual position is mar0e on the chart, an theexercise is repeate!

:hen estimating istance an spee on the proJecte trac0s, allo$ance

is mae for fog, ice, storms, $ins, currents, $a%e heights an s$ell another na%igational ha&ars expecte to be encountere in accorance$ith the forecast!

4!2!8!6 A3KANTAGE(Routeing a%ice from shore is base on strategic ecisions b# $ell experienceprofessionals $ho ha%e at their isposal extensi%e atabases of oceanographican meteorological information $here as shipQs ;aster ma# be ta0ing ecisions

on the basis of present $eather an near future prognosis!



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Routeing a%ice can be a%antageous to$ars (afet# as ship 0eeps clear of extreme $eather conitions an probabilit#

of se%er catastrophic amage is reuce Reuction in shipQs hull metal fatigue

Reuction in ship an cargo amage ' fe$er emergenc# repairs

Reuction in machiner# $ear an tear ' extene ship operating life (a%ing in fuel consumption an costs ' lo$er operating costs

(a%ing of time ' lo$er operating costs

@etter scheuling of port operations an routine r# oc0ing as time on

passage is not lost +assenger an cre$ comfort enhancing efficienc# an health of cre$

an 0eeping passengers happ# +ossibilit# of maintenance

Reuction in insurance premiums ue to reuction in claims

Reuction in litigation ue to reuction of claims against ships

4!2!8!= 3I(A3KANTAGE( The routeing a%ice is for guiance onl# an final responsibilit# rests $ith

the ;aster! Therefore the ;aster nees to consier the a%ice carefull#before using it for selecting the %esselQs route!

It is possible that e%en $ith routeing a%ice the %essel is unable to a%oi

the $orst $eather on the strategic route, $hereas better a%erage$eather $oul ha%e been possible on the traitional optimum route!

The a%ice ma# ta0e the %essel to$ars an impossible position, $ith no

possibilit# of better options, as a result of poor strategic planning!

;aster an rest of the brige team ha%e to spen time on extra reportsan communication $ith the routeing ser%ice! In certain parts of the $orl, $here $eather remains fair, it is

unnecessar# expeniture an#$a#!

4., OCEANOGRAPHIC AND CLI*ATIC DATA

It is not necessar# for a na%igator to learn the oceanographic an climatic ataof the entire $orl, but it is important to ha%e the 0no$lege to obtain the ataan appl# it to best a%antage! It is %er# important to 0no$ that conitions being

experience at a gi%en time ma# not be the same as publishe ata! The%ariation ma# be ue to ifferences in $eather conitions from the stateclimatic conitions, seasonal changes an extra or insufficient heating of thelanmasses an the sea!

The na%igator must al$a#s be on the guar to obser%e an# e%iation from thenormal an ta0e correcti%e action in time to pre%ent the ship form staning inanger! (imilarl#, %ariations ma# affect the performance of the %essel an thena%igator shoul again aJust the plan to accommoate the ifferences anminimise $astage!



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In the follo$ing sections, a brief summar# of the general oceanographic anclimatic ata of the mainl# freuente ocean areas is pro%ie as brief textnotes, simple maps an bullet points in tabulate format!

The maps ha%e been pro%ie for the months of anuar# an ul# as these

represent the extreme climatic ata an its effects on the ocean currents! Themaps are approximate onl# an ma# not sho$ all islans or the exactcoastlines!



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7>

6

7>E

.2

7>E

.H7

>

.

27>:

6

7>:

7

>

8

7>N

6

7>N

8

7>(

1

O

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*

IG

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a#sN currents sho$ a seasonal %ariation! @et$een the $estflo$ing North an (outh Euatorial Currents, the Euatorial Counter Currentflo$s East onl# uring ;a# to No%ember!

In northern $inter there is no Euatorial Counter Current an the $atergenerall# emerges $ith an extension of the Guinea Current!

:hen gales ha%e been blo$ing (: to :, a set to$ars the entrance to theEnglish Channel from the $est ma# be expecte at up to . 0nots!

The current at the N: of @a# of @isca# is (E to ( to form part of the +ortugalCurrent! A branch enters the ba# an goes $est along the north coast of (pain!:here the gales ha%e been blo$ing from : to N:, east going sets ma# beexperience on the north coast of (pain!



22/32


4!8!.!2 NORT* AT1ANTIC :EAT*ER

(U;;ER 5;AP - (E+TE;@ER9 :INTER 5NOKE;@ER - ;ARC*9

ITC?

The ITC? remains N of the euator

throughout the #ear!

This is an area of calm an light %ariable$ins, also calle the Euatorial troughan 3olrums!

Kisibilit# is %er# goo except in rain!

ITC?

The ITC? remains N of the euator

throughout the #ear!

This is an area of calm an light %ariable$ins, also calle the Euatorial troughan 3olrums!

Kisibilit# is %er# goo except in rain!

The monsoon uring the summer is the

(: monsoon!

Clou# $eather, hea%# rainfall

3uring April an ;a# se%ere sualls,

%iolent thunerstorms uring summer!

:ins are (:Ql#

The monsoon uring the $inter is the NE

monsoon!

:ins are r# an light NQl# o%er 1iberia

an ;auritania an ( an : in the Gulf ofGuinea

:eather generall# fine, moerate %isibilit#

ue to ha&e

3uring October an No%ember se%ere

sualls, %iolent thunerstorms!

NE TRA3E(

The NE trae $ins exten from the ITC?an up to 87VN!

The normal $in force is 4, but ma#

increase to = or ecrease to 2!

In the NE trae $ins area, fair $eather,

little rain, small amount of clous!

*a&e occurs freuentl#!

Kisibilit# is goo except in rain

NE TRA3E(

The NE trae $ins exten from the ITC?an up to 87VN!

The normal $in force is 4, but ma#

increase to = or ecrease to 2!

In the Gulf of ;exico the phenomenon of

%er# strong or gale force $ins occurcalle the Northers!

In the NE trae $ins area, fair $eather,

little rain, small amount of clous!

*a&e occurs freuentl#!

Kisibilit# is goo except in rain!

KARIA@1E( OR *OR(E 1ATITU3E(

1ight or %ariable $ins area extens fromNE trae $in N limit to 82VN!

The preominant $in is bet$een N an

NE!

*urricanes occur in the : part of the

Atlantic Ocean!

Areas affecte Caribbean (ea, Gulf of

;exico, "loria, @ahamas an @ermua!

The# occur from ;a# to 3ecember!

Greatest freuenc# is from Aug to October!

KARIA@1E( OR *OR(E 1ATITU3E(

1ight or %ariable $ins area extens fromNE trae $in N limit to 2HVN!

The preominant $in is bet$een N an

NE!

*urricanes occur in the : part of the

Atlantic Ocean!

Areas affecte Caribbean (ea, Gulf of

;exico, "loria, @ahamas an @ermua!

The# occur from ;a# to 3ecember!

:E(TER1IE(

Area affecte N part of Atlantic Ocean!

Unsettle $eather as a result of continuous

passage of epression in E to NE irection!

ul# is the uietest month!

In ul# the strongest area remains (: of

Icelan!

The freuenc# of $ins of force = is onl#

about = a#s a month!

O%ercast s0ies, rain or sno$, large clous!

:E(TER1IE(

Area affecte N part of Atlantic Ocean!

Unsettle $eather as a result of continuous

passage of epression in E or NE irection!

There is a high freuenc# of strong $ins( south of Cape *orn to47>( close to south coast of Africa!

4!8!.!4 (OUT* AT1ANTIC :EAT*ER

(U;;ER 5NOKE;@ER - ;ARC*9 :INTER 5;AP - (E+TE;@ER9There is no ITC? an hence no TR(! There is no ITC? an hence no TR(!

(E TRA3E(

The (E trae $ins exten from euator to

87V(!

A%erage $in force is 2 to 8!

(light to moerate s$ell!

(E TRA3E(

The (E trae $ins exten from euator to

27V(!

A%erage $in force is 2 to 8!

KARIA@1E(

( limit of (E traes to 8.V(

(light to moerate s$ell!

KARIA@1E(

( limit of (E traes to 26V(!

:E(TER1IE( OR ROARING "ORTIE( :Ql# $ins preominate ( of 8/V(

There is continuous passage of epressions

from : to E, hence the irection an strengthof the $in %aries!

3epressions mo%e from Cabo e *ornes to (!

Georgia an then along /7V(!

Gales are %er# pre%alent ( of 47V ( from mi

summer on$ars!

:in force = pre%ails = - M a#s a month!

( of 48V( an E of 47V: the freuenc# rises

to about ./ a#s per month!

"og is common in summer an is associate

$ith $ins from $arm latitues! 47V( to /7V( mainl# moerate but often hea%#

s$ell!

/7V( to 67V( hea%# s$ell, strong $ins,

abnormal $a%es 5In the %icinit# of shoal$aters ' Gough Is!9

:E(TER1IE( OR ROARING "ORTIE( :Ql# $ins preominate ( of 8/V(

There is continuous passage of epressions

from : to E, hence the irection an strengthof the $in %aries!

3epressions mo%e from Cabo e *ornes to

(! Georgia an then along /7V(!

Gales are %er# pre%alent ( of 47V ( from mi

summer on$ars!

:in force = pre%ails = - M a#s a month!

( of 48V( an E 47V: the freuenc# rises to

about ./ a#s per month!

In $inter this freuenc# is ( of a line Joining

"al0lan Islans an Cape of Goo *ope! 47V( to /7V( mainl# moerate but often hea%#

s$ell!

/7V( to 67V( hea%# s$ell, strong $ins,

abnormal $a%es 5In the %icinit# of shoal$aters ' Gough Is!9

ICE

The approx mean limits of pac0 ice are

inicate on routeing charts, Climatic chartan U!(! ;arine climatic atlas!

The main shipping routes of the (!

*emisphere are not affecte b# pac0 ice butits presence pre%ents the use of GC trac0bet$een Cape of Goo *ope an Cabo e

*arnos especiall# in $inter 5;ar


24/32


The# ha%e been sighte as far as 8.V( off thecoast of (! America 5Argentina, @ra&il9!

The normal iceberg limits are 8/V(!

The# ha%e been sighte as far as 8.V( off thecoast of (! America 5Argentina, @ra&il9!

The normal iceberg limits are 8/V(!

4!8!.!/ CURRENT( IN T*E NORT* IN3IAN OCEAN 3URING (U;;ER5(: ;ON(OON9

Euatorial et bet$een 2>N to 2>( goes east an appears t$ice uring thetransition perios bet$een the monsoon seasons!

There is a cloc0$ise flo$ on the coastal regions of the Arabian (ea an @a# of@engal to clear the $ater that has been pushe b# the (: monsoon! (omaliCurrent flo$s in a NE irection at high rates a%eraging 8 0nots $ith a maximumof H 0nots! At times the actual (omali Current iffers from its general tren!3uring une, this current usuall# sets up another cloc0$ise flo$ bet$een 2>Nan 6>N an south of (uutra, as it lea%es the coast of Africa! This usuall#

happens in to ul# as $ell! 1ate ul# an August see a change as the (omaliCurrent turns at about .7>N!

General easterl# sets occur in the open $aters of the Arabian (ea an @a# of@engal! 3uring une the Euatorial et grauall# ceases an a $ea0 $esterl#set replaces it! In later parts of (eptember, the next phase of Euatorial et ma#begin to set!

4!8!.!6 CURRENT( IN T*E NORT* IN3IAN OCEAN 3URING :INTER5NE ;ON(OON9

General $esterl# sets occur in the open $aters of the Arabian (ea an @a# of@engal! Euatorial et usuall# continues east up to late 3ecember an isreplace b# a broa $esterl# flo$ in anuar# $hich continues up to ;arch! Thecoastal currents change irection

Anti-cloc0$ise in 3ecember an anuar#

Cloc0$ise in "ebruar# an ;arch! Earl# "ebruar# in @a# of @engal an

en ;arch for Arabian (ea!There is a (: flo$ off the coast of (omalia south of about H>N an to the northit sets NE! The NE flo$ shifts to about 4>N in ;arch!

3uring the northern $inter, North Euatorial Current flo$s $est!

4!8!.!= CURRENT( IN T*E (OUT* IN3IAN OCEAN

The (outh Euatorial Current of the Inian Ocean is running $est $ell south ofthe euator as compare to similar currents in the Atlantic an +acific Oceans!To the north of the (outh Euatorial Current, an east going EuatorialCountercurrent ' to . 0not ' sets uring the NE monsoon season, speciall#the $est parts of the Inian Ocean! This Countercurrent merges into theEuatorial et ' . to 2 0nots ' at the start an en of the NE monsoon!

The (outh Euatorial Current splits t$ice once a small branch flo$s along theeast coast of ;aagascar an then at the African east coast, some $ater



25/32


branches N into the East African Coast Current an the other forms the ((:flo$ in ;o&ambiue Channel as the ;o&ambiue Current! The ((: flo$ on theeast an $est sies of ;aagascar Join to form the Agulhas Current, a%eraging2 to 8 0nots, $ith a maximum of / 0nots! A part of Agulhas Current helps to formthe @enguela Current an a small part turns to flo$ east $ith the (outhern

Ocean Current!

On the $est coast of Australia, uring autumn an $inter, sets off the coast aresouth an turn south east off Cape 1eeu$in! 3uring spring an summer, somecoastal e# an some northerl# flo$ N of 88>( is present! To the $est of..8>E, there is a tenenc# for N to N: set $hich Joins the (outh EuatorialCurrent! :hen this N to N: current is more constant, it is terme the :estAustralian Current!

4!8!.!H IN3IAN OCEAN :EAT*ER

(U;;ER 5;AP - (E+TE;@ER9 5(! $inter9 :INTER 5 NOKE;@ER - ;ARC*9 5(! summer9

NORT* IN3IAN OCEAN (: monsoon pre%ails

+erio une to (eptember

In the Arabian (ea TR( season is

;a#


26/32


Extens from euatorial trough to 87V(

"orce 8 - 4

Extens from euatorial trough to 2=V(!

"orce 4 - /

KARIA@1E(

Extens bet$een ( limit of (E trae $ins an

8/V(

1ight an %ariable $ins

"air $eather

KARIA@1E(

Extens bet$een ( limit of (E trae $ins

an 87V(

1ight an %ariable $ins

"air $eather

:E(TER1IE(

Extens bet$een ( limit of %ariables an N

1imit of +olar easterlies!

:ins are $esterl# an epen on east

mo%ing gales

The centre of most of these epressions pass

( of /7V(!

:in force = is experience for D6 -.2 a#s

per month ( of 47V(!

:eather is %ariable, o%ercast s0ies, rain or

sno$ associate $ith fronts of east mo%ingepressions!

:E(TER1IE(

Extens bet$een ( limit of %ariables an N

1imit of +olar easterlies!

:ins are $esterl# an epen on east

mo%ing gales

The centre of most of these epressions

pass ( of /7V(!

Gales are pre%alent in $inter $here the $in

force = is pre%alent .2-.6 a#s per month!

:eather is %ariable, o%ercast s0ies, rain or

sno$ associate $ith fronts of east mo%ingepressions

ICE

Greatest extent of pac0 ice is from Aug-(ept

an runs from about //V( 777V to /HV( 7/7VE,67V( ..7VE!

The GC routes bet$een (! Africa an Australia

are obstructe!

Icebergs mean limit reaches farthest N

bet$een 27VE an =7VE in No% an 3ec $henit runs from 44V( in the longitue of Cape

Agulhas

ICE

The GC routes bet$een (outh Africa an

Australia are obstructe!

Icebergs mean limit e%er#$here ( of /7V(!

4!8!.!H CURRENT( IN T*E NORT* +ACI"IC OCEAN

North Euatorial Current flo$s $est$ar in the general area of the NE Traes!The (outh Euatorial Current also flo$s $est$ar in the area of (E Traes! Inbet$een the t$o is the $ea0er east going North Euatorial Countercurrent ataroun />N to =>N!

The North Euatorial Current cur%es to$ars +hilippines an Tai$an, $here iteflects further north to become )uroshio 5also calle apan Current9, $hichmo%es NE! Tsushima Current $hich flo$s NE along the $est coast of apan!:ater from )uroshio cur%es east an $iens bet$een Aleutians an the*a$aiian Islans an is 0no$n as the North +acific Current! As North +acific

Current approaches the $est coast of North America, it turns (E to becomeCalifornia Current! 3uring the $inter, 3a%ison Current flo$s northerl# insie ofthe California Current!

Aleutian Current flo$s east an Alas0a Current flo$s northerl# along the coastof Alas0a! )amchat0a Current flo$s (: along the Russian coast to the north ofapan!

4!8!.!M CURRENT( IN T*E (OUT* +ACI"IC

(outhern Ocean Current flo$s easterl# aroun latitue 4/V(! +eru Current flo$s

N to N: an fees into the (outh Euatorial Current, $hich is $est going at theeuator!



27/32


East Australian Current is going ( along the coast! Its section from Australia toNe$ ?ealan is calle Tasman "ront an on the east coast of Ne$ ?ealan, itbecomes East Auc0lan Current!



28/32


4!8!.!.7 NORT* +ACI"IC :EAT*ER

The ITC? remains permanentl# N of euator at 1ongitue E of .67V:!

To the : of .67V: it lies in the (! hemisphere from about No% or 3ec until Apr or ;a#!

In the Northern summer it is %irtuall# non-existent : of ./7VE

NE trae $ins blo$ on the euatorial sie to 87VN!

:in force 8 - 4 but often freshens to / - 6

NE monsoon begins generall# about (eptember in the north an close to euator aroun

(eptember!

In the summer of the N! hemisphere the (: monsoon is present!

"og is pre%alent uring summer!

The fogg# season reaches its maximum in April off *ong )ong, an in the apan (ea fog is about 8

- 4 a#s per month an / -= a#s per month off Northern *onshu!

After ul# the fog incients rop sharpl#!

:in force is 8 - 4 in (outh China (ea an force 8 else$here!

TR( is pre%alent in summer $hen $ins ma# reach force = an abo%e!

These are 0no$n as T#phoons in the :est part an *urricanes in the East part!

The areas affecte b# T#phoon are Caroline Islans, ;ariana Islans, +hilippines, (! China (ea

near the coast of China an Tai$an, China (ea an apan!

TR( acti%it# is bet$een une an October!

(eptember is the month of greatest freuenc# of TR(!

The %isibilit# along the Chinese coast is reuce b# sea fog!

Kariable belt is from 2/VN to 87VN in $inter an 8/V - 47VN in summer!

1ight an moerate $ins are pre%alent!

:ins in summer are generall# light an rarel# reach force = unless associate $ith tropical storm!

At the height of $inter season in anuar#, $in forces reach = or abo%e in the areas N of 47VN!

The $eather consierabl# %aries in the $esterlies uring summer an $inter!

N of 47VN there is a continuous passage of epressions from the %icinit# of China an apan in a

NE irection to$ars the Aluetian Islans an south of Alas0a!

(trong $ins an gales are %er# freuent E of apan, ( of Aluetian an Alas0a peninsula $here the

$in force reaches force = or abo%e more than .2 a#s a month!

Kisibilit# is reuce b# rain an sno$!

In summer epressions are less freuent, much less intense an their trac0s are further North than

in $inter!

+olar easterlies, in $inter since most epressions tra%el (outh of Aluetian Islans, the $ins in the

@erring (ea are mostl# easterl#!

4!8!.!.. (OUT* +ACI"IC OCEAN :EAT*ER

ITC? remains North of Euator throughout the #ear E of .67V:

To the : of .67V: it lies in the (! hemisphere from about No% or 3ec until Apr or ;a#!

:eather is t#pical of ITC? Calm, 1ight %ariable $in an fine $eather alternate $ith sualls,

hea%# rain an thunerstorms!

The %essel $ill be in the (E Trae $ins &one throughout her passage! There is a *igh on 87V(, : off Chile!

The (E trae $in limit is from euator to 27V(!

The irection of trae $ins is south easterl#

The a%erage strength of the trae $ins is about force 4, but often strengthens to about force 6!

:ins of force = or more are unli0el# for more . or 2 a#s per month!

O%er the open oceans $eather is fair $ith occasional sho$ers!

(0ies are about half co%ere $ith small cumulus clous!

There is slight ha&e $hich reuces the %isibilit# to H-./ nm!

Clou# $eather $ith o%ercast s0ies is common $hen approaching coast of (outh America!

"og an mist are rather to$ars the coast of (! America o%er the col $aters of +eru Current

but rarel# occur else$here!

27V-87V( is an area of %ariable $ins!

Tropical storm area is : of .//V: an ( of HV-.7V(!

The storm perio is from 3ecember to April!



29/32


Greatest freuenc# of storms is form anuar# to ;arch! These are not un0no$n at other times!

(outh euatorial current sets :N: ' :(: of moerate to high constanc#!



30/32


4.4 GENERAL HA-ARDS ENROUTE AN OCEAN PASSAGE

The follo$ing is a brief summar# of the li0el# ha&ars to be encountere on anocean passage! The list is not exhausti%e!

(parse h#rographic information, some ha&ars ma# still be uncharte! There ma# be lot of islans in the archipelagic $aters at short istances!

(ome islans ma# be unlit an ma# not be %isible uring ar0ness!

(ome islans ma# be %er# lo$ an ma# not be %isible at reasonable

istances or pic0e up b# raar at safe istances! "ishing craft in %icinit# of coasts an small islans ' some of these craft

ma# not be lit or ma# be improperl# mar0e or lit! 1eisure crafts ma# be present in %icinit# of coast, small islans an at

times e%en in open seas! Cruise ships ma# pass %er# close to islans or coast an ma# emerge

suenl# as the# ma# ha%e been obscure earlier! (ome charts ma# be base on %er# ol sur%e#s!

(ome charts ma# be %er# ol an of an inaeuate scale!

3iscrepanc# bet$een charte an actual positions 5as eri%e from

moern na%igation s#stems or celestial obser%ations9 ma# be %er# large!There is no ata a%ailable for correcting such positions!

Cross currents, especiall# in %icinit# of islans can set %essel to$ars

anger! (ome of these currents ma# be %er# strong! Traffic ma# cause concerns, especiall# crossing $here regular shipping

lanes cross or hea-on in freuent shipping lanes!

"orce of $in ' areas $here gale force or stronger $ins are li0el#! Tropical re%ol%ing storms! Kessels at times on certain heaings ma#

encounter the same TR( t$ice before an after re-cur%ature! 1arge $a%es an hea%# s$ell!

Areas $here abnormal $a%es ma# occur or Tsunamis!

Kisibilit# affecte b# rain, falling sno$, fog, san storms an ha&e!

Clou# conitions or poor %isibilit# ma# not allo$ celestial obser%ations!

Thunerstorms, suen sualls an $ater spouts!

Icebergs an other forms of ice!

Areas of offshore acti%it# an sur%e#!

Absence of aeuate areas for choosing a suitable lanfall position! Arme attac0s, pirac# an arme robber#, an other securit# concerns!

+ossibilit# of ebris falling follo$ing satellite launch!

It must be appreciate that the list is generic onl# an the actual ha&ars on apassage ma# not inclue all items $ithin the list! Note that there is no ice in theCaribbean (ea or other lo$ latitues! (imilarl# there is no TR( or unlit islansin the (outh Atlantic! Other irrele%ant points li0e these shoul not be inclue tolists in passage plans as the inclusion unermines the %alue of input effort!

4.4.1 RECAP OF FACTORS FOR CHOICE OF ROUTES



31/32


The shortest route is not al$a#s the uic0est! The factors to be ta0en intoaccount $hen choosing the route are

3istances b# %arious routes

Recommenations from Ocean +assages of the :orl

1oa 1ine &ones

+roximit# to na%igational ha&ars, poor %isibilit#, such as ice, offshoreacti%it# an hostile acti%it#

A%ailabilit# an consumption of bun0ers, along $ith intermeiate

bun0ering ports +re%ailing $eather conitions, presence of storms or epressions

Climatic conitions incluing general $in circulation an state of the sea

"a%ourable or a%erse currents

T#pe of cargo

A%ice an recommenations b# routeing ser%ices

ChartererQs instructions

Compan# preferences, incluing insurance polic# $arrant# limits Time a%ailable

+osition fixing reliabilit#

3amage li0el# to be sustaine

;aintenance $or0 planne uring the %o#age

Comfort of cre$ an passengers

+oints $here stores an bun0ers are to be replenishe

Amount of traffic li0el# to be encountere

3raught at %arious stages of the %o#age

EAMPLE 4.1 Effec 'f *&%a"ce &"* a"* curre" '" ,a%%a(e &+e.(pee .6 )nots3istance 8.87 8227 84/7(teaming time H 8h 8HmWW H Mh ./m H 28h 8HmCurrent Against 2 0tsWW Against . 0t "a%our 7!/ 0tCurrent time factor L 24h 2=mWW L .2h 8/m - 6h 44m:in effect on spee Against 7!/ 0t Against 7!/ 5/79 Against 7!/ 5./9:in time factor L 6h =m L 8h Mm L .h .mTime on passage M .7h .2m M 7h /Mm H .=h //m

WWTime lost ue to current calculation H 8h 8Hm x 20nots 8M.X!2= Y .6 0nots 24h 2=m

The time on passage gi%es an inication for the optimum choice! In aitionaffects on progress ue to fog an s$ell ma# also affect the progress a%ersel#!The other factors from the abo%e list must be consiere to ecie the route!

CONCLUSION

;oern ship esigns an high costs of construction, expensi%e cargo, e%erincreasing liabilit# pa#ments, increase costs of fuel, costs an time out forrepairs, unnecessar# $aiting times, cut throat competition, heightene meiainterest all put pressure on ;aster an the ship operators to emonstrate a

performance $here error has no room!



32/32


Use of efficient methos of planning a propose transit together $ith a carefulstu# of all the elements, particularl# $eather, before an uring the %o#agepro%ie an opportunit# for the optimum conitions to be use to best a%antagefor the %o#age ensuring safet# an $ithin reasonable operating costs!

Ch 4 Ocean Routing- Nadeem Book

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