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2  Chapter 3  PASSAGE PLANNING  Introduction  Planning may  be considered in n.vo stages:  Ocean  and  open  waters.  Coastal  and estuarial waters.  Though, at times,  these  t:\.vo stages will merge and overlap.  Charts Coll ect together all the charts for the intended voyage, putting  them into the correct order. Charts not absolutely necessary for  the  voyage but which are adj acent to the area to be traversed should be  included,  as  should  very  large  scale  charts,  e.g.  port p
  2 Cha  t r 3 PASSAGE PLANNING Introduction Planning ma y be considered in n vo stages: Ocean and open waters. Coastal and estuarial water s. Though, at times, these t:\ vo stages will merge and overlap. C   rts Co ll ect together all the charts for the intended voyage, putting them into the correct order. Charts not absol ut ely necessary for the voyage but which are a dj ace nt to the area to be traversed should be included, as should very large scale charts, e.g. port plans on the coastal part of the voyage. Although it may n ot be necessary to actually use such charts, they ma y include information that will prove of use during the voyage. Ensure that all charts and pubUca li ons have been cotTected to the latest Notice to Mariners available and that any authentic Nav warnings etc. received fr om any source are also included (see Annex II ). Similar corrections may also ha ve to be made during the voyage a ft er the plan h as been completed and the plan having LOb e subsequently modified. No Go Ar eas Coastal and estuarial charts should be ex amined, and a ll areas where the ship C NNOT go must be care full y sh own by highlighting or cross hatchin g, care being taken to not obliterate information such as a navigation mark or a conspicuous o bj ecl. Areas so marked are to be considered as no- go areas. In waters where the tidal range may not be very large, no-go areas will include a ll c hart ed depths of less than the ship's draug ht plus a safety margi n. Such areas w ill vary according to the ship's draught so w ll not necessarily be the sa me for both inward and out:\.vard passages. In general the line determining no-go w ill be not less than draught 10 , though this will n ee d to be mod ified according to th e pr eva iling circumstances. Draught 10 % may we ll prove adequate in areas where e sea is smooth but will require a c on siderably high er fi gure i the sh ip is li able to pitch, ro ll or squa t. In confmed water s, where the tidal heig ht ma y have a large influe nc e, such no -go areas will vary according to the time of pa ssage. Initially a ll areas and dangers shov.ring ch ar ted depths of less than th e draught pl us the sa fety m arg in should be considered no-go, though such no go areas may be subsequ en tl y . am ended wh en the actual time of passage is known. Such areas will need to be carefully marked showing th e times and stale of tide at which they are safe. Figure 1 shows no go areas f or a s hip on a draught of 9· 1 metres, approximating to the 10 metre co ntour , no allowance be in g made for tidal heig ht 16 THE NAUTICAL INSTITUTE    7 ' ' .. J< I / JJ ,, 1 , ~~ . , ' . . I I / ''ã '' ã C IS tã SI'I ,. o c , rã ã  » ' ' Y ; - ' ' : . _ -- ~  . .   \ ,., .. ro I Sot . 'A' f'i l i 'ã ' ' \ ·   ' .....:  :....,- '-,---,. - -.', -..,- -..,--...,- ... r r ·T - - ..   . · . Jl r- . . . , r· , . n· Figure 1 NO -GO AREAS Assuming ship on maxim um draught 9·  metres Cr own copyri g ht Reproduced from Admiralty Chart 3274 with t permission of the Hy dro grapher of the Nav y BRIDGE TEAM MANAG EM ENT 17   argins afety Safe Water Beforetracksaremarked on thecharttheclearingdistancefromtheno-goareasneedsto be considered.Whena fix is plotted on achartitinvariablyrepresentsthepositionofacertainpartof theship'sbridgeatthetimeofthe fix Withlargeships,althoughtheplotted fix atacertaintimemaybeoutsideano-goarea, it is possiblethatanotherpartoftheshipmayalreadybeinit-withdisastrous results.Asafetymargin is requiredaroundtheno-goareas at adistancethat,intheworstprobablecircumstances,thepartofthe shipbeingnavigated(thebridge)willnotpass. On occasion,themarginsofsafetycanbereadilymonitored by eye,e.g.usingbuoysmarkingthesafelimitsofachanneloreasilyidentifiedclearing bearings.Amongthefactorswhich need to be takenintoaccountwhendecidingonthesize of this MarginofSafety are:1Thedimensionsoftheship. 2Theaccuracyofthenavigationalsystemsto be used.3Tidalstreams.4 The manoeuvringcharacteristics of theship. The MarginsofSafetyshouldbechosensothattheycanbe read il ymonitored. To achievethistheyneedto be related to oneofthenavigationsystemsinuse(e.g.clearingbearingsrelated to aheadmarkorPara ll elIndexes). MarginsofSafetywillshowhowfartheshipcandeviatefrom track,yetstillremaininsafewater(seebelow}.Asageneralrulethe MarginofSafety will ensurethattheshipremains in watersofadepthgreaterthan draught 20%.  t isstressedthatthis is onlyageneralrule.Circumstancesmaydictatethatthe20%clearance will need to beconsiderablyincreased,e. g: 1 Whenthesurveyisoldorunreliable. 2 In situationswheretheship is pitching or rollin g 3 Whenthere is apossibilitythattheshipmay be experiencingsquat.4 When theshipmayhaveincreasedthedraughtbypassingintofreshwater.Areaswheretheship may safelydeviateareconsidered to beSafeWaterandthelimitsofthissafewaterare bounded bytheMargins of Safety. 18 THE NAUTICALINSTITUTE    ã .... . \ ,, \ ' Margin s of Saf et y shown as Clearing Beari ng s of Na vigati ona l Marks ''ã ''ã lSI ,, , ,, ). 11 . . . '· ,. .r ::___ GIJ6o:l 'ã I ' · .. .. ... .. , .. ,   , ..   ,, .,. . ·  - 4 I IIJ <> .r ... \Jã II ' - . ãã ' , - ,-   r · r -   09 Oll ' 01' · ooc - .. \ .. ãã No 'ãn Figure MARGINS OF SAFETY for definition of Clearing B earing s see below) Crown copyright. Reproduced from Admiralty Chart 3274 with th e permission of the H ydrogra ph er of the Navy. BRlDGE TEAM MANAGEMENT 19

Adventure 14

Jul 23, 2017


Jul 23, 2017
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