1143 - Guidelines On Early Assessment Of Hull Damage And Possible Need For Abandonment Of Bulk Carriers

 

Ref. T2-OSS/2.7.1                                                                                                     MSC/Circ.1143

13 December 2004

 

 

1          TheMaritimeSafetyCommittee,atitsseventy-sixthsession(2to13December2002), consideredrecommendationsfordecision-makingemanatingfromvariousformalsafetyassessment (FSA)studiesonbulkcarriersafety.  Inparticular,theCommitteeagreedthatacircularshouldbe preparedaddressingbulkcarrierswhichmaynotwithstandfloodingofanyonecargoholdand containinginformationontheactiontobetakenincaseoffloodingofsuchholds,makingsurethat the professional judgement of the master is not undermined.

 

2          TheCommittee,atitsseventy-ninthsession(1to10December2004),havingconsideredthe recommendationsmadebytheSub-CommitteeonShipDesignandEquipmentatitsforty-sixth session,theSub-CommitteeonSafetyofNavigationatitsforty-ninthandfiftiethsessionsandthe Sub-CommitteeonStandardsofTrainingandWatchkeepingatitsthirty-fifthsession,approved Guidelinesonearlyassessmentofhulldamageandpossibleneedforabandonmentofbulkcarriers, assetoutintheannex.  SomecommoncausesofhulldamagearecontainedintheAppendixtothe annex.

 

3          MemberGovernmentsareinvitedtourgecompanies,asdefinedintheISMCode,that operate  bulk  carriers  flying  their  flag,  to  issue  ship  specific  guidance,  based  on  the  annexed Guidelines,tothemastersofsuchbulkcarrierswithaviewtoimprovingtheprecautionarymeasures andproceduresforemergenciesonboardtheirships.  Thisshipspecificguidanceshouldbebrought

to the attention of all crew members during familiarization training.

 

 

 

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Annex

1          Provoked  by  the  disappearance  and  loss  of  a  number  of  bulk  carriers  from  mid  1970s onwardstheinternationalshippingcommunityhasgrownincreasinglyconcernedthatsuchshipsare particularlyvulnerabletorapidloss.  Consequently,IMOhasbeentakingactionovertheyearsto addressthisproblemandtofindappropriatesolutions.  Amongsuchactions,theOrganizationhas adoptedamendmentstothe1974SOLASConvention,byintroducingchapterXIIin1997(amended in2002),andotherrelatedprovisionsinchapterII-1,andhasalsoamendedtheGuidelinesonthe enhanced   programme   of   inspections   during   surveys   of   bulk   carriers   and   oil   tankers (resolution A.744(18))onseveraloccasions.  Morerecently,anumberofformalsafetyassessment (FSA)studiesonbulkcarriersafetyhavebeencarriedout.  Fromthesestudies,theMaritimeSafety CommitteeofIMOconcludedatitsseventy-sixth sessioninDecember2002thatbulkcarriersdo deservecontinuedspecialattentionandanumberofmeasureswereapprovedtoaddresstheissues identified, both structural and operational.

 

2          Recordsofbulkcarrierlossesindicated,inalargeproportionofthecasesstudied,thatship's mastersoftenappearedtobeunawareoftheimminentdangertheywerein.  Manylosttheirlives togetherwiththeotherseafarerson board as a consequence.  Ship losses were frequently so rapid that the ship did not have time to send a distress signal.

 

3          Therecordsstudiedshowthatintheeventoflossofhullintegrity,inmanycases,bulk carriersshouldbeevacuatedasquicklyaspossible.EARLYASSESSMENTOFTHESITUATION IS  THEREFORE  IMPERATIVE,  COMBINED  WITH  ALERTING  A  MARITIME  RESCUE CO-ORDINATION  CENTRE,  ALERTING  ALL  PERSONNEL  ONBOARD  AND  MAKING PREPARATIONSFOREVACUATION.   Thisisofparticularimportanceforsingleskinbulk carriers which may not be capable of withstanding flooding of any cargo hold.

 

4          Companiesshouldconsiderthefollowingadvicecarefullywithaviewtoimprovingtheir ownprecautionary measuresandproceduresforemergencies.  Theadviceappliesequallytoships other than bulk carriers when carrying dense cargoes.

 

Collision

18       In the event of a collision, masters should call the ships personnel to emergency stations with a strong emphasis on preparing to evacuate the ship. This is particularly important and urgent in cases where a ship is loaded with dense bulk cargo1. Older designs of bulk carriers and small ships with fewer holds are particularly prone to sudden progressive flooding if the damage occurs abaft any strengthened bulkheads in the forward part of the ship. This type of damage is more probable resulting from collisions in dense traffic or overtaking manoeuvres.

 

 

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1         Densecargoshouldbeunderstoodasbulkoresthatdonotcontactsidesorbulkheadsbutshouldalsoincludecertain break-bulkcargoessuchassteelproducts,whichsharesimilarcharacteristics.

Early Assessment

9           When it occurs or is likely to occur, masters should quickly assess damage to their ships by being alert to water ingress and its consequences. The following guidelines are given to assist them in this assessment.

Early Readiness For Evacuation

12    In the event of identifying or even suspecting that the ship may have sustained damage, ships personnel should immediately be called to their emergency stations. A HIGH PRIORITY SHOULD BE PLACED ON PREPARING EQUIPMENT FOR EVACUATION. Abandonment should however only be invoked on the spoken orders of the master following assessment of the risk.

13    Contact with a Maritime Rescue Co-ordination Centre (MRCC) and/or owners should be made early if the master has any suspicion that the ship is damaged. An URGENCY signal is justified and this should be upgraded to DISTRESS if the ship is confirmed as damaged.

Forward Flooding

8         Spaces forward of the collision bulkhead will, in the event of flooding, significantly affect the trim of the ship and reduce freeboard at the bow. In extreme weather this further threatens the ship as green seas come inboard and impact on hatch covers and other fittings that protect the water or weathertight integrity of the ship. Shell plating in the region of the bow protects the fore peak tank and other spaces as do air pipes and ventilators. If any of them are damaged the ships ability to resist further escalation of flooding is compromised.

Heavy Cargoes

5          Inmostcasesinwhichbulkcarriershavebeenlost,heavycargoessuchasironandother denseoresareacommonfactor.Shipsarealsovulnerablewhencarryingcertainbreak-bulkcargoes suchassteelproducts.  Thiscouldincludeothershiptypes.  Thesmallvolumetakenupbythecargo intheships'holdsresultsinalargeunoccupiedspace.Thisprovidespotentialinafloodingscenario forlargevolumesofwatertorapidlydestroytheship'sresidualbuoyancyand,inthecaseofsmaller vessels,itsstability.  Largervesselsarealsohighlysusceptibletostructuralfailureduetoincreases

of weights caused by the influx of water.

 

6          Heavycargoesplacehighloadsonthestructure,andstructuralfailureisthereforemore probable when subjected to the additional forces associated with flooding.

Investigation

15      Masters may wish to investigate any suspected water ingress more closely but preparations for evacuating the ship should be made WITHOUT DELAY and concurrent with any investigation. Remote methods of observation are preferable to sending personnel onto decks, particularly in bad weather and/or at night. Deck floodlights should be used if necessary to try and identify abnormalities. Detrimental effects on watchkeepersí night vision are of secondary importance in such circumstances.

16       In circumstances deemed justifiable for sending personnel onto decks that may be frequently awash with green water, at least two personnel should go to investigate. They should wear harnesses that attach them to a lifeline and to each other and should be in constant (radio) communication with the bridge. Each harness should be provided with two easily operated clips so that wearers are always attached to the ships structure, even when passing across from one lifeline or structural attachment to another. Lifelines on both sides of the deck should be rigged at all times and progress along the deck should always be via the lee or sheltered side. When weather conditions deteriorate is not the time to begin rigging such measures. Fencing or shipside rails alone should not be relied upon without attachment by harness.

17        When a loss of hull integrity is known or suspected, personnel should not be sent onto decks that are being regularly submerged or deeply awash. In such circumstances the ship should be regarded as in imminent danger and priority should be given to preparations for evacuation.

Methods Of Detection

-    Hatch  covers  may  be  dislodged  by  pressure  and/or  sloshing  from  within  a  hold  if flooding occurs through side shell or bulkhead.

 

 

               -    Suddenpressurizationofcompartmentsadjoiningthosethataredamagedorfloodedwill indicate failure of internal subdivision, most notably bulkheads.

 

-    Spacesmaybemonitored,eitherusinggaugingorbilge/waterlevelalarms.  Forward storespacescanalsobemonitoredaudiblyusing “talkback”telephonesthatmaybefitted in  forward  spaces.     Anchor  impacts  and  water  in  the  space  can  be  detected  using telephones of the type that remain active until switched off fromthe bridge.

 

-    HullStressMonitors,wherefitted,maybeabletodetectunexpectedlongitudinalhull girderbending.   Torsionalstressesmayalsobedetectedthroughdifferentialchanges between port and starboard strain gauges.

 

-    Visual  monitoring  from  the  bridge  using  binoculars,  where  fitted,  by  closed  circuit television,cangiveindicationofabnormalwaterondeckandlocaldamage.  However, assessment of trimor freeboard using this method is difficult.

 

-    Assessmentoftrimchangescanincertainconditionsbedetectedbynotingthelevelof the horizon, when visible, against a known reference point on the foremast.

 

-    Draught  and  trim  can  be  assessed  using  draught  gauges.   Changes  are  much  more discernible using this method than by visual means fromabove decks.

Safety And Survival

19        Inthecircumstanceshighlightedabove,particularemphasishasbeenplacedonbeingready forearlyevacuationorabandonmentofthevessel.  Forshipscarryinghigh-densitycargoesthisisof importancewhiletheyareatsea.  Theremayhoweverbecaseswhereabandonmentmaybethe worstoptionandforbulkcarriersaswithothershiptypesthisismostprobablytrueintheeventof grounding.  Incloseproximitytoshore,andespeciallyinbadweather,life-savingcraftlaunched fromtheshipareunlikelytosavetheoccupantsfromtheperilsoftheshorelineandtheprocessof launchingthecraftprobablycarriesmuchgreaterdangerthanremainingonboard.  Again,early contactwithaMaritimeRescueCo-ordinationCentreisimportantandthemastershouldnothesitate tobroadcastanUrgencyorDistressmessage.  Whenagroundandalthoughtheshipmaybeseverely damagedorbrokenintwo,theaccommodationblocksinsuchstrandingsusuallysurvivelong enough  for  helicopter  evacuation,  as  organized  and  co-ordinated  by  the  Maritime  Rescue

Co-ordination Centre, when weather conditions abate.

 

20        Companiesareremindedthatthemasteristheonewhodecidesonwhetherornottheshipis tobeabandoned.  Thisguidanceisprovidedtoassistthemasterinmakingthatdecisionandisbased on the overriding principle that human life is more important than property.

 

21        Companiesarealsoremindedthatemergencycontingencyplanningformsanintegralpartof theInternationalSafetyManagementCoderequiredbySOLASchapterIX.  Theyshouldtherefore assesstheactualrisktotheirshipswithconsiderationoftheinformationgivenintheseGuidelines andprovideintheirSafetyManagementSystemappropriateadvicetoassistthemasterinassessing the action to take in a situation involving flooding of the ship.

Structure

7          Deterioration of structure through corrosion, fatigue and damage is identified as a principal factor in the loss of many bulk carriers. Failing to identify such deterioration may lead to sudden and unexpected failure. Bulk carrier crews may be unaware of the vulnerability of these vessel types. The consequential loss of a ship carrying heavy cargo can be expected to be very rapid, should a major failure occur.

Training

14       Masters should place a strong emphasis on evacuation training so that donning of protective suits and lifejackets, launching of survival craft, and operation of EPIRBs and SARTs is a familiar process to all ships personnel. Also included should be shutdown procedures for main and auxiliary machinery, which can, if left running, hinder launching of survival craft.

Unusual Motion Or Attitude

10        Ifashiptakesonanunusualtrimorheel,orifhermotionsbecomechanged,breachofthe hull envelope should be suspected immediately:

 

-    Unusual collections of water on decks may be indicating trimor heel abnormality.

 

-    Suddenchangesofheelortrimwillindicatefloodingorinsmallershipswithlighter cargoes it may indicate cargo shift.

 

-    Jerky lateral motions can be indicative of largescalesloshingaswouldbethecaseifa hold were flooded.

 

-    Onsmallerships,slowingoftheship'srollperiodmayindicateexcessivewaterwithin thehull-aseriousthreattostability.  ShipsfittedwithGMmetersshouldbeableto identify any unexpected changes in GM.

 

-    Increases  of  water  boarding  forward  decks  may  indicate  flooding  of  a  forward compartment.  Trimandfreeboardchangesarenotoriouslydifficulttoassessfroman after bridge.

Appendix

Causes of damage and failure

 

1          Damagetosideshell,externallythroughcontactwithdocksidesortugsand,internallyfrom impactbycargodislodgingequipmentduringdischarge,canresultininitiatingfracturesand/or fatigue  of  the  structure.   In  single  side-skin  bulk  carriers,  bulkheads,  trunks  and  ballast  tank boundaries,canpresent “hardspots”thatconcentrateforceswherethechangeinconstructionoccurs (e.g. longitudinal to transverse framing).  This may lead to undetected fractures.

 

2          Internaldegradationthroughcorrosionmaybeacceleratedthroughchemicalactionfrom certaincargoes.  Weldsinparticularmaybesubjectto “grooving”corrosion,inwhichthematerial formingtheweldcorrodesatafasterratethantheplatingtowhichitisattached.Fatiguefailuremay result due to loss ofcross-sectional area in the plating joints.

 

3          Inballastholds,sloshingforcesduetopartiallyfilledspaces(suchasmayoccurwhen changingballastforenvironmentalreasons)mayresultindamagetothestructure.Thisdamagemay gounnoticedifitisininaccessiblepositions.  Sloshingisalsoaknowncauseofsecondarydamage after a space has become flooded.

 

4          Damagetobowplatingsuchasispossiblethroughimpactsassociatedwithswingingor looselystowedanchorsmaycauseaninitiatingfractureorfatigueinbowshellplatingthatcould leadtofailureandsubsequentflooding.  Internalintegrityofforwardspaces(thatareusuallyused forballastand/orstores)isthereforeofvitalimportance.   Corrosiondegradationwillseriously reducetheabilityofplatingandstiffeningtowithstandtheforcestowhichitwillbesubjected.  In largerships,partiallyfilledforepeaktanksmaysetupdestructivesloshingforcesunlessthetank structure is designed for this.

 

5          Externalforcesñhorizontaland/orvertical-maycausehatchcoverdislodgement.Thecargo hatchway,ifitlosesitsprotectioninthisway,isamajoraccessforwateringressandaseriousthreat

to the integrity ofthe hull.

 

• Informatietype: Internationaal
• Documentsoort: Circulaire niet in wetten.nl
• Toegangsrechten: Extern
• Identificatie: PUC_1898_14
• Versie: 1
• Datum beschikbaarheid: 07-11-2007
• Geldigheid van: 13-12-2004
• Wijzigingsdatum: 24-11-2016
• Titel: 1143 - Guidelines On Early Assessment Of Hull Damage And Possible Need For Abandonment Of Bulk Carriers
• Organisatie: International Maritime Organization (IMO)
• Taal: Nederlands
• Thema: 1100 until 1199