《轮机英语（二三管轮）》-Lesson 23 Steering Gear

NewWordsandExpressionssteer[stɪə(r)]v.掌舵，驾驶steeringgear

操舵装置，舵机rudder[ˈrʌdə(r)]n.舵，方向舵，操舵duplicate[ˈdjuːplɪkeɪt,ˈdjuːplɪkət]a.完全一样的：复制的impair[ɪmˈpeə(r)]v.损害；削弱helm[helm]n.舵轮，舵机fined[faɪnd]v.处…以罚金detain[dɪˈteɪn]v.拘留；扣押NewWordsandExpressionsbuckle[ˈbʌkl]n.扣，弯扣entrapment[ɪnˈtræpmənt]n.滞留tiller[ˈtɪlə(r)]n.舵柄，翻转装置Apropelleristhedevicethatforcestheshipforwardthroughseawater,butwhatisitthathelpsinchangingaship’scourseordirection?Itcertainlyrequiresquiteabitofefforttoturnaroundahugeshipandtheremustbesomereliableandefficientmechanismtoachievethesame.Arudder,attachedandsuspendedinsuchawaythatitstaysjustbehindthepropeller,isusedtodirectaship.Therudderisinternallyconnectedtoasteeringgear,whichthroughitsmechanism,controlsthemovementoftherudderandthusthatoftheship.Thesteeringsystemofashipprovidesaresponsetothesignalfromthebridgebymovingtherudderinthedesireddirection.Inthisarticlewewilllearnaboutthehydraulicsteeringsystemsusedinmarineapplications.Thesteeringgearsystem(seeFig.23-1)hasthreemainparts:controlequipmentpowerunittransmissiontotherudderstock.Inbrief,theoperationofthesteeringgearcanbeexplainedas-Withthehelpofthecontrolsystem,asignalofdesiredrudderangleissentfromthebridge.Thissignalactivatesthepowerunitwithwhichtherudderisattached.Theruddermoveswiththehelpofthepowerunittilltherightangleisreached.SteeringGearSystemSteeringGearSystemFig.23-1SteeringGearSystemsforShipAllshipsmustbeprovidedwithanefficientmainandauxiliarysteeringgearandexceptforverysmallvessels,themainsteeringgearmustbepoweroperated.TheauxiliarysteeringgearmustalsobepoweroperatedwhentheRulediameteroftherudderstockexceeds230mmforpassengervesselsand250mmforcargovessels,althoughthelowerfigureof230mmislikelytoapplytoallvesselsinafewyearstime.Whilstitisdesirablethatthemainandauxiliarysteeringgearsshouldbeentirelyindependentofeachother,thisisrarelyachievedinpracticesincebothgearscommonlyshareahydraulicactuatorwhichmayormaynotbeduplicated.MainandAuxiliarySteeringGearThemainsteeringgear,withtheshipatherdeepestseagoingdraught,mustbecapableofputtingtherudderoverfromanangleof35°ononesideto35°ontheothersidewiththeshiprunningaheadatmaximumservicespeed,itmustalsobecapableofputtingtherudderoverfrom35°oneithersideto30°ontheothersideinnotmorethan28sec,underthesameconditions.

主操舵装置必须满足能在船舶处于最深航海吃水并以最大营运航速前进时将舵自任何一舷35°转至另一舷的35°，并且于相同的条件自一舷的35°转至另一舷的30°所需的时间不超过28s。MainandAuxiliarySteeringGearTheauxiliarysteeringgearneedonlybecapableofsteeringtheshipatnavigablespeedbutitmustbecapableofbeingbroughtspeedilyintoactioninanemergency.Navigablespeedisgenerallyconsideredasonehalfofthemaximumservicespeedaheador7knots,whicheveristhegreater.辅助操舵装置只需能以可航航速操纵船舶，但必须能在紧急情况下迅速发挥作用。可航航速一般被认为是最大航行速度的一半或7节，两者中以较大者为准。MainandAuxiliarySteeringGearWherethemainsteeringgearcomprisestwoormoreidenticalpowerunits,anauxiliarysteeringgearneednotbefittedinapassengervesselprovidedthatwithoneunitoutofactionthegeariscapableofputtingtherudderoverin28secinthemannerabove.Asimilarrulingappliesforcargovesselsbutwiththelessonerousconditionthatthesteeringgearneedonlymeettheaboverequirementforauxiliarygear,withallpowerunitsoperatingsimultaneously.当船舶配备的主操舵装置具有两台或几台相同的动力设备时，可不设置辅助操舵装置。但是对客船来说，任一台动力设备不工作时，主操舵装置仍能按规定（28s）进行操舵；但对条件没有那么繁杂的货船来说，则在所有动力设备都工作时，主操舵装置能按规定进行操舵。MainandAuxiliarySteeringGearFortheabovetoapply,itisessentialandsofarasisreasonableandpracticable,thatasinglefailureinthemainsteeringgearpowerunitsorpipingwillnotimpairtheintegrityoftheremainingpartofthesteeringgear.Thesteeringgears,bothmainandauxiliary,arerequiredtobeofadequatestrengthfortheirrespectivedutiesasalreadydefined.Themainsteeringgearmustalsobedesignedsoastoensurethatatmaximumasternspeedneitherthegearnortherudderstockwillbedamaged(主、辅操舵装置应该有符合规定的强度。主操舵装置应设计成在船舶以最大倒车速航行时主操舵装置和舵杆不致损坏).MainandAuxiliarySteeringGearRuddersFig.23-2RudderInpassengershipswheretheRulediameteroftherudderstockexceeds230mm,analternativesteeringpositionremotefromthemainpositionistobeprovidedandmustbearrangedsothatfailureofeithersystemcannotrendertheothersysteminoperable(对于舵柄处舵杆直径大于230mm的客船，须设置一个与主操舵位置相对独立的备用操舵位置，而该位置的布置须使任何一个系统的故障不能使另一个系统不能操作).Provisionmustbemadetotransmitordersfromthebridgetothealternativeposition.Theexactpositionoftherudder,ifpoweroperated,mustbeindicatedatthemainsteeringpositionandthemethodofindicationmustbeindependentofthesteeringgearcontrolsystem.RuddersAnefficientlockingorbrakearrangementmustbefittedtoallsteeringgearstoenabletheruddertobemaintainedstationaryifnecessary.Allpoweroperatedgearsmustbefittedwitharrangementsforrelievingshock;thisisarequirementtoprotectagainsttheactionofheavyseasagainsttherudder.Thereliefvalveprovidedwithsomefixeddisplacementpumpsoperatinghydraulicsteeringgears.Suitablestoppingarrangementsaretobeprovidedfortheruddersoastorestrictthetotaltravel.Cutoutsonthesteeringgeararetobearrangedtooperateatasmallerangleofhelmthanthosefortherudder.RuddersSteeringgeartestingcomprisesofaseriesoftestsonthewholesteeringgearsystemthatshouldbecarriedoutreligiously.Thetestsinclude:Testingofthemainsteeringgearoperation.Testingoftheauxiliarysteeringgearsystem.Testingofthemainandstandbypump.Testingofthetele-motorsystem,remotelyoperatedfrombothbridgeandenginecontrolroom.Testingsteeringgearoperationwithemergencypowersupply.Testingofrudderindicationsystemwithrespecttothetrueangleofrudder.Testingofremotecontrolalarmsandsteeringgearpowerunits.Testingofautomaticisolatingarrangements.SteeringGearTestingOilLeakages:Portstatecontrolshaveverystrictpolicyofzeroleakagefromship’ssteeringgear.Manyshipshavebeenfinedanddetainedduetosuchfaultspointedoutduring

portstatecontrolinspection.Still,oilleakagefromthesteeringgearisoneofthemostcommonproblemsonships–aresultofmachinerysystemshavingseveralmovingpartsoperatedbyhydraulicoil.Someofthemain

areasofleakagesarecylinder-ramsealinhydraulicramtypesteeringgearandsealinthechambersofarotaryvanepump.Needlesstosay,anykindofleakagefromsteeringgearsystemmustberectifiedimmediately.CommonProblemsFoundinSteeringGearSystemofShipsAnothercommonproblemobservedinsteeringgearsystemisthedifferenceintheanglegivenatthehelmandtheactualrudderangle.Thisoccursduetowrongorinsufficientadjustmentofcontrolandrepeatbacklever.Torectifythisproblem,theturnbuckleattachedtotherodofcontrolandrepeatbackleveraretobepreciselyadjusted.DifferenceintheActualRudderAngleandOrderedHelmAngle:Thefuelconsumptionoftheshipgreatlydependsontheefficiencyofsteeringgearoperation.Ifthesteeringgearisoperatingunsatisfactory,itwillleadtodelayintheETAoftheshipandincreasemainenginefuelconsumption.Commonreasonforthisproblemismalfunctioningofsafetyvalvesorbypassvalvesinthesystem.Anyprobleminthecontrolandrepeatbackleverwillalsoleadtounsatisfactorysteering.Tosolvethisissue,safetyandbypassvalveoperationaretobecheckedatregularintervals.Ifanyproblemisnoted,sametoberecitedattheearliest.Forcontrolandrepeatbacklever,theturnbuckleattachedtotherodofcontrolandrepeatbackleveraretobepreciselyadjusted.UnsatisfactorySteering:Excessivenoiseandvibrationsfromthesteeringgearindicatesentrapmentofairinthesystem.Duetoairbubblesintheoil,pumpsandpipingsaresubjectedtoairhammerleadingtovibrationandheavynoise.Airmustberemovedfromthesystemusingventvalveprovidedinthecylinderandpumpspeciallyafterthesystemisreplenishedwithnewoil.Ifthevalvelocatedintheoilsupplytankofthesteeringgearisthrottledorclosed,itwillagaindevelopairbubblesinthesystem.Ensurethatthisvalveisalwaysopenwhenthesystemisinoperation.ExcessiveNoisefromSteeringGear:Oilistheoperatingmediainthesteeringgearsystem.Anyabnormalityintheparametersofoilwillleadtootheroperationsrelatedproblemsinthesteeringgear.Ifthereisincreaseintheoiltemperature,itwilldirectlyreducetheviscosityoftheoilandhamperthesteeringoperation.Themostcommoncauseofincreaseinoiltemperatureislowoillevelinthesystem.Thus,ensurethatlowoillevelalarminthetankisworkingandreplenishtheoilwhenrequired.HighOilTemperature:TheSOLASrequirementforsteeringgearsaysthatthesystemmustbecapableofputtingtherudderoverfrom35°ononesideto35°ontheothersideoftheshipatitsdeepestseagoingdraughtandrunningatmaximumaheadservicespeed.Itmaysometimeshappenthatthemaximumanglereachedbytherudderislessthanprescribedortherudderisovershootingthe35°anglemark.Oneofthemainreasonsforthisproblemismalfunctioningoflimitswitchfittedontherepeatbackunitorontheautopilot(造成这一问题的主要原因之一是装在回动装置或自动驾驶仪上的限位开关失灵).Replacethemalfunctionedlimitswitchoradjustthelimitswitchtomaximumprescribedrudderangle.RudderMovementisWithinorBeyondtheLimit:Thereisalwaysaprovisionoflocalmaneuveringinthesteeringgearforemergencysituationiftheremotecontroloperationfails.Somecommonreasonsforfailureofremovecontrolsare:Breakdownofhydraulicpumps:Otherhydraulicpumptobestartedinsuchcases.Malfunctionoftransfervalve.MalfunctioningofhydraulicbypassvalveinthepumpOilleakageProblemintelecontrolsystem.NoSteeringfromRemotecontrol:On29April2011,thePanamaregisteredbulkcarrierDumungroundedwhiledepartingtheportofGladstone,Queensland.Priortothegrounding,theship’ssteeringappearedtohavestoprespondingtobridgecommandswhenthelinkagebetweenthetillerandrudderangletransmitterdetached(在搁浅之前，当舵角发送器与舵柄之间的传动杆件断开时，船舶的舵机装置已经停止了对驾驶台指令的响应).Thesteeringgearcontinuedtooperatenormally,butthetransmitterlostitsinputsignaland,asaresult,thebridgemountedrudderangleindicatorstoppedworking.Suchcasesarerarebuttheydooccur(舵机正常工作，但舵角发送器失去其输入信号，因此安装在驾驶台上的舵角指示器停止工作。这种情况很少见，但确实发生过).Toavoidsuchaccidents,ensurethatthedutyofficermusttakearoundbeforeeverymaneuveringordepartureporttocheckallthelinkagesintheengineroom.RudderAngleTransmitterandTillerLinkFailure:

Exercises1.Whichofthefollowingistrueaboutthesignaltransmissionofthesteeringgear?A.thebridge---thesteeringgear---therudderB.therudde---thebridge---thesteeringgearC.thebridge---therudder---steeringgearD.thesteeringgear---therudder---thebridge2.Themainsteeringgearmus