HYDROGRAPHY AND HYDROGRAPHIC REPORTS
3000. Introduction
Becausethenauticalchartissoessentialtosafenavi-gation,itisimportantforthemarinertounderstandthecapabilitiesandlimitationsofbothdigitalandpapercharts.Previouschaptershavedealtwithhorizontalandverticaldatums,chartprojections,andotherelementsofcarto-graphicscience.Thischapterwillexplainsomebasicconceptsofhydrographyandcartographywhichareimpor-tanttothenavigator,bothasauserandasasourceofdata.Hydrographyisthescienceofmeasurementanddescrip-tionofallofthefactorswhichaffectnavigation,includingdepths,shorelines,tides,currents,magnetism,andotherfactors.Cartographyisthefinalstepinalongprocesswhichleadsfromrawdatatoausablechartforthemariner.
Themariner,inadditiontobeingtheprimaryuserofhydrographicdata,isalsoanimportantsourceofdatausedintheproductionandcorrectionofnauticalcharts.Thischapterdiscussestheprocessesinvolvedinproducinganauticalchart,whetherindigitalorpaperform,fromtheinitialplanningofahydrographicsurveytothefinalprint-ing.Withthisinformation,themarinercanbetterevaluatetheinformationwhichcomestohisattentionandcanfor-warditinaformthatwillbemostusefultochartingagencies,allowingthemtoproducemoreaccurateanduse-ful charts.
BASICS OF HYDROGRAPHIC SURVEYING
3001. Planning The Survey
Thebasicdocumentsusedtoproducenauticalchartsarehydrographicsurveys.Muchadditionalinformationisincluded,butthesurveyiscentraltothecompilationofachart.Asurveybeginslongbeforeactualdatacollectionstarts. Some elements which must be decided are:
•Exact area of the survey.
•Typeofsurvey(reconnaissanceorstandard)andscale to meet standards of chart to be produced.•Scope of the survey (short or long term).
•Platformsavailable(ships,launches,aircraft,leasedvessels, cooperative agreements).
•Supportworkrequired(aerialorsatellitephotogra-phy, geodetics, tides).
•Limitingfactors(budget,politicaloroperationalconstraints,positioningsystemslimitations,logistics).
Oncetheseissuesaredecided,allinformationavail-ableinthesurveyareaisreviewed.Thisincludesaerialphotography,satellitedata,topographicmaps,existingnau-ticalcharts,geodeticinformation,tidalinformation,andanythingelseaffectingthesurvey.Thesurveyplannersthencompilesoundvelocityinformation,climatology,wa-terclaritydata,anypastsurveydata,andinformationfromlightslists,sailingdirections,andnoticestomariners.Tidalinformationisthoroughlyreviewedandtidegaugeloca-tionschosen.Localverticalcontroldataisreviewedtoseeifitmeetstheexpectedaccuracystandards,sothetidegaugescanbelinkedtotheverticaldatumusedforthesur-vey.Horizontalcontrolisreviewedtocheckforaccuracyanddiscrepanciesandtodeterminesitesforlocalposition-ing systems to be used in the survey.
Linespacingreferstothedistancebetweentrackstoberunbythesurveyvessel.Itischosentoprovidethebestcoverageoftheareausingtheequipmentavailable.Linespacingisafunctionofthedepthofwater,thesoundfoot-printofthecollectionequipmenttobeused,andthecomplexityofthebottom.Oncelinespacingischosen,thehydrographercancomputethetotalmilesofsurveytracktoberunandhaveanideaofthetimerequiredforthesur-vey,factoringintheexpectedweatherandotherpossibledelays.Thescaleofthesurvey,orientationtotheshore-linesinthearea,andthemethodofpositioningdeterminelinespacing.Plannedtracksarelaidoutsothattherewillbenogapsbetweensoundlinesandsufficientoverlapsbe-tween individual survey areas.
Lineswithspacinggreaterthantheprimarysurvey’slinespacingarerunatrightanglestotheprimarysurveyde-velopmenttoverifydatarepeatability.Thesearecalledcross check lines.
Othertaskstobecompletedwiththesurveyincludebottomsampling,seabedcoring,productionofsonarpic-turesoftheseabed,gravityandmagneticmeasurements(ondeepoceansurveys),andsoundvelocitymeasurementsinthe water column.
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412HYDROGRAPHY AND HYDROGRAPHIC REPORTS
3002. Echo Sounders In Hydrographic SurveyingEchosoundersweredevelopedintheearly1920s,andcomputethedepthofwaterbymeasuringthetimeittakesforapulseofsoundtotravelfromthesourcetotheseabot-tomandreturn.Adevicecalledatransducerconvertselectricalenergyintosoundenergyandviceversa.Forbasichydrographicsurveying,thetransducerismountedperma-nentlyinthebottomofthesurveyvessel,whichthenfollowstheplannedtrackline,generatingsoundingsalongthetrack.
Themajordifferencebetweendifferenttypesofechosoundersisinthefrequenciestheyuse.Transducerscanbeclassifiedaccordingtotheirbeamwidth,frequency,andpow-errating.Thesoundradiatesfromthetransducerinacone,withabout50%actuallyreachingtoseabottom.Beamwidthisdeterminedbythefrequencyofthepulseandthesizeofthetransducer.Ingeneral,lowerfrequenciesproduceawiderbeam,andatagivenfrequency,asmallertransducerwillpro-duceawiderbeam.Lowerfrequenciesalsopenetratedeeperintothewater,buthavelessresolutionindepth.Higherfre-quencieshavegreaterresolutionindepth,butlessrange,sothechoiceisatrade-off.Higherfrequenciesalsorequireasmallertransducer.Atypicallowfrequencytransduceroper-ates at 12 kHz and a high frequency one at 200 kHz.
Theformulafordepthdeterminedbyanechosounderis:
D=V------×2
-----T
--+K+Dr
whereDisdepthfromthewatersurface,Vistheaver-agevelocityofsoundinthewatercolumn,Tisround-triptimeforthepulse,Kisthesystemindexconstant,andDristhedepthofthetransducerbelowthesurface(whichmaynotbethesameasvesseldraft).V,Dr,andTcanbeonlygener-allydetermined,andKmustbedeterminedfromperiodiccalibration.Inaddition,Tdependsonthedistinctivenessoftheecho,whichmayvaryaccordingtowhethertheseabot-tomishardorsoft.Vwillvaryaccordingtothedensityofthewater,whichisdeterminedbysalinity,temperature,andpressure,andmayvarybothintermsofareaandtime.Inpractice,averagesoundvelocityisusuallymeasuredonsiteandthesamevalueusedforanentiresurveyunlessvariationsinwatermassareexpected.Suchvariationscouldoccur,forexample,inareasofmajorcurrents.WhileVisavitalfactorindeepwatersurveys,itisnormalpracticetoreflecttheechosoundersignaloffaplatesuspendedundertheshipattypicaldepthsforthesurveyareasinshallowwaters.TheKparam-eter,orindexconstant,referstoelectricalormechanicaldelaysinthecircuitry,andalsocontainsanyconstantcorrec-tionduetothechangeinsoundvelocitybetweentheupperlayersofwaterandtheaverageusedforthewholeproject.Further,vesselspeedisfactoredinandcorrectionsarecom-putedforsettlementandsquat,whichaffecttransducerdepth.Vesselroll,pitch,andheavearealsoaccountedfor.Fi-nally,theobservedtidaldataisrecordedinordertocorrectthe soundings during processing.
Tidesareaccuratelymeasuredduringtheentiresurvey
sothatallsoundingscanbecorrectedfortideheightandthusreducedtothechosenverticaldatum.Tidecorrectionseliminatetheeffectofthetidesonthechartedwatersandensurethatthesoundingsportrayedonthechartaretheminimumavailabletothemarineratthesoundingdatum.Observed,notpredicted,tidesareusedtoaccountforbothastronomicallyandmeteorlogicallyinducedwaterlevelchanges during the survey.3003. Collecting Survey Data
Whilesoundingdataisbeingcollectedalongtheplannedtracklinesbythesurveyvessel(s),avarietyofotherrelatedac-tivitiesaretakingplace.Alarge-scaleboatsheetisproducedwithmanythousandsofindividualsoundingsplotted.Acom-pletenavigationjournaliskeptofthesurveyvessel’sposition,courseandspeed.Side-scansonarmaybedeployedtoinvesti-gateindividualfeaturesandidentifyrocks,wrecks,andotherdangers.Timeistheparameterwhichlinkstheship’spositionwiththevariousechograms,sonograms,journals,andboatsheets that make up the hydrographic data package.3004. Processing Hydrographic Data
Duringprocessing,echogramdataandnavigationaldataarecombinedwithtidaldataandvessel/equipmentcor-rectionstoproducereducedsoundings.Thisreduceddataiscombinedonaplotofthevessel’sactualtracktheboatsheetdatatoproduceasmoothsheet.Acontouroverlayisusuallymadetotestthelogicofallthedatashown.Allano-molousdepthsarerecheckedineitherthesurveyrecordsorinthefield.Ifnecessary,sonardataarethenoverlayedtoan-alyzeindividualfeaturesasrelatedtodepths.Itmaytakedozensofsmoothsheetstocovertheareaofacompletesur-vey.Thesmoothsheetsarethenreadyforcartographers,whowillchooserepresentativesoundingsmanuallyorusingautomatedsystemsfromthousandsshown,toproduceanauticalchart.Documentationoftheprocessissuchthatanyindividualsoundingonanychartcanbetracedbacktoitsoriginal uncorrected value. See Figure 3004.
3005.RecentDevelopmentsInHydrographicSurveyingTheevolutionofechosoundershasfollowedthesamepatternoftechnologicalinnovationseeninotherareas.Inthe1940slowfrequency/widebeamsoundersweredevel-opedforshipstocoverlargeroceanareasinlesstimewithsomelossofresolution.Boatsusedsmallersounderswhichusuallyrequiredvisualmonitoringofthedepth.Later,nar-rowbeamsoundersgaveshipsystemsbetterresolutionusinghigherfrequencies,butwithacorrespondinglossofarea.Thesewerethencombinedintodual-frequencysys-tems.Allechosounders,however,usedasingletransducer,whichlimitedsurveystosinglelinesofsoundings.Forboatequipment, automatic recording became standard.
Thelastthreedecadeshaveseenthedevelopmentofmulti-
HYDROGRAPHY AND HYDROGRAPHIC REPORTS413
Figure 3004. The process of hydrographic surveying.
414HYDROGRAPHY AND HYDROGRAPHIC REPORTS
Figure 3005. Swath versus single-transducer surveys.
HYDROGRAPHY AND HYDROGRAPHIC REPORTS
ple-transducer,multiple-frequencysoundingsystemswhichareabletoscanawideareaofseabed.Twogeneraltypesareinuse.Openwatersarebestsurveyedusinganarrayoftransducersspreadoutathwartshipsacrossthehullofthesurveyvessel.Theymayalsobedeployedfromanarraytowedbehindtheves-selatsomedepthtoeliminatecorrectionsforvesselheave,roll,andpitch.Typically,asmanyas16separatetransducersarear-rayed,sweepinganarcof90°.Theareacoveredbytheseswathsurveysystemsisthusafunctionofwaterdepth.Inshallowwa-ter,tracklinesmustbemuchclosertogetherthanindeepwater.Thisisfinewithhydrographers,becauseshallowwatersneedmorecloselyspaceddatatoprovideanaccurateportrayalofthebottomoncharts.Thesecondtypeofmultiplebeamsystemusesanarrayofverticalbeamtransducersriggedoutonpolesabeamthesurveyvesselwithtransducersspacedtogiveoverlappingcoverageforthegeneralwaterdepth.Thisisanexcellentconfig-urationforveryshallowwater,providingverydenselyspacedsoundingsfromwhichanaccuratepictureofthebottomcanbemadeforharborandsmallcraftcharts.Thewidthoftheswath
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ofthissystemisfixedbythedistancebetweenthetwooutermosttransducers and is not dependent on water depth.
ArecentdevelopmentisAirborneLaserHydrogra-phy(ALH).Anaircraftfliesoverthewater,transmittingalaserbeam.Partofthegeneratedlaserbeamisreflectedbythewater’ssurface,whichisnotedbydetectors.Therestpen-etratestotheseabottomandisalsopartiallyreflected;thisisalsodetected.Waterdepthcanbecomputedfromthediffer-enceintimesofreceiptofthetworeflectedpulses.Twodifferentwavelengthbeamscanalsobeused,onewhichre-flectsoffthesurfaceofthewater,andonewhichpenetratesandisreflectedofftheseabottom.Theobviouslimitationofthissystemiswaterclarity.However,noothersystemcansurveyat200orsomilesperhourwhileoperatingdirectlyovershoals,rocks,reefs,andotherhazardstoboats.Bothpo-larandmanytropicalwatersaresuitableforALHsystems.Depthreadingsupto40metershavebeenmade,andatcer-taintimesoftheyear,some80%oftheworld’scoastalwaters are estimated to be clear enough for ALH.
HYDROGRAPHIC REPORTS
3006. Chart Accuracies
Thechartresultsfromahydrographicsurveycanbenomoreaccuratethanthesurvey;thesurvey’saccuracy,inturn,islimitedbythepositioningsystemused.Formanyoldercharts,thepositioningsystemcontrollingdatacollectioninvolvedus-ingtwosextantstomeasurehorizontalanglesbetweensignalsestablishedashore.Theaccuracyofthismethod,andtoalesserextenttheaccuracyofmodern,shorebasedelectronicposition-ingmethods,deterioratesrapidlywithdistance.Thisoftendeterminedthemaximumscalewhichcouldbeconsideredforthefinalchart.WiththeadventoftheGlobalPositioningSys-tem(GPS)andtheestablishmentofDifferentialGPSnetworks,themarinercannownavigatewithgreateraccuracythancouldthehydrographicsurveyorwhocollectedthechartsourcedata.Therefore,exercisecarenottotakeshoalareasorotherhazardscloseraboardthanwaspastpracticebecausetheymaynotbeexactlywherecharted.Thisisinadditiontothecautionthemarinermustexercisetobesurethathisnavigationsystemandchartareonthesamedatum.Thepotentialdangertothemari-nerincreaseswithdigitalchartsbecausebyzoomingin,hecanincreasethechartscalebeyondwhatcanbesupportedbythesourcedata.Theconstantandautomaticupdateofthevesselspositiononthechartdisplaycangivethenavigatorafalsesenseofsecurity,causinghimtorelyontheaccuracyofachartwhenthesourcedatafromwhichthechartwascompiledcannotsup-port the scale of the chart displayed.
3007. Navigational And Oceanographic InformationMarinersatsea,becauseoftheirprofessionalskillsandlocation,representauniquedatacollectioncapabilityunob-tainablebyanygovernmentagency.Provisionofhighqualitynavigationalandoceanographicinformationbygovernment
agenciesrequiresactiveparticipationbymarinersindatacol-lectionandreporting.Examplesofthetypeofinformationrequiredarereportsofobstructions,shoalsorhazardstonavi-gation,seaice,soundings,currents,geophysicalphenomenasuchasmagneticdisturbancesandsubsurfacevolcanicerup-tions,andmarinepollution.Inaddition,detailedreportsofharborconditionsandfacilitiesinbothbusyandout-of-the-wayportsandharborshelpschartingagencieskeeptheirprod-uctscurrent.TheresponsibilityforcollectinghydrographicdatabyU.S.Navalvesselsisdetailedinvariousdirectivesandinstructions.Civilianmariners,becausetheyoftentraveltoawiderrangeofports,alsohaveanopportunitytocontributesubstantial amounts of information.3008. Responsibility For Information
TheDefenseMappingAgency,theU.S.NavalOcean-ographicOffice(NAVOCEANO),theU.S.CoastGuardandtheCoastandGeodeticSurvey(C&GS)aretheprimaryagencieswhichreceive,process,anddisseminatemarineinformation in the U.S.
DMAprovideschartsandchartupdate(NoticetoMari-ners)andothernauticalmaterialsfortheU.S.militaryservicesand for navigators in general in waters outside the U.S.
NAVOCEANOconductshydrographicandoceano-graphicsurveysofprimarilyforeignorinternationalwaters,anddisseminatesinformationtonavalforces,gov-ernment agencies, and civilians.
TheCoastandGeodeticSurvey(C&GS)conductshy-drographicandoceanographicsurveysandprovideschartsformarineandairnavigationinthecoastalzonesoftheUnited States and its territories.
TheU.S.CoastGuardischargedwithprotectingsafetyoflifeandpropertyatsea,maintainingaidstonavigation,
416HYDROGRAPHY AND HYDROGRAPHIC REPORTS
andimprovingthequalityofthemarineenvironment.Intheexecutionoftheseduties,theCoastGuardcollects,analyz-es, and disseminates navigational and oceanographic data.
Moderntechnologyallowscontemporarynavigatorstocontributetothebodyofhydrographicandoceanographicinformation.
Navigational reports are divided into four categories:1.Safety Reports2.Sounding Reports3.Marine Data Reports4.
Port Information Reports
Theseasandcoastlinescontinuallychangethroughtheactionsofmanandnature.ImprovementsrealizedovertheyearsinthenauticalproductspublishedbyDMAHTC,NOS,andU.S.CoastGuardhavebeenmadepossiblelarge-lybythereportsandconstructivecriticismofseagoingobservers,bothnavalandmerchantmarine.DMAHTCandNOScontinuetorelytoagreatextentonthepersonalob-servationsofthosewhohaveseenthechangesandcancomparechartsandpublicationswithactualconditions.Inaddition,manyoceanareasandasignificantportionoftheworld’scoastalwatershaveneverbeenadequatelysur-veyedforthepurposeofproducingmodernnauticalcharts.
InformationfromallsourcesisevaluatedandusedintheproductionandmaintenanceofDMAHTC,NOSandCoastGuardchartsandpublications.Informationfromsur-veys,whileoriginallyaccurate,issubjecttocontinualchange.Asitisimpossibleforanyhydrographicofficetoconductcontinuousworldwidesurveys,reportsofchangingconditionsdependonthemariner.Suchreportsprovideasteadyflowofvaluableinformationfromallpartsoftheglobe.
Aftercarefulanalysisofareportandcomparisonwithallotherdataconcerningthesameareaorsubject,theorga-nizationreceivingtheinformationtakesappropriateaction.Ifthereportisofsufficienturgencytoaffecttheimmediatesafetyofnavigation,theinformationwillbebroadcastasaSafetyNETorNAVTEXmessage.Eachreportiscomparedwithothersandcontributesinthecompilation,construc-tion,orcorrectionofchartsandpublications.Itisonlythroughtheconstantflowofnewinformationthatchartsand publications can be kept accurate and up-to-date.
AconvenientDataCollectionKitisavailablefreefromDMAHTCandNOSsalesagentsandfromDMAHTCRep-resentatives. The stock number is HYDRODATAKIT.3009. Safety Reports
Safetyreportsarethoseinvolvingnavigationalsafetywhichmustbereportedanddisseminatedbymessage.Thetypesofdangerstonavigationwhichwillbediscussedinthissectionincludeice,floatingderelicts,wrecks,shoals,volcanic activity, mines, and other hazards to shipping.
1.Ice—Marinersencounteringice,icebergs,bergybits,orgrowlersintheNorthAtlanticshouldreporttoCommander,InternationalIcePatrol,Groton,CTthroughaU.S.CoastGuardCommunicationsStation.Directprintingradioteletype(SITOR)isavailablethroughUSCGCom-munications Stations Boston or Portsmouth.
SatellitetelephonecallsmaybemadetotheIcePa-trolofficeinGroton,Connecticutthroughouttheseasonat(203)441-2626(IcePatrolDutyOfficer).MessagescanalsobesentthroughCoastGuardOperationsCenter,Bos-ton at (617) 223-8555.
Whenseaiceisobserved,theconcentration,thickness,andpositionoftheleadingedgeshouldbereported.Thesize,position,and,ifobserved,rateanddirectionofdrift,alongwiththelocalweatherandseasurfacetemperature,shouldbere-portedwhenicebergs,bergybits,orgrowlersareencountered.
Icesightingsshouldalsobeincludedintheregularsyn-opticshipweatherreport,usingthefive-figuregroupfollowingtheindicatorforice.Thiswillassurethewidestdistributiontoallinterestedshipsandpersons.Inaddition,seasurfacetemperatureandweatherreportsshouldbemadetoCOMINTICEPATevery6hoursbyvesselswithinlatitude40°Nand52°Nandlongitude38°Wand58°W,ifaroutineweatherreportisnotmadetoMETEOWashington.2.FloatingDerelicts—Allobservedfloatinganddriftingdangerstonavigationthatcoulddamagethehullorpropellersofavesselatseashouldbeimmediatelyreportedbyradio.Thereportshouldincludeabriefdescriptionofthedanger,thedate, time (GMT) and the location (latitude and longitude).3.Wrecks/Man-MadeObstructions—Informationisneededtoassureaccuratechartingofwrecks,man-madeob-structions,otherobjectsdangeroustosurfaceandsubmergednavigation,andrepeatablesonarcontactsthatmaybeofin-teresttotheU.S.Navy.Man-madeobstructionsnotinuseorabandonedareparticularlyhazardousifunmarkedandshouldbereportedimmediately.Examplesincludeaban-donedwellheadsandpipelines,submergedplatformsandpilings,anddisusedoilstructures.Shipsinkings,strandings,disposals.orsalvagedataarealsoreportable,alongwithanylarge amounts of debris, particularly metallic.
Accuracy,especiallyinposition,isvital:therefore,thedateandtimeoftheobservationoftheobstructionaswellasthemethodusedinestablishingtheposition,andanestimateofthefixaccuracyshouldbeincluded.Reportsshouldalsoincludethedepthofwater,preferablymeasuredbysound-ings(infathomsormeters).Ifknown,thename,tonnage,cargo, and cause of casualty should be provided.
Dataconcerningwrecks,man-madeobstructions,othersunkenobjects,andanysalvageworkshouldbeascompleteaspossible. Additional substantiating information is encouraged.4.Shoals—Whenavesseldiscoversanunchartedorerro-neouslychartedshoaloranareathatisdangeroustonavigation,allessentialdetailsshouldbeimmediatelyreportedto
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DMAHTCWASHINGTONDCviaradio.Anuncharteddepthof300fathomsorlessisconsideredanurgentdangertosubma-rinenavigation.Immediatelyuponreceiptofmessagesreportingdangerstonavigation,DMAHTCissuesappropriateNAVAREAwarnings.Theinformationmustappearonpub-lishedchartsas“reported”untilsufficientsubstantiatingevidence(i.e.clearandproperlyannotatedechogramsandnav-igation logs, and any other supporting information) is received.
Therefore,originatorsofshoalreportsarerequestedtoverifyandforwardallsubstantiatingevidencetoDMAHTCattheearliestopportunity.Itcannotbeoveremphasizedthatclearandproperlyannotatedechogramsandnavigationlogs are especially important in shoal reports.
5.VolcanicActivity—Volcanicdisturbancesmaybeobservedfromshipsinmanypartsoftheworld.Onocca-sion,volcaniceruptionsmayoccurbeneaththesurfaceofthewater.Thesesubmarineeruptionsmayoccurmorefre-quentlyandbemorewidespreadthanhasbeensuspectedinthepast.Sometimestheonlyevidenceofasubmarineerup-tionisanoticeablediscolorationofthewater,amarkedriseinseasurfacetemperature,orfloatingpumice.Marinerswitnessingsubmarineactivityhavereportedsteamswithafoulsulfurousodorrisingfromtheseasurface,andstrangesoundsheardthroughthehull,includingshocksresemblingasuddengrounding.Asubseavolcaniceruptionmaybeac-companiedbyrumblingandhissingashotlavameetsthecold sea.
Insomecases,reportsofdiscoloredwaterattheseasur-facehavebeeninvestigatedandfoundtobetheresultofnewlyformedvolcanicconesontheseafloor.Theseconescangrowrapidly (within a few years) to constitute a hazardous shoal.
Itisimperativethatamarinerreportevidenceofvolca-nicactivityimmediatelytoDMAHTCbymessage.Additional substantiating information is encouraged.6.Mines—Allminesorobjectsresemblingminesshouldbeconsideredarmedanddangerous.Animmediateradio report to DMAHTC should include (if possible):
1.Greenwich Mean Time and date.
2.Position of mine, and how near it was approached.3.Size,shape,color,conditionofpaint,andpresenceof marine growth.
4.Presence or absence of horns or rings.5.Certainty of identification.
3010. Instructions For Safety Report MessagesTheInternationalConventionfortheSafetyofLifeatSea(1974),whichisapplicabletoallU.S.flagships,re-quires:“Themasterofeveryshipwhichmeetswithdangerousice,dangerousderelict,oranyotherdirectdan-gertonavigation,oratropicalstorm,orencounterssubfreezingairtemperaturesassociatedwithgaleforcewindscausingsevereiceaccretiononsuperstructures,or
windsofforce10oraboveontheBeaufortscaleforwhichnostormwarninghasbeenreceived,isboundtocommu-nicatetheinformationbyallmeansathisdisposaltoshipsinthevicinity,andalsotothecompetentauthoritiesatthefirst point on the coast with which he can communicate.”
Thereportshouldbebroadcastfirston2182kHzpre-fixedbythesafetysignal“SECURITE.”Thisshouldbefollowedbytransmissionofthemessageonasuitableworkingfrequencytothepropershoreauthorities.Thetransmissionofinformationregardingice,derelicts,tropi-calstorms,oranyotherdirectdangertonavigationisobligatory.Theforminwhichtheinformationissentisnotobligatory.Itmaybetransmittedeitherinplainlanguage(preferablyEnglish)orbyanymeansofInternationalCodeofSignals(wirelesstelegraphysection).ItshouldbeissuedCQtoallshipsandshouldalsobesenttothefirststationwithwhichcommunicationcanbemadewiththerequestthatitbetransmittedtotheappropriateauthority.Avesselwillnotbechargedforradiomessagestogovernmentau-thorities reporting dangers to navigation.
Eachradioreportofadangertonavigationshouldan-swer briefly three questions:
1.What? A description to of the object or phenomenon.2.Where? Latitude and longitude.
3.When? Greenwich Mean Time (GMT) and date.Examples:Ice
SECURITE.ICE:LARGEBERGSIGHTEDDRIFT-INGSWAT.5KT4605N,4410W,AT0800GMT,MAY15.
Derelicts
SECURITE.DERELICT:OBSERVEDWOODEN25METERDERELICTALMOSTSUBMERGEDAT4406N, 1243W AT 1530 GMT, APRIL 21.
Thereportshouldbeaddressedtooneofthefollowingshore authorities as appropriate:
1.U.S.InlandWaters—CommanderoftheLocalCoast Guard District.
2.OutsideU.S.Waters—DMAHTCWASHINGTON,DC.Wheneverpossible,messagesshouldbetransmittedviathenearestgovernmentradiostation.Ifitisimpracticaltouseagovernmentstation,acommercialstationmaybeused.U.S.governmentnavigationalwarningmessagesshouldinvariablybesentthroughU.S.radiostations,gov-ernmentorcommercial,andneverthroughforeignstations.
Detailedinstructionsforreportingviaradioarecon-tained in DMAHTCPub. 117, Radio Navigation Aids.
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OCEANIC SOUNDING REPORTS
3011. Sounding Reports
Acquisitionofreliablesoundingdatafromalloceanar-easoftheworldisacontinuingeffortofDMAHTC,NAVOCEANO,andNOS.Therearevastoceanareaswherefewsoundingshaveeverbeenacquired.Muchofthebathymetricdatashownonchartshasbeencompiledfrominformationsubmittedbymariners.Continuedcooperationinobservingandsubmittingsoundingdataisabsolutelynecessarytoenablethecompilationofaccuratecharts.Compliancewithsoundingdatacollectionproceduresbymerchantshipsisvoluntary,butforU.S.Navalvesselscompliance is required under various fleet directives.3012. Areas Where Soundings Are Needed
Priortoavoyage,navigatorscandeterminetheimpor-tanceofrecordingsoundingdatabycheckingthechartsfortheroute.Anyshipcrossingadenselysoundedshippinglaneperpendicularornearlyperpendiculartothelanecanobtainveryusefulsoundingdatadespitethedensity.Suchtracksprovidecrosschecksforverifyingexistingdata.Oth-erindicationsthatsoundingsmaybeparticularlyusefulare:
1.Oldsourceslistedonsourcediagramorsourcenoteon chart.
2.Absence of soundings in large areas.
3.Presenceofsoundings,butonlyalongwell-definedlinesindicatingthetrackofthesoundingvessel,with few or no sounding between tracks.4.Legends such as “Unexplored area.”3013. Fix Accuracy
Arealisticgoalofopenoceanpositioningforsoundingreportsis±1nauticalmilewiththecontinuoususeofGPS.However,depthsof300fathomsorlessshouldalwaysbereportedregardlessofthefixaccuracy.Whensuchdepthsareunchartedorerroneouslycharted,theyshouldbereport-edbymessagetoDMAHTCWASHINGTONDC,givingthebestavailablepositioningaccuracy.Echogramsandothersupportinginformationshouldthenbeforwardedbymail to DMAHTC.
TheaccuracygoalnotedabovehasbeenestablishedtoenableDMAHTCtocreateahighqualitydatabasewhichwillsupportthecompilationofaccuratenauticalcharts.Itisparticularlyimportantthatreportscontainthenavigator’sbestestimateofhisfixaccuracyandthatthepositioningaids being used (GPS, Loran C, etc.) be identified.3014. False Shoals
Manypoorlyidentifiedshoalsandbanksshownon
chartsareprobablybasedonencounterswiththeDeepScatteringLayer(DSL),ambientnoise,or,onrareocca-sions,submarineearthquakes.Whileeachappearsrealenoughatthetimeofitsoccurrence,aknowledgeoftheeventsthatnormallyaccompanytheseincidentsmaypre-vent erroneous data from becoming a charted feature.
TheDSLisfoundinmostpartsoftheworld.Itconsistsofaconcentrationofmarinelifewhichdescendsfromnearthesurfaceatsunrisetoanapproximatedepthof200fath-omsduringtheday.Itreturnsnearthesurfaceatsunset.AlthoughattimestheDSLmaybesoconcentratedthatitwillcompletelymaskthebottom,usuallythebottomreturncanbeidentifiedatitsnormaldepthatthesametimetheDSL is being recorded.
Ambientnoiseorinterferencefromothersourcescancauseerroneousdata.Thisinterferencemaycomefromequipmentonboardtheship,fromanothertransducerbeingoperatedcloseby,orfromwaterbornenoise.Mostofthesereturnscanbereadilyidentifiedontheechosounderrecordsandshouldcausenomajorproblems;however,onoccasiontheymaybesostrongandconsistentastoappearas the true bottom.
Finally,avolcanicdisturbancebeneaththeshiporintheimmediatevicinitymaygiveerroneousindicationsofashoal.Theexperiencehasattimesbeendescribedassimilartorunningagroundorstrikingasubmergedobject.Regard-lessofwhetherthefeatureisanactualshoalorasubmarineeruptionthepositions,date/time,andotherinformationshould be promptly reported to DMAHTC.3015. Doubtful Hydrographic Data
Navigatorsarestronglyrequestedtoassistwiththeconfirmationandproperchartingofactualshoalsandtheremovalfromthechartsofdoubtfuldatawhichwaserrone-ously reported.
Theclassificationorconfidencelevelassignedtodoubtfulhydrographicdataisindicatedbythefollowingstandard symbols:AbbreviationMeaning
Rep (date)E.D.Reported (year)Existence DoubtfulP.A.Position ApproximateP.D.
Position Doubtful
Manyofthesereportedfeaturesaresufficientlydeepthatifvalid,ashipcansafelynavigateacrossthearea.Confirmationoftheexistenceofthefeaturewillresultinpropercharting.Ontheotherhand,properlycollectedandannotatedsoundingreportsoftheareamayenableDMAHTCtoaccumulatesufficientevi-dence to justify the removal of the sounding from the chart.
HYDROGRAPHY AND HYDROGRAPHIC REPORTS
3016. Preparation Of Sounding Reports
Theproceduresforpreparingsoundingreportshavebeendesignedtominimizetheeffortsoftheshipboardob-servers,yetprovidetheessentialinformationneededbyDMAHTC.BlankOCEANICSOUNDINGREPORTformsareavailablefromDMAHTCasastockitemorthroughDMARepresentativesinLosAngeles/LongBeach,NewOrleans,andWashington,D.C.Submissionofplottedsoundingtracksisnotrequired.Annotatedechogramsandnavigationlogsarepreferred.Theproce-dureforcollectingsoundingreportsisfortheshiptooperatearecordingechosounderwhiletransitinganareawheresoundingsaredesired.Fixesandcoursechangesarerecordedinthelog,andtheeventmarkerisusedtonotetheseeventsontheechogram.Boththelogandechogramcan then be sent to DMAHTC whenever convenient.
Thefollowingannotationsorinformationshouldbe
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clearlywrittenontheechogramtoensuremaximumuseofthe recorded depths:
1.Ship’sname—Atthebeginningandendofeachrollof echogram or portion.
2.Date—Annotatedat1200hourseachdayandwhenstartingandstoppingtheechosounder,oratleastonce per roll.
3.Time—Theechogramshouldbeannotatedatthebe-ginningofthesoundingrun,atleastonceeachhourthereafter,ateveryscalechange,andatallbreaksintheechogramrecord.Accuracyofthesetimemarksis critical for correlation with ship’s position.
4.TimeZone—GreenwichMeanTime(GMT)shouldbeusedifpracticable.Intheeventlocalzonetimesareused,annotateechogramwheneverclocksarere-setandidentifyzonetimeinuse.Itismostimportantthattheechogramandnavigationlogusethesametime basis.
Figure 3016a. Properly annotated echo sounding record.
Figure 3016b. Typical navigation log for hydrographic reporting.
420HYDROGRAPHY AND HYDROGRAPHIC REPORTS
5.Phaseorscalechanges—Ifechosounderdoesnotindicatescalesettingonechogramautomatically,clearlylabelalldepthphase(ordepthscale)changesandtheexacttimetheyoccur.Annotatetheupperand lower limits of the echogram if necessary.
toverifyexistingdataandmoreaccuratelyportraytheseafloor.ThisishelpfultoourNavalforcesandparticularlytothesubmarinefleet,butisalsousefultogeologists,geo-physicists, and other scientific disciplines.
Areportofoceanicsoundingsshouldcontainthefollowing:
1.AcompletedOceanicSoundingReport,FormDMAHTC 8053/1.
2.A detailed Navigation Log.
3.The echo sounding trace, properly annotated.
Eachpageofthereportshouldbeclearlymarkedwiththeship’snameanddate,sothatitcanbeidentifiedifitbe-comes separated. Mail the report to:
Figure3016aandFigure3016billustratesthedatanecessarytoreconstructasoundingtrack.Ifshipopera-tionsdictatethatonlyperiodicsinglepingsoundingscanbeobtained,thedepthsmayberecordedintheRemarkscolumn.AproperlyannotatedechogramisalwaysstronglypreferredbyDMAHTCoversinglepingsound-ingswheneveroperationspermit.Thenavigationlogisvitaltothereconstructionofasoundingtrack.Withoutthepositioninformationfromthelog,theechogramisvirtually useless.
ThedatareceivedfromthesereportsisdigitizedandbecomespartofthedigitalbathymetricdatalibraryofDMAHTC.Thislibraryisusedasthebasisofnewchartcompilation.Eveninareaswherenumeroussoundingsal-readyexist,soundingreportsallowvaluablecross-checking
Director
DMA Hydrographic/Topographic CenterMC, D-40
4600 Sangamore Rd.
Bethesda, MD, 20816-5003
OTHER HYDROGRAPHIC REPORTS
3017. Marine Information Reports
MarineInformationReportsarereportsofitemsofnavigational interest such as the following:
1.2.3.4.5.6.
Discrepancies in published information.Changes in aids to navigation.Electronic navigation reports.Satellite navigation reports.Radar navigation reports.Magnetic disturbances.
objects,thepositionmaybeexpressedasbearingsandrangesfromthem.Bearingsshouldpreferablybe reported as true and expressed in degrees.
5.Alwaysreportthelimitingbearingsfromtheshiptowardthelightwhendescribingthesectorsinwhichalightiseithervisibleorobscured.Althoughthisisjustthereverseoftheformusedtolocateob-jects,itisthestandardmethodusedonDMAHTCnautical charts and in Light Lists.
6.Areportpreparedbyonepersonshould,ifpossible,be checked by another.Inmostcasesmarineinformationcanbeadequatelyre-portedononeofthevariousformsprintedbyDMAHTCorNOS.ItmaybemoreconvenienttoannotateinformationdirectlyontheaffectedchartandmailittoDMAHTC.Asanexample,itmaybeusefultosketchunchartedorerrone-ouslychartedshoals,buildings,orgeologicalfeaturesdirectlyonthechart.Appropriatesupportinginformationshould also be provided.
DMAHTCforwardsreportsapplicabletoNOS,NAV-OCEANO,orCoastGuardproductstotheappropriateagency.
Reportsbyletterarejustasacceptableasthosepre-paredonregularforms.Aletterreportwilloftenallowmoreflexibilityinreportingdetails,conclusions,orrecom-mendationsconcerningtheobservation.Whenreportingontheregularforms,ifnecessaryuseadditionalsheetstocom-plete the details of an observation.
Reportsarerequiredconcerninganyerrorsininformation
Reportanymarineinformationwhichyoubelievemaybeusefultochartingauthoritiesorothermariners.Dependingonthetypeofreport,certainitemsofinfor-mationareabsolutelycriticalforacorrectevaluation.Thefollowinggeneralsuggestionsareofferedtoassistinreporting information that will be of maximum value:
1.Thegeographicalpositionincludedinthereportmaybeusedtocorrectcharts.Accordingly,itshouldbefixedbythemostexactmethodavailable,more than one if possible.
2.Ifgeographicalcoordinatesareusedtoreportposi-tion,theyshouldbeasexactascircumstancespermit.Referenceshouldbemadetothechartbynumber, edition number, and date.
3.Thereportshouldstatethemethodusedtofixtheposition and an estimate of fix accuracy.
4.Whenreportingapositionwithinsightofcharted
HYDROGRAPHY AND HYDROGRAPHIC REPORTS
publishedonnauticalchartsorinnauticalpublications.Theportsshouldbeasaccurateandcompleteaspossible.Thiswillresultincorrectionstotheinformationincludingtheissuanceof Notice to Mariners changes when appropriate.
Reportallchanges,defects,establishmentordiscon-tinuanceofnavigationalaidsandthesourceoftheinformation.Checkyourreportagainstthelightlist,listoflights,RadioAidstoNavigation,andthelargestscalechartofthearea.Ifitisdiscoveredthatanewlighthasbeenes-tablished,reportthelightanditscharacteristicsinaformatsimilartothatcarriedinlightlistsandlistsoflights.Forchangesanddefects,reportonlyelementsthatdifferwithlightlists.Ifitisalightedaid,identifybynumber.De-fectiveaidstonavigationinU.S.territorialwatersshouldbereportedimmediatelytotheCommanderofthelocalCoast Guard District.
3018. Electronic Navigation Reports
ElectronicnavigationsystemssuchasGPSandLO-RANhavebecomeanintegralpartofmodernnavigation.Reportsonpropagationanomaliesoranyunusualreceptionwhile using the electronic navigation system are desired.
Information should include:
1.Typeofelectronicnavigationsystemandchannelor frequency used.
2.Type of antenna: whip, vertical or horizontal wire.3.Transmitting stations, rate or pair used.4.Nature and description of the reception.5.Type of signal match.6.Date and time.
7.Position of own ship.
8.Manufacturer and model of receiver.
CalibrationinformationisbeingcollectedinanefforttoevaluateandimprovetheaccuracyoftheDMAHTCde-rivedLoransignalpropagationcorrectionsincorporatedinNationalOceanServiceCoastalLoranCcharts.LoranCmonitordataconsistingofreceiverreadingswithcorre-spondingwelldefinedreferencepositionsarerequired.MarinersaboardvesselsequippedwithLoranCreceivingunitsandhavingprecisepositioningcapabilityindependentoftheLoranCsystem(i.e.,dockedlocationsorvisualbear-ings,radar,GPS,Raydist,etc.)arerequestedtoprovideinformation to DMAHTC.
3019. Radar Navigation Reports
421
Reportsofanyunusualreceptionoranomalouspropaga-tionbyradarsystemscausedbyatmosphericconditionsareespeciallydesirable.Commentsconcerningtheuseofradarinpiloting,withthelocationsanddescriptionofgoodradartargets, are particularly needed. Reports should include:
1.2.3.4.5.
Type of radar, frequency, antenna height and type.Manufacturer and model of the radar.
Date, time and duration of observed anomaly.Position.
Weather and sea conditions.
Radarreceptionproblemscausedbyatmosphericpa-rametersarecontainedinfourgroups.Inadditiontothepreviouslylisteddata,reportsshouldincludethefollowingspecific data for each group:
1.Unexplainedechoes—Descriptionofecho,appar-entvelocityanddirectionrelativetotheobserver,and range.
2.Unusual clutter—Extent and Sector.
3.Extendeddetectionranges—Surfaceorairbornetarget,whetherpointordistributedtarget,suchasacoastline or landmass.
4.Reduceddetectionranges—Surfaceorairbornetarget,whetherpointordistributedtarget,suchasacoastline or landmass.3020. Magnetic Disturbances
Magneticanomalies,theresultofavarietyofcauses,existinmanypartsoftheworld.DMAHTCmaintainsarecordofsuchmagneticdisturbancesandwheneverpossi-bleattemptstofindanexplanation.Abetterunderstandingofthisphenomenoncanresultinmoredetailedchartswhich will be of greater value to the mariner.
Thereportofamagneticdisturbanceshouldbeasspe-cificaspossible,forinstance:“Compassquicklyswung190°to170°,remainedoffsetforapproximately3minutesandslowlyreturned.”Includeposition,ship’scourse,speed, date, and time.
Wheneverthereadingsofthestandardmagneticcom-passareunusual,anazimuthcheckshouldbemadeassoonaspossibleandthisinformationforwardedtoDMAHTC.
PORT INFORMATION REPORTS
3021. Importance Of Port Information ReportsPortInformationReportsprovideessentialinforma-tionobtainedduringportvisitswhichcanbeusedtoupdate
andimprovecoastal,approach,andharborchartsaswellasnauticalpublicationsincludingSailingDirections,CoastPilots,andFleetGuides.Engineeringdrawings,hydro-graphicsurveysandportplansshowingnewconstruction
422HYDROGRAPHY AND HYDROGRAPHIC REPORTS
affecting charts and publications are especially valuable.
Itemsinvolvingnavigationsafetyshouldbereportedbymessage.Itemswhicharenotofimmediateurgency,aswellasadditionalsupportinginformationmaybesubmittedbythePortInformationReport(DMAHTCForm8330-1),ortheNoticetoMarinersMarineInformationReportandSuggestionSheetfoundinthebackofeachNoticetoMar-iners.Reportsbyletterarecompletelyacceptableandmaypermit more reporting flexibility.
Insomecasesitmaybemoreconvenientandmoreef-fectivetoannotateinformationdirectlyonachartandmailittoDMAHTC.Asanexample,newconstruction,suchasnewportfacilities,pierorbreakwatermodifications,etc.,maybedrawnonachartincaseswhereawrittenreportwould be inadequate.
SpecificNavyreportingrequirementsexistforshipsvis-itingforeignports.ThesereportsareprimarilyintendedtoprovideinformationforuseinupdatingtheNavyPortDirec-tories.AcopyofthenavigationinformationresultingfromportvisitsshouldbeprovideddirectlytoDMAHTCbyinclud-ingDMAHTCWASHINGTONDC/MCC//asanINFOaddressee on messages containing hydrographic information.3022. What To Report
Coastalfeaturesandlandmarksarealmostconstantlychanging.Whatmayatonetimehavebeenamajorland-markmaynowbeobscuredbynewconstruction,destroyed,orchangedbytheelements.SailingDirections(Enroute)andCoastPilotsutilizealargenumberofphotographsandlinesketches.Photographs,particularlyaseriesofoverlap-pingviewsshowingthecoastline,landmarks,andharborentrancesareveryuseful.Photographsandnegativescanbeused directly as views or in the making of line sketches.
Thefollowingquestionsaresuggestedasaguideinpreparingreportsoncoastalareasthatarenotincludedorthat differ from the Sailing Directions and Coast Pilots.
Approach
1.What is the first landfall sighted?
2.Describethevalueofsoundings,radiobearings,GPS,LORAN,radarandotherpositioningsystemsinmakingalandfallandapproachingthecoast.Aredepths,curves,andcoastaldangersaccuratelycharted?
3.Areprominentpoints,headlands,landmarks,andaidstonavigationadequatelydescribedinSailingDirectionsandCoastPilots?Aretheyaccuratelycharted?
4.Dolandhazes,fogorlocalshowersoftenobscurethe prominent features of the coast?
5.Dodiscoloredwateranddebrisextendoffshore?Howfar?Weretidalcurrentsorripsexperiencedalongthecoastsorinapproachestoriversorbays?6.Are any features of special value as radar targets?
Tides and Currents
1.Are the published tide and current tables accurate?2.Doesthetidehaveanyspecialeffectsuchasriverbore?Istherealocalphenomenon,suchasdoublehigh or low water interrupted rise and fall?
3.Wasanyspecialinformationontidesobtainedfrom local sources?
4.Whatisthesetanddriftoftidalcurrentsalongcoasts,aroundheadlandsamongislands,incoastalindentations?
5.Aretidalcurrentsreversingorrotary?Ifrotary,dotheyrotate in a clockwise or counterclockwise direction?6.Dosubsurfacecurrentsaffectthemaneuveringofsurface craft? If so, describe.
7.Arethereanycountercurrents,eddies,overfalls,ortide rips in the area? If so, locate.River and Harbor Entrances
1.Whatisthedepthofwateroverthebar,andisitsubjecttochange?Wasaparticularstageoftidenecessary to permit crossing the bar?
2.Whatistheleastdepthinthechannelleadingfromsea to berth?
3.Ifthechannelisdredged,whenandtowhatdepthand width? Is the channel subject to silting?
4.Whatisthemaximumdraft,length,andwidthofavessel that can be taken into port?
5.Ifsoundingsweretaken,whatwasthestageoftide?Werethesoundingstakenbyechosounderorleadline?Ifthedepthinformationwasreceivedfrom other sources, what were they?
6.Whatwasthedateandtimeofwaterdepthobservations?Hills, Mountains, and Peaks
1.Arehillsandmountainsconical,flat-topped,orofany particular shape?
2.At what range are they visible in clear weather?3.Are they snowcapped throughout the year?4.Are they cloud-covered at any particular time?5.Arethesummitsandpeaksadequatelycharted?Canaccuratedistancesand/orbearingsbeob-tained by sextant, pelorus, or radar?6.What is the quality of the radar return?Pilotage
1.Where is the signal station located?
2.Wheredoesthepilotboardthevessel?Arespecialarrangements necessary before a pilot boards?3.Is pilotage compulsory? Is it advisable?
4.Willapilotdirectashipinatnight,duringfoulweather, or during periods of low visibility?
HYDROGRAPHY AND HYDROGRAPHIC REPORTS
423
5.Where does the pilot boat usually lie?
6.Doesthepilotboatchangestationduringfoulweather?
7.Describetheradiotelephonecommunicationfacili-tiesavailableatthepilotstationorpilotboat.Whatisthecall-sign,frequency,andthelanguagespoken?General
1.Whatcautionaryadvice,additionaldata,andinfor-mationonoutstandingfeaturesshouldbegiventoa mariner entering the area for the first time?
2.AtanytimedidaquestionorneedforclarificationarisewhileusingDMAHTC,NOS,orCoastGuardproducts?
3.Werechartedlandcontoursusefulwhilenavigatingusingradar?Indicatethechartsandtheireditionnumbers.
4.Woulditbeusefultohaveradartargetsortopo-graphicfeaturesthataidinidentificationorpositionplottingdescribedorportrayedintheSail-ing Directions and Coast Pilots?Photographs
Theoverlappingphotographmethodforpanoramicviewsshouldbeused.Onthebackofthephotograph(neg-ativesshouldaccompanytherequiredinformation),indicatethecamerapositionbybearinganddistancefromafixed,chartedobjectifpossible,nameofthevessel,thedate,timeofexposure,andheightoftide.Allfeaturesofnavigationalvalueshouldbeclearlyandaccuratelyidenti-fiedonanoverlay,iftimepermits.Bearingsanddistances(fromthevessel)ofunchartedfeatures,identifiedontheprint, should be included.
Radarscope Photography
Becauseofthevalueofradarasanaidtonavigation,DMAHTCdesiresradarscopephotographs.GuidelinesforradarsettingsforradarscopephotographyaregiveninRa-darNavigationManual,Pub.1310.Suchphotographs,reproducedintheSailingDirectionsandFleetGuides,sup-plementtextualinformationconcerningcriticalnavigationalareasandassistthenavigatorincorrelatingtheradarscopepresentationwiththechart.Tobeofthegreatestvalue,radarscopephotographsshouldbetakenatlandfalls,seabuoys,harborapproaches,majorturnsinchannels,con-structedareasandotherplaceswheretheywillmostaidthenavigator.Twoglossyprintsofeachphotographareneed-ed. One should be unmarked, the other annotated.
Examplesofdesiredphotographsareimagesoffixedandfloatingnavigationalaidsofvarioussizesandshapesasobservedunderdifferentseaandweatherconditions,andimagesofseareturnandprecipitationofvariousintensities.
Thereshouldbetwophotographsofthistypeofimage,onewithouttheuseofspecialanticluttercircuitsandanothershowingremedialeffectsofthese.Photographsofactualicebergs,growlers,andbergybitsunderdifferentseacon-ditions,correlatedwithphotographsoftheirradarscopeimages are also desired.
Radarscopephotographsshouldincludethefollowingannotations:
1.Wavelength.
2.Antenna height and rotation rate.3.Range-scale setting and true bearing.
4.Antenna type (parabolic, slotted waveguide).5.Weather and sea conditions, including tide.6.Manufacturer’s model identification.7.Position at time of observation.
8.
IdentificationoftargetbyLightList,ListofLights,or chart.
9.Camera and exposure data.Other desired annotations include:1.Beam width between half-power points.2.Pulse repetition rate.3.Pulse duration (width).4.Antenna aperture (width).5.Peak power.6.Polarization.
7.
Settingsofradaroperatingcontrols,particularlyuse of special circuits.
8.Characteristicsofdisplay(stabilizedorunstabi-lized), diameter, etc.Port Regulations and Restrictions
SailingDirections(PlanningGuides)areconcernedwithpratique,pilotage,signals,pertinentregulations,warn-ingareas,andnavigationalaids.UpdatedandnewinformationisconstantlyneededbyDMAHTC.Portinfor-mationisbestreportedontheprepared“PortInformationReport”,DMAHTCform8330-1.Ifthisformisnotavail-able,thefollowingquestionsaresuggestedasaguidetotherequested data.
1.Is this a port of entry for overseas vessels?
2.Ifnotaportofentrywheremustvesselgoforcus-toms entry and pratique?
3.Wheredocustoms,immigration,andhealthoffi-cials board?
4.What are the normal working hours of officials?5.Willtheofficialsboardvesselsafterworkinghours?Are there overtime charges for after-hour services?6.Iftheofficialsboardavesselunderway,dotheyre-main on board until the vessel is berthed?7.Were there delays? If so, give details.
8.Were there any restrictions placed on the vessel?
424HYDROGRAPHY AND HYDROGRAPHIC REPORTS
9.WasacopyofthePortRegulationsreceivedfromthe local officials?
10.Whatverbalinstructionswerereceivedfromthelo-cal officials?
11.Whatpreparationspriortoarrivalwouldexpediteformalities?
12.Arethereanyunwrittenrequirementspeculiartothe port?
13.What are the speed regulations?
14.What are the dangerous cargo regulations?
15.Whataretheflammablecargoandfuelingregulations?.
16.Aretherespecialrestrictionsonblowingtubes,pumping bilges. oil pollution, fire warps, etc.?17.Aretherestrictedandanchorageareascorrectlyshownoncharts,anddescribedintheSailingDi-rections and Coast Pilots?
18.Whatisthereasonfortherestrictedareas;gunnery,aircraft operating, waste disposal, etc.?
19.Aretherespecifichoursofrestrictions,orarelocalblanket notices issued?
20.Isitpermissibletopassthrough,butnotanchorin,restricted areas?
21.Dofishingboats,stakes,nets,etc.,restrictnavigation?
22.Whataretheheightsofoverheadcables,bridges,and pipelines?
23.Whatarethelocationsofsubmarinecables,theirlanding points, and markers?
24.Arethereferrycrossingsorotherareasofheavylo-cal traffic?
25.Whatisthemaximumdraft,length,andbreadthofa vessel that can enter?Port Installations
MuchoftheportinformationwhichappearsintheSailingDirectionsandCoastPilotsisderivedfromvisitreportsandportbrochuressubmittedbymariners.Com-mentsandrecommendationsonenteringportsareneededsothatcorrectionstothesepublicationscanbemade.
Ifextracopiesoflocalportplans,diagrams,regula-tions,brochures,photographs,etc.,canbeobtained,sendthemtoDMAHTC.ItisnotessentialthattheybeprintedinEnglish.Localpilots,customsofficials,companyagents,etc., are usually good information sources.
MuchofthefollowinginformationisincludedintheregularPortInformationReport,butmaybeusedasacheck-off list when submitting a letter report.
General
1.Name of the port.
2.Date of observation and report.3.Name and type of vessel.
4.Gross tonnage.5.Length (overall).6.Breadth (extreme).7.Draft (fore and aft).
8.Name of captain and observer.
9.
U.S. mailing address for acknowledgment.
Tugs and Locks
1.Aretugsavailableorobligatory?Whatistheirpower?
2.Iftherearelocks,whatisthemaximumsizeanddraft of a vessel that can be locked through?
Cargo Handling Facilities
1.Whatarethecapacitiesofthelargeststationary,mobile,andfloatingcranesavailable?Howwasthis information obtained?
2.Whatarethecapacities,types,andnumberoflight-ers and barges available?
3.Isspecialcargohandlingequipmentavailable(e.g.)grainelevators,coalandoreloaders,fruitorsugarconveyors, etc.?
4.Ifcargoishandledfromanchorage,whatmethodsareused?Whereisthecargoloaded?Arestoragefacilities available there?Supplies
1.Arefueloils,dieseloils,andlubricatingoilsavail-able? If so, in what quantity?
Berths1.Whatarethedimensionsofthepier,wharf,orbasinused?
2.Whatarethedepthsalongside?Howweretheyobtained?
3.Describeberth/berthsforworkingcontainersorroll-on/ roll-off cargo.
4.Doestheporthaveberthforworkingdeepdrafttankers? If so, describe.
5.Whatstoragefacilitiesareavailable,bothdryandrefrigerated?
6.Areanyunusualmethodsusedwhendocking?Arespecial precautions necessary at berth?Medical, Consular, and Other Services
1.Isthereahospitalortheservicesofadoctoranddentist available?
2.IsthereaUnitedStatesconsulate?Whereisitlo-cated? If none, where is the nearest?
HYDROGRAPHY AND HYDROGRAPHIC REPORTS
Anchorages
1.What are the limits of the anchorage areas?2.In what areas is anchorage prohibited?
3.Whatisthedepth,characterofthebottom,typesofholdingground,andswingingroomavaiable?
4.Whataretheeffectsofweather,sea,swell,tides,currents on the anchorages?
5.Where is the special quarantine anchorage?6.Are there any unusual anchorage restrictions?
Repairs and Salvage
425
1.Whatarethecapacitiesofdrydocksandmarinerailways, if available?
2.Whatrepairfacilitiesarcavailable?Arethererepairfacilities for electrical and electronic equipment?3.Are divers and diving gear available?
4.Aretheresalvagetugsavailable?Whatisthesizeand operating radius?
5.Areanyspecialservices,(e.g.,compasscompensa-tion or degaussing,) available?
MISCELLANEOUS HYDROGRAPHIC REPORTS
3023. Ocean Current Reports
Thesetanddriftofoceancurrentsareofgreatconcerntothenavigator.Onlywiththecorrectcurrentinformationcantheshortestandmostefficientvoyagesbeplanned.Aswithallforcesofnature,mostcurrentsvaryconsiderablywithtimeatagivenlocation.Therefore,itisimperativethatDMAHTCreceiveoceancurrentreportsonacontinuousbasis.
Thegeneralsurfacecurrentsalongtheprincipaltraderoutesoftheworldarewellknown;however,inotherlesstraveledareasthecurrenthasnotbeenwelldefinedbecauseofthelackofinformation.Detailedcurrentreportsfromthose areas are especially valuable.
Anurgentneedexistsformoreinshorecurrentreportsalongallcoastsoftheworldbecausedataintheseregionsarescarce.Furthermore,informationfromdeepdraftshipsisneededasthistypeofvesselissignificantlyinfluencedbythe deeper layer of surface currents.
TheCURRENTREPORTform,NAVOCEANO3141/6,isdesignedtofacilitatepassinginformationtoNAVOCEANOsothatallmarinersmaybenefit.Theformisself-explanatoryandcanbeusedforoceanorcoastalcur-rentinformation.Reportsbythenavigatorwillcontributesignificantlytoaccuratecurrentinformationfornauticalcharts,CurrentAtlases,PilotCharts,SailingDirectionsand
other special charts and publications.3024. Route Reports
RouteReportsenableDMAHTC,throughitsSailingDirections(PlanningGuides),tomakerecommendationsforoceanpassagesbasedupontheactualexperienceofmariners.Ofparticularimportancearereportsofroutesusedbyverylargeshipsandfromanyshipinregionswhere,fromexperienceandfamiliaritywithlocalcondi-tions,marinershavedevisedroutesthatdifferfromthe“preferredtrack.”Inaddition,becauseofthemanyandvar-iedlocalconditionswhichmustbetakenintoaccount,coastalrouteinformationisurgentlyneededforupdatingboth Sailing Directions and Coast Pilots.
ARouteReportshouldincludeacomprehensivesum-maryofthevoyagewithreferencetocurrents,dangers,weather,andthedraftofthevessel.Ifpossible,eachreportshouldanswerthefollowingquestionsandshouldincludeanyotherdatathatmaybeconsideredpertinenttothepar-ticularroute.Allinformationshouldbegiveninsufficientdetailtoassureaccurateconclusionsandappropriaterec-ommendations. Some questions to be answered are:
1.Why was the route selected?
2.Were anticipated conditions met during the voyage?
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