M/S Coral Carbonic, Power Failure, 3.3.2016

M/S????? Coral?? Carbonic,?????? Power Failure,?????????? 3.3.2016

Overview??????? of???????? Incident?????????

In???????? the?????? afternoon???????? on??????? the?????? 3rd?????? of???????? March? 2016,?? the?????? gas??????????? tanker? Coral Carbonic??????????? was????? anchored???????? in???????? Sk?ldvik,??????????? outer??? anchorage?????? F.???????? The????? pilot???? came?? on board,???????? the??????????? anchor was????? heaved??????????? up??????? and????? the?????? vessel? set?????? off??????????? towards?????????? Sk?ldvik?????????? oil port following????????? the?????? nine-meter??????????? fairway.??????????? About?? an??????? hour???? after??? departure,??????? the vessel suffered?????????? a????????? complete???????? power failure? when?? approaching??? light??????????? buoy Sk?ldvik? ??? 2. The????????? vessel? then???? began to???????? drift.

The????? pilot???? informed????????? Helsinki?????????? VTS???? and????? vessels??????????? in???????? the??????????? vicinity about?? the?????? situation over? the????? VHF radio.?????? The????? vessel??????????? prepared????????? for??????? anchoring.?????? Visibility,????????? weather conditions????? and??????????? the?????? position??????????? of???????? the?????? vessel, however,???????? were??? such??? that??????????? the vessel??????? could?? be??????? let??????? drifting in???????? the?????? fairway.??????????? After??? ten?????? minutes?????????? the?????? engines could? be??????? restarted,???????? and??????????? the?????? vessel? was????? able???? to???????? continue????????? its??????? voyage to???????? port.

Description??? of???????? the?????? power failure and????? its??????? reasons?????????

Shortly before? the?????? power? failure? the?????? vessel’s?????????? radio??? equipment,??????????? sonar?? and the??????????? speed? log?????? began? to???????? flash.?? The????? chief??????????? engineer????????? informed????????? from???? the?????? engine room,?? that????? there??????????? were??? problems with the?????? frequencies.??????????????? Soon??? after this,???????? the vessel? suffered?????????? a????????? total???? black?? out,????? i.e.?????? all??????? equipment??????????? dependent?????? on? electricity,? stopped?????????? working.

The????? regulator????????? in???????? auxiliary?????????? engine 1????????? stopped?????????? working??????????? and????? caused strong oscillation in???? the?????? engine's?????????? rotation??????????? speed. Because????????? both???? auxiliary?????????? engines?????????? were??? connected to the?? main??? switchboard???? at???????? the?????? time???? of???????? the?????? incident,?????????? the??????????? strong? voltage and frequency oscillation??????? affected?????????? the?????? whole??????????? power? distribution?????? system and neither????? of???????? the?????? engine's??????????? circuit?? breakers????????? opened.?????????? After??? the?????? auxiliary?????????? engine stoppage,??????? the?????? circuit?? breaker??????????? of???????? the?????? faulty?? engine could?? be??????????? opened,?????????? and the??????????? operational????? engine was????? restarted.

The????? load???? on??????? the?????? auxiliary?????????? engines?????????? was????? about?? 60??????? kW??????????? at???????? the?????? time???? of???????? the?????? incident, and?? the?????? voltage oscillation??????????? between????????? 400????? and????? 440????? V.

Effects??????????? onboard of???? the?????? power failure

As??????? the?????? vessel’s?????????? 24V????? DC?????? power? system is???????? dependent?????? on??????????? the?????? vessel’s?????????? main electrical system's????????? transformer????? feed,??? the??????????? malfunction????? in???????? the?????? main??? system caused??????????? a????????? great??????????? voltage oscillation??????? in???????? the?????? DC?????? power? system.??????????? The??????????? alarm- and?????? control-systems?????????? of???????? the?????? main??? engine were??????????? disturbed by??? the?????? oscillation, the main??? engine oil??????? pressure??????????? sensor stopped?????????? working,?????????? and????? the?????? main??? engine stopped??????????? due????? to???????? the?????? low?????? oil??????? pressure????????? signal.

When?? the?????? main??? engine stopped,????????? the?????? vessel? lost????? its??????? ability?? to??????????? manoeuvre. Most??????? of???????? the?????? navigation??????? devices,?????????? for??????????? example????????? the?????? radars, stopped?????????? working.?????????? On the navigating??????????? bridge, however,???????? one????? of???????? the?????? VHF???? radios? and????? the??????????? internal? telephone????? remained???????? operational????? and????? enabled??????????? communication.

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The???? emergency???? and????? backup systems??????? and????? their operation

The????? vessel’s?????????? emergency????? generator???????? failed?? to???????? start???? because its??????? starter? relay? did???????? not?????? work.?? All??????? the?????? vessel's?????????? 24V-dependent?????? equipment?????? was????? powered????????? by??????? one 24V????????? DC??????????? power? system.??????????? Normally????????? the?????? equipment?????? got?????? its??????????? power? feed???? from the? main??????????? switchboard,??? through??????????? the??????????? transformer????? and????? rectifier,?????????? or,??????? in???????? the?????? event?? of disturbances,?? from???? the????? emergency????? switchboard.??? In???????? addition,????????? the??????????? DC?????? system has????? a battery????????? supply? (UPS)? for??????? emergency??????????? situations,??????? as??????? well????? as??????? individual batteries????? for??????? a????????? few??????????? devices.?????????????????????? As??????? the?????? emergency????? generator???????? failed?? to??????????? start,?? the?????? electrical????????? system did?????? not?????? get?????? power? from???? the??????????? main??? switchboard,??? or from the?????? emergency????? switchboard.??? The??????????? battery supply? capacity?????????? was????? not?????? sufficient????????? on its?? own. This??????????? resulted?????????? in???????? that????? the?????? voltage of???????? the?????? DC?????? system??????????? decreased????? very? quickly,??? and????? only???? the?????? devices??????????? with??????????? own???? batteries????????? remained operational.

Onboard???????? activities???????? during the?????? power failure

At???????? the?????? time???? of???????? the?????? incident??????????? the?????? master of???????? the??????????? vessel, a????????? watchman??????? and????? the pilot?????????? were??? on??????? the??????????? navigating??????? bridge. The????? vessel's?????????? chief??? engineer????????? and??????????? third engineer? were??? in???????? the?????? engine room.?? The????? master turned? on??????????? the?????? navigation lights????????? for??????? vessels??????????? not?????? under?? command??????????? and????? took over? the? ? hand? steering.????????? The chief???????? mate??? and????? the??????????? watchman??????? were??? sent???? to??????? the?????? bow???? to???????? be??????? prepared??????????? to anchor.?????? The????? pilot???? informed????????? the?????? VTS???? and???? vessels??????????? in???????? the?????? vicinity about?? the?????? incident. The?? pilot???? had????? a??????????? navigation??????? application?????? on??????? a????????? tablet.? That???? made?? it??????????? possible for???? the?????? bridge? team??? to???????? follow?? the?????? direction????????? the??????????? vessel? drifted? in.

The????? vessel’s?????????? chief??? engineer????????? stopped?????????? the?????? auxiliary??????????? engines,????????? opened??????????? the?????? circuit breaker of???????? auxiliary??????????? engine 1????????? and????? restarted????????? auxiliary?????????? engine 2.

Restoring?????? the?????? system??????????? to???????? normal??????????? mode

It????????? took 5-10???????? minutes?????????? to???????? restart? and????? reconnect??????? auxiliary??????????? engine 2????????? to???????? the? main???????? switchboard.??? After??? this????? the??????????? systems?????????? dependent?????? on??????? electricity???????? were largely??? operational??????????? again.? After??? the?????? alarms had????? been??? acknowledged,??????????? the main??????????? engine was????? restarted????????? and????? the?????? vessel? was????? able???? to??????????? continue????????? the?????? voyage towards?????????? port.????

The????? following????????? week, an???????? external?????????? service man,??? commissioned by??????????? the?????? shipping company,????? came?? to???????? the?????? vessel? to???????? try??????? to??????????? clarify?? the?????? reasons?????????? for??????? the power??????? failure? and????? for??????? the??????????? oscillation??????? of???????? the?????? voltage in???????? the?????? auxiliary?????????? engine. The????? regulator????????? in???????? auxiliary?????????? engine 1????????? was????? found?? to???????? be??????????? defective????????? and????? was????? replaced with?? a????????? new.

Entries??????????? in???????? the?????? vessel’s????????? Safety Management? System??????????? (SMS)? concerning???? power failures?????????? and????? their??? implementation

The????? company???????? has???? issued clear??? instructions????? for??????? power? failure??????????? situations.??????? The master????? followed?????????? them??? consistently.

There?? were??? instructions????? for??????? power? failure? situations???????? also???? in???????? the??????????? vessel’s engine?????????? room.?? The????? chief??? engineer????????? deviated??????????? from???? the?????? instructions????? on??????? purpose, once he??????? observed???????? that????? ? the???? emergency???? generator???????? failed?? to???????? start.??? He focused????? on??????????? restarting???????? the?????? auxiliary?????????? engines?????????? rather?? than???? on??????????? trying?? to???????? start???? the emergency?????????? generator???????? manually.

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Factors?????????? that???? reduced????????? safety

·??????? The????? vessel? was????? not?????? under?? command??????? during? the?????? power??????????? failure.

·??????? The????? vessel’s?????????? 24V????? DC?????? power? system was????? common????????? for??????????? all??????? devices dependent????? on electricity,?? including????????? navigation??????????? devices??????????? and????? alarm?? systems.

·??????? The????? backup for??????? the?????? DC?????? system was????? primarily????????? based? on??????????? the?????? functioning of? the emergency?????????? generator.??????? The??????????? battery bank,?? intended????????? to???????? be??????? a secondary backup?? in??????????? case??? of???????? an??????? emergency????? generator???????? failure, was not??????????? alone sufficient??????????? to???????? maintain????????? the?????? power? supply? to??????????? all??????? devices connected????? to???????? the system.

·??????? The????? emergency????? generator???????? did?????? not?????? work.

Factors?????????? that???? increased?????? safety

·??????? The????? pilot???? had????? a????????? navigation??????? application?????? on??????? a??????????? tablet?? that????? was????? not dependent on??????? the?????? vessel's??????????? devices.?????????? That???? made?? it????????? possible?????????? for??????? the??????????? bridge team???? to monitor??????? the?????? vessel’s?????????? position??????????? and??????????? the?????? direction????????? it????????? drifted.

·??????? There?? was????? a????????? pilot???? with????? knowledge?????? about?? the?????? local??????????? circumstances, onboard. He took?????? care???? of???????? the??????????? communication??????????? with????? the?????? VTS???? and????? vessels??????????? in??????????? the vicinity.????? The vessel’s??? crew??? could?? thus???? focus?? on??????????? ensuring????????? the?????? safety? of? the? vessel.

·??????? The????? instructions????? for??????? measures??????? to???????? be??????? taken?? on??????? the??????????? navigating bridge in case??????? of???????? a????????? power? failure? are??????????? clear,?? and????? the?????? crew??? followed them consistently.

External????????? factors??????????? that???? influenced????? positively?????? on??????? the??????????? occasion

·??????? The????? vessel? was????? drifting slowly? in???????? good??? weather?????????? conditions.???????????

·??????? The????? water?? depth?? in???????? the?????? surrounding???? area???? was????? large??????????? enough??????????? to?? allow????????? for safe??????????? drifting of???????? the??????????? vessel.