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Precis File
SHIP NAME: Polar Endeavour KEY: NUM. ENTRIES: 4
source Washington State DOE
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Ship was bound from Ferndale to Anacortes refinery. Test was being done on IG equipment. When 300 hp electric motor for IG brought on-line, electrical power was lost. Loss of power then shut down lube oil pumps and subsequently both engines. Redundant/independent engine rooms had been electrically tied in anticipation of spreading the electical load, making them dependent and causing loss of both mains. Reportedly took a minute to reset electrical system and bring engines back on line. Two tugs were escorting the ship at the time of the loss, with one tethered to the stern, and the other running near the bow. Steering and control of the ship was never lost, as electrical power to the wheelhouse and steering system remained avilable throughout the incident from a backup generator.


source Levine, Design and Service Experience on Polar Endeavour Class tankers
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In the second case, the ship was being operated without the plants split. Through a combination of adding loads (i.e. IG blower, engine room ballast pump, fire pump, and deck machinery) while shifting docks, the PCU generators became overloaded. Before the diesel generators came on line the plant blacked out. Power was restored in less than a minute, but the lesson was clear, vessel transits at sea and between docks need to be done with a split plant. [Levine is the Conoco naval architect in charge of designing the Polar Endeavour class. The PCU generators are really a 1000 KW motor-generator set whose job is make sure the power derived from the variable frequency shaft generator is 60 Hz.]


source Puget Sound Pilots Annual Report
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2002-04-15. Polar Endeavor momentary loss of power between Huckleberry and Saddleback Islands. Tug escort ready to assist not needed.


source CTX
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This is an extremely instructive casualty. The Polar ships are a nearly unique attempt at fully independent engine rooms. They meet ABS's highest requirements for redundancy. But the crew apparently felt they did not have enough excess power on one side to run a 300 HP IG fan???? This is obviously a design fault. So they tied the engine rooms together, and they still did not have enough power, even though none of the loads listed by Levine are unusual. If fully independent means anything, this should not be possible. And clearly the ship needed more electrical power both sides. CTX would not be surprised if this were common practice on the ship.

It is doubtful if the ship was able to restore pwoer to both engine rooms in a minute. It is certain that power was not available to the steering system continuously, since there is a delay between the loss of power and the emergency generator coming on line.

If the State DOE report is correct, the pilots summary is at best misleading.

This casualty should have been studied carefully by the USCG, and the detailed results published.

Instead 8 months later in November, 2002, the SF Bay Harbor Safety Committee which includes USCG reps reported that "The Polar Endeavor, with a fully redundant system, has operated for one year with escorts. The vessel has proved itself and has now invoked its right to exemption from tug escorts."