ANCHORAGE, Alaska (AP) -- One of two drill ships used by Royal Dutch Shell PLC for Arctic drilling off Alaska's coast is under investigation for problems with crew safety and pollution control equipment, the Coast Guard said Thursday.
The Noble Discoverer, owned by Noble Corp., was ordered for more than two weeks to remain in port in Seward while deficiencies were addressed.
The Coast Guard has cleared the vessel to leave for a shipyard in the Pacific Northwest and it likely will begin the trip under tow before the weekend, Shell Alaska spokesman Curtis Smith said.
A Noble Corp. spokesman didn't immediately answer a phone call Thursday, but a statement issued by the company said it is working cooperatively and diligently to rectify deficiencies and maintenance issues raised by the Coast Guard.
Smith said Shell takes the inspection seriously.
"The Noble Discoverer will not deploy to Alaska next season until all of the issues have been corrected," Smith said. He noted the findings were largely associated with the vessel's marine systems and were not related to this year's drilling activities.
"Shell and Noble completed a safe 2012 Alaska exploration season," Smith said.
The Noble Discoverer experienced a vibration problem in its propulsion system after leaving the Chukchi Sea in early November, Smith said. An inspection in the Aleutian Islands port of Dutch Harbor was inconclusive. The vibration problem increased, Smith said, as the vessel continued to Seward, a Prince William Sound port about 75 miles southeast of Anchorage. The vessel is self-propelled but constantly in contact with a tug as it's in transit, he said.
Coast Guard spokesman Kip Wadlow said by phone from Juneau that Capt. Paul Mehler, the officer in charge of marine inspection for western Alaska, assigned inspectors to the Noble Discoverer when it reached Seward in late November.
"The inspectors noticed several major issues regarding crew safety on board the vessel and also some issues with their pollution prevention equipment," he said.
The severity of the discrepancies, Wadlow said, led the Coast Guard to issue a "port stay control detention" for the Liberian-flagged vessel.
"It basically keeps the ship in port until they can get those discrepancies addressed and bring themselves back up into compliance with U.S. and international regulations," Wadlow said.
Wadlow said he could release no more details on the ship's deficiencies. Coast Guard policy, he said, is not to give out additional details during an ongoing investigation.
Of the 16 issues identified, Smith said, six have been addressed and 10 others will be taken care of in the shipyard, likely in Seattle, where the vessel was headed for maintenance. The ship will be towed to the Pacific Northwest, he said.
The 571-foot Noble Discoverer at the end of October had completed preliminary drilling at one well at the Burger-A Prospect 70 miles offshore in the Chukchi Sea, but not without adversity. In July while in Dutch Harbor, the vessel lost its mooring and drifted close to shore. What Smith described as a small, residual fire broke out last month when an engine backfired as the vessel was back in the same harbor.