ANCHORAGE, Alaska (AP) — A damaged floating drill rig and a drill ship that were both involved in Arctic petroleum exploration last summer off Alaska's northern coast will be "dry towed" to shipyards in Asia for assessments and repairs, a Shell Alaska spokesman said Monday.
Dry towing involves loading such cargo on even larger vessels for transport.
The two Royal Dutch Shell PLC vessels are the drill rig Kulluk and drill ship Noble Discoverer.
After summer exploration in the Beaufort Sea, the Kulluk ran aground on New Year's Eve near Kodiak Island as it was being towed to Seattle for maintenance and broke free in a storm. It was refloated and taken to a sheltered harbor.
Once a tow plan is approved, the Kulluk will be towed to Dutch Harbor, then prepared for a dry tow transport to Asia, spokesman Curtis Smith said, adding its Asian destination has not yet been decided.
The Noble Discoverer operated in the Chukchi Sea.
Noble Drilling consulted with Shell and decided to send the drill ship from Seward, Alaska, where it has been docked, to a shipyard in South Korea. The Coast Guard found safety problems with the Noble Discoverer.
Work on the Discoverer originally was to be completed in Washington state, Smith said via email.
"That scope increased due to issues with the main propulsion system on the vessel," he said. "If there is a need to replace that system, including the engine, it would need to be done in a shipyard with a suitable dry dock facility — therefore the change to Korea."
He did not immediately know which Korean shipyard was selected.
Smith estimated it could take three to six weeks "for arrival of the dry tow vessels and pickup of the Kulluk and Discoverer."
Further inspections of both vessels will determine the shipyard schedule and timing of their return to service, Smith said.
Shell has not made any final decision on 2013 drilling in Alaska, he said.
Several investigations and reviews of the 2012 Arctic offshore drilling season are under way.
Last month, Interior Secretary Ken Salazar announced his department would perform an "expedited, high-level assessment" of the summer drilling season.
Salazar said the review would pay special attention to challenges that Shell encountered with the Kulluk, with the Discoverer and with the company's oil spill response barge, which could not obtain certification in time for the drilling season.
Salazar announced the 60-day review shortly after the Coast Guard commander overseeing the Alaska district said he had ordered a formal marine casualty investigation of the Kulluk.
Rear Adm. Thomas Ostebo said the investigation will look at every aspect of the incident, from possible failure of materials to evidence of misconduct, inattention or negligence.
U.S. Sen. Mark Begich, D-Alaska, chairman of the Senate Subcommittee on Oceans, Atmosphere, Fisheries and the Coast Guard, also announced he would conduct a hearing on the grounding.
It's too soon to know the outcome of those investigations, Smith said Monday.
"In the meantime, we are exploring a range of options for exploration work offshore Alaska in 2013," he said. "Shell remains committed to safely exploring for Alaska's offshore energy resources."