A Shell Oil drilling ship that slipped its anchor in Alaska's Dutch Harbor raises serious concerns about the company's ability to operate safely in Arctic waters, particularly after the same vessel ran into a mooring problem in New Zealand waters last year, environmental groups said Monday.
The 571-foot Noble Discoverer lost its mooring Saturday, drifting extremely close to shore before it was towed farther offshore and re-anchored. Shell and the Coast Guard say an inspection of the hull by a remotely operated vehicle showed no signs of damage or grounding. Divers will take another look no later than Friday, Shell said. The Coast Guard said it will review findings of both inspections as part of its ongoing investigation.
The Coast Guard said no one was injured in the incident and no pollution has been reported. Coast Guard representatives were expected to board the Discoverer on Monday, Petty Officer Sara Francis said.
The contract ship, owned by Noble Drilling, is among a Shell fleet to head north for planned exploratory offshore drilling in the Arctic waters of the Chukchi and Beaufort seas.
Pamela A. Miller with the Northern Alaska Environmental Center said the incident raises questions about the ship's Arctic capabilities, following the incident off New Zealand in April 2011, when lines in the ship's eight-anchor mooring system failed in a severe storm. The Discoverer was drilling an exploratory well off the South Taranaki coast.
"I'm concerned about the safety of the drilling operation if the rig can't hold in place during a storm in the kinds of conditions we can see in the Chukchi Sea, and the Bering Sea on the way up," Miller said.
Shell spokesman Curtis Smith said only one anchor broke its line and the others held in the New Zealand incident. To ride out the storm in deeper waters, the crew used a system to release the lines as a precautionary measure and moved the vessel. During the anchor disconnection, one of the lines failed to release the first time, but it detached on a second try, Smith said. The anchors and lines dropped to the ocean floor and were later recovered.
"I cannot emphasize enough that protocols and procedures that took place in New Zealand are textbook from our point of view and worked well," Smith said.
Steve Rendle, a spokesman for the government agency Maritime New Zealand, said one anchor cable broke during gale force winds and 36-foot swells. The vessel was repositioned on the seven remaining cables, but two of them broke, he said. The crew had already disconnected from the well when alerted to bad weather approaching, Rendle said in an email. With five mooring cables holding, the Discoverer crew decided to release them and go to more sheltered waters, he said.
"Maritime New Zealand investigated the incident but found no further action was warranted," he said.
Smith noted the spread-anchor system used in New Zealand and to be used in the Arctic is far different than the single harbor anchor used in Dutch Harbor.
Soon after the New Zealand incident, Shell officials said no one was injured and there was no harm to the environment or the well. The company said the vessel sustained minor damage and was repaired.
Drilling in Arctic waters is bitterly opposed by environmental groups and some Alaska Natives. Their lawsuits and permit appeals have prevented Shell Oil from drilling in the Chukchi Sea, where the oil giant spent $2.1 billion on leases in 2008. Shell also holds older leases in the Beaufort Sea and hopes to drill exploratory wells this summer in both locations. The goal is to begin in early August. Smith said.
Shell still needs to get clearance from the Coast Guard to bring up a barge carrying some spill response equipment, according to Smith.
The company also is seeking to change the air permit for the Discoverer after generator engines tested above permit levels for ammonia and nitrous oxide. Shell says it is working with the U.S. Environmental Protection Agency toward a compliance order that would allow the vessel to operate this year and set in motion a review process for the permit changes for 2013 and beyond. Smith said the total emissions for the ship are below allowed levels.
"We have every confidence that the pieces that remain outstanding -- the outstanding permits and certifications -- will arrive," Smith said.
Michael LeVine, an attorney for Oceana, said it appears Shell "got really lucky" in Dutch Harbor. The incident, however, shows yet another reason to question the company's plan, said LeVine, whose organization is among conservation groups that filed a lawsuit against the federal government last week over its approval of oil spill response plans in Shell's Arctic program.
"Luck may be good in Vegas," LeVine said. "But it's not going to work in the Arctic."
Photos: Shell rig drifts near Dutch Harbor 
By RACHEL D'ORO