EVERETT — The walrus has basked for months in the relative warmth of Port Gardner after an unlucky Alaskan winter.

She’s expected to linger on the waterfront, perhaps through the end of the year, in all of her white and blue metallic splendor.

The walrus visiting the Port of Everett is no tusked marine mammal. The 360-foot ice-class anchor handler is built to tow Arctic oil rigs.

The ship’s given name, Aiviq, means walrus in Inupiaq, a language spoken by northwest Alaska natives.

While physically at a standstill, the Aiviq sits at the center of a federal investigation with multibillion-dollar implications for Arctic oil drilling. The U.S. Coast Guard probe seeks to answer why a massive oil rig the Aiviq was towing last winter broke loose and ran aground in the Gulf of Alaska.

Royal Dutch Shell PLC, which was overseeing the operation, announced in February it would temporarily freeze its Arctic push. In the meantime, the Aiviq is likely to remain tied up in Everett.

“Our future exploration plans for offshore Alaska will depend on a number of factors,” said Megan Baldino, a Shell Alaska spokeswoman. “That includes the readiness of our rigs and confidence that lessons learned from our 2012 drilling program have been fully incorporated.”

At the time of last year’s mishap, the Aiviq was less than a year old. The ship left a Louisiana shipyard in March 2012. Shell had commissioned it from Galliano, La.-based transportation contractor Edison Chouest Offshore.

When the Aiviq was ready, Shell heralded the ship as “one of the most technically advanced polar-class vessels in the world and the first of its kind to be built in the United States.”

The Aiviq headed north.

On Dec. 21, the ship left Dutch Harbor in Alaska’s Aleutian Islands towing a drilling rig called the Kulluk.

The conical-shaped Kulluk is a hulking 266 feet wide with a 160-foot-tall derrick. Designed for icy water, it’s able to drill down 20,000 feet — nearly four miles.

Last fall, crews had used the Kulluk for exploratory drilling north of Prudhoe Bay in the Beaufort Sea, which is frozen over for most of the year.

After the drilling season, the Aiviq began towing the Kulluk toward Seattle for winter maintenance.

On Dec. 27, the Aiviq was pulling the Kulluk through the Gulf of Alaska when the tow line broke during rough seas.

The Alaska Department of Environmental Conservation describes a frustrating chain of events that followed.

The next day, the Aiviq lost power as crews tried to reconnect the tow line. The ship switched to generator power.

The U.S. Coast Guard, the state of Alaska and the marine contractor, Edison Chouest Offshore, sent out response teams who spirited the Kulluk’s 18 crew members to safety.

Over the next several days, the emergency teams failed at repeated attempts to establish a line between the Kulluk, the Aiviq and other vessels.

Strong winds drove the Kulluk aground on New Year’s Eve on Sitkalidak Island, near Kodiak Island. At the time, sea swells reached 35 feet with the wind gusting up to 65 mph.

It took until Jan. 6 to refloat the rig. The Aiviq brought it to safe harbor off Kodiak Island.

The emergency teams deployed booms to control oil leakage, but in the end there was nothing to contain. None of the 150,000 gallons of low-sulfur diesel or other fuels aboard the Kulluk made it into the water, the Coast Guard and Alaska state officials confirmed.

Still, environmentalists said the accident shows the danger of oil drilling in remote areas.

Shell’s leaders also appeared to have had second thoughts.

“We’ve made progress in Alaska, but this is a long-term program that we are pursuing in a safe and measured way,” said Shell president Marvin Odum said in February, when the company announced it would suspend its Arctic program.

The Aiviq arrived in Everett in March.

In May, the Coast Guard conducted nine days of hearings in Anchorage to review the Kulluk’s grounding. Witnesses included representatives of Shell, rig operator Noble Corp., and Aiviq operator Edison Chouest Offshore.

The Coast Guard’s primary concern “is we want to ensure the safety of lives at sea while protecting the environment,” said Chief Petty Officer Kip Wadlow, a spokesman for Coast Guard District 17 in Alaska. “Our key goal is to determine the facts that led to the Kulluk running aground so we can prevent similar incidents in the future.”

The Coast Guard expects to release the report in early 2014.

The U.S. Department of the Interior has already completed a review of the grounding. The report, released in March, criticized Shell for a lack of preparation and poor oversight of contractors.

The Aiviq and the Kulluk are now at opposite ends of the Pacific Ocean.

A heavy lift vessel in March hauled away the Kulluk for repairs in Singapore. The Aiviq arrived in Everett the same month. It may not leave until Shell’s Arctic drilling resumes.

The Associated Press contributed to this report.

Noah Haglund: 425-339-3465, nhaglund@heraldnet.com.