The Alaska state ferry Columbia — which has been out of service since late November for its annual overhaul and repairs but was supposed to go back to work this summer — will be laid up until the end of the year.

Extensive corrosion in the 51-year-old ship’s fire suppression system is the reason for the extra time in the shipyard, Department of Transportation spokesman Sam Dapcevich said Friday.

During the Columbia’s extended absence, the Alaska Marine Highway System has diverted the Kennicott out of layup for the weekly run between Bellingham, Washington, and Southeast Alaska. The route carries more passengers and vehicles than other runs, particularly during the summer visitor season.

The two ferries can carry about the same number of passengers, close to 500, but the Kennicott has about 40% less deck space than the Columbia for cars, trucks and RVs.

The smaller carrying capacity for vehicles could be a problem for travelers who have not made a reservation yet. A search of the ferry system booking website on May 19 to bring a vehicle from Bellingham to Wrangell shows nothing available until the Aug. 9 sailing from Puget Sound.

The Columbia operated for most of 2023 after it was held out of service for more than three years. “The vessel was taken out of service in 2019 as a cost-control measure,” the Department of Transported reported.

The ship had been scheduled to return to the Bellingham-to-Southeast run this month, with the Kennicott going into layup status for the second summer in a row due to a lack of crew to fully staff the ferry. The Alaska Marine Highway has been plagued by crew shortages the past three years.

Much of the Columbia’s crew was transferred this month to serve on the Kennicott.

Dapcevich said the plan is to bring the Columbia back into service toward the end of this year when the Kennicott heads into the shipyard for a year-long project to reduce its emissions to meet federal standards.

“When the Columbia’s repairs are complete, some downtime would be required to transfer crew — which creates a scenario of no mainliner service in Southeast for a couple of weeks” later this year, he said.

The ferry system will release its fall schedule later this summer.

The state expects the Kennicott will be in a shipyard for 10 months next year for EPA-required generator replacements, Dapcevich said, adding that the ferry system will need to rely on the Columbia for “a full year of service in 2025.”

When the Kennicott is cleared to resume sailing after getting new generators, the Columbia will take its turn in the shipyard for rebuilding of its controllable-pitch propellers system.

The state had previously bid out the work for the Columbia but did not receive any qualified bids and will try again, Dapcevich said.