The MV Tacoma went dead in the water off Bainbridge Island in late July because of a voltage surge that fried two fuses after a breaker was opened for the ferry’s Generator 4 as the vessel approached the Bainbridge dock, Washington State Ferries officials said Wednesday.

“We have found the problem, and we have identified a fix for it,” said Lynne Griffith, Assistant Secretary for the state Ferries Division.

It was a never-seen-before problem, said Mark Nitchman, the staff chief engineer of the Tacoma.

It was the first time in the ferry’s 17-year history that such a surge has been seen, Nitchman said.

The Tacoma will be out of service until spring, officials said.

Officials estimate that the repairs to the vessel and its sister ferries will cost $1.8 million.

The Tacoma went dead in the water with more than 400 passengers aboard on the afternoon of Tuesday, July 29 after departing the Seattle terminal for the 12:20 p.m. sailing.

After the ferry lost power, the ship’s crew dropped anchor — the first time in 30 years for a Washington state ferry — on the approach to Bainbridge to prevent the vessel from being beached by the current.

Officials said a flaw in the ship’s design led to the power loss.

A protective device in the circuit breaker control failed, Griffith said, which led to a chain of events that knocked out the ship’s power.

“This was not caused by the way we operate the vessel, nor was it related to any of our maintenance practices,” she said.

Griffith said the technology that would have identified the problem didn’t exist at the time the ship was built in 1997.

A minor design modification will be needed on the Tacoma and its sister ships in the Jumbo Mark II Class to include additional redundancies, Griffith said, so the problem doesn’t happen again.

The repair plan for the Tacoma has been submitted to the Coast Guard. The Coast Guard has to approve the plan before all of the repairs can get underway.