The Fauntleroy/Vashon/Southworth ferry service was reduced to a two-boat schedule until further notice Saturday afternoon after a third vessel on that route experienced mechanical problems, according to Washington State Ferries.

Drivers departing Vashon Island were told to expect delays of up to an hour because of the vessel shortage. There was no immediate word on how long the extended waits would last.

The problem vessel, the Evergreen State, is Washington’s oldest ferry. Built in 1954, the 87-car ferry was decommissioned June 29 only to be brought back two weeks later to replace another out-of-service vessel.

Saturday’s mechanical issue comes a day after a Bremerton-Seattle ferry had to turn back because crew loaded 484 more passengers than its official capacity of 1,200 allows, causing delays on that route.

A spokeswoman for Washington State Ferries could not be reached for comment.