Mechanical problems temporarily sidelined a Steamship Authority boat yet again, forcing the operator to cancel trips between Hyannis and Nantucket on Wednesday morning.

It was the latest failure in a monthslong series of breakdowns that have island residents on Nantucket and neighboring Martha’s Vineyard as well as public officials growing increasingly concerned about the agency’s ability to provide reliable service with the summer season’s unofficial start just a few days away.

In an alert on its website Wednesday morning, the authority said one of the main engines on a boat called the Nantucket lost power Tuesday evening while traveling from Hyannis to Nantucket.

The boat was able to complete that trip, and the problem appeared to be “a clogged fuel strainer.’’

But the vessel was out of commission on Wednesday morning as it underwent Coast Guard inspections and testing, according to the notice.

By late morning Wednesday, the authority said the boat had been repaired, passed testing, and was cleared by the Coast Guard to get back into action, beginning with a noon trip from Hyannis to Nantucket.

Tuesday marked the first day that vessel had returned to service following a $1.6 million repair project.

During just the first four months of this year, the authority canceled some 550 trips because of mechanical problems on its boats — about 15 times its yearly average.

At least six of the 10 vessels in the Steamship Authority’s fleet have been forced to cancel some trips because of mechanical issues so far this year.

However, three boats have accounted for the majority of cancellations: the Martha’s Vineyard, which recently returned from an $18 million mid-life refurbishment project; the Island Home, which recently came back from a $2 million overhaul; and the Woods Hole, which was built just two years ago and ran aground in March.

Most of the canceled trips so far this year have been on routes between Woods Hole in Falmouth and Vineyard Haven on Martha’s Vineyard.

The quasi-public authority’s five-member board two weeks ago voted unanimously to hire outside consultants to conduct an independent review of the agency’s operations.

But that review isn’t scheduled to start until July. That’s because the authority is selecting consultants via a bid process, which will allow several weeks for firms to draft and submit their proposals and for the authority to review them and make a selection.

Matt Rocheleau can be reached at matthew.rocheleau@globe.com.