The ferry Martha’s Vineyard lost power during a Saturday afternoon trip,  triggering a long evening of disruptions and chaos again for the boat line on a busy weekend.

On Sunday morning the Martha's Vineyard cleared sea trials and was put back in service, the Steamship Authority said, but passengers should be prepared for delays throughout the day. The freight ferry Sankaty was brought over from Hyannis to help clear standby lines.

The issue was a fuel problem with the ferry generator, the Steamship Authority said.

Busy but orderly service on Sunday morning on the Vineyard Haven side. — Mark Alan Lovewell

The disruptions began at about 5 p.m. when the Martha’s Vineyard lost power as she was backing out of the slip in Woods Hole. The ferry dropped anchor until it was able to restart its engines and return to the slip. Passengers were left waiting on both sides for about three hours.

Only one slip is available in Woods Hole due to a major reconstruction project on the terminal.  The freight ferry Katama, also disabled due to a failed generator, was occupying the the only available other slip. The boat line had to wait for a tug to move the Katama to make space for the Martha’s Vineyard.

The incident disrupted service during a busy weekend on the Vineyard, with people visiting for the annual Big Chili Contest and other events.

On the Vineyard Haven side lines were long, filled with many Chili Fest revelers, some still wearing big hats and carrying giant inflatable beer bottles. Evelyn Certuchi of Mashpee and Jessica Groman of Falmouth had been working security at the Chili Fest.

Chaos reigned Saturday night as Chili Fest revelers tried to get home. — Mark Alan Lovewell

“After a long day at Chili Fest, it’s annoying,” Ms. Groman said of the delay. They were supposed to be on the 7:15 p.m. boat.

Elizabeth Cutler, visiting from Italy, had been traveling on a ferry leaving Vineyard Haven that had to turn around after the ferry Martha’s Vineyard lost power.

“People thought it was a joke,” Ms. Cutler said. Her guitar case and suitcase were at her feet. She said earlier she played an impromptu concert for the stranded travelers during their hour-long delay.

According to the Steamship Authority, the ferry Katama was later pulled by tug out of its slip, and the Martha's Vineyard moved to that slip under its own power. The ferry Island Home resumed service to Woods Hole with a 7:15 p.m. trip from Vineyard Haven, and the Woods Hole left at about 8:30 p.m.

The Island Home was expected to leave Woods Hole at about 9:15 p.m. followed by the Woods Hole at 9:30 p.m. Both vessels were expected to make one more trip from the Vineyard, at about 10:30 p.m., and the Woods Hole was expected to return to the Vineyard, arriving after midnight and berting in Vineyard Haven for the night.

Vineyard SSA governor Marc Hanover Hanover said Saturday it was unclear why the ferry Martha’s Vineyard lost power. He said the same captain was working on March 17, when the ferry also lost power, that time off East Chop. It had to be towed back to port and kicked off several weeks of ongoing problems with the ferries.

“The word is he’s incredulous,” Mr. Hanover said, speaking about the captain.

He added: “It’s been running just fine for I don’t know how many days. I have no clue what’s happening.” Mr. Hanover has called for an independent investigation into the boat line, but at a meeting on the Vineyard last month, other board members refused to back him, saying any problems could be handled internally.

At about 7:50 p.m. Steamship Authority staff on the Vineyard Haven side announced the Martha’s Vineyard had been towed out of the slip in Woods Hole and ferry service could resume.

Linda and Jim Bowen, visiting from Texas and with hotel reservations in Boston to get to, were in good spirits.

“They’ve done the best they can,” Ms. Bowen said. “We had some excellent scallops at the Black Dog.”

Holly Pretsky contributed reporting.