The Steamship Authority is updating its staff training program following an internal investigation of last month’s accident in Woods Hole, where the M/V Sankaty came loose from its slip.

The freight ferry was tethered to shore for the night with five lines, rather than the preferred six, before it drifted free on July 27, boat line general manager Robert Davis said.

“One of the bow lines slid off the [mooring] bollard,” Mr. Davis said at Tuesday’s meeting of the authority’s board of governors. “The other soon followed.”

The vessel came to rest at the nearby Woods Hole Oceanographic Institution dock, with only minor damage and no injuries or environmental consequences, Mr. Davis said.

The Steamship Authority’s training program is being updated to better instruct shore crews on proper tie-up technique and line tension monitoring, he said.

Among other boat line business Tuesday, the board reluctantly agreed to delay the 8:30 p.m. departure from Oak Bluffs by 15 minutes on August 25 through August 27, the three nights of the Beach Road Festival in Vineyard Haven.

The Tisbury select board has asked that the 8:30 p.m. boat be diverted to a Vineyard Haven departure on those nights, Mr. Davis said, as a public safety measure that would assist the town in case of a mass casualty event during the festival.

The Oak Bluffs select board opposed a similar request last year and the 8:30 p.m. boat was delayed, but not diverted. This year, the Oak Bluffs board did not take up the matter.

During last year’s festival, the Steamship Authority had excess capacity on its nighttime trips from Vineyard Haven, said Mr. Davis, who recommended against the diversion.

Vineyard governor James Malkin and Falmouth governor Peter Jeffrey both argued that the boat line should not have to rearrange its schedule to suit a private enterprise.

“We’ve got a schedule that we’ve posted, voted on and accepted, and changing the schedule for a private event that has perhaps sold more capacity than the island or Falmouth has infrastructure to support makes no sense to me,” Mr. Malkin said.

Mr. Jeffrey also expressed dismay that Tisbury officials had not communicated with his town about the potential mass casualty event mentioned in the request signed by select board chair Roy Cutrer.

“I guess their concern is to get everyone off Island and [leave] the town of Falmouth to deal with it,” Mr. Jeffrey said.