A vehicle ferry from Portland to Peaks Island broke down on its first run of the day early Friday morning and was expected to be out of commission for most of the day.

The ferry, operated by Casco Bay Lines, had a mechanical problem shortly after it left the mainland at 5:45 a.m., according to operations agent Gary Cressey.

“They realized pretty quickly there was a problem and turned around,” he said.

The ferry had been fixed by about 1:30 p.m., but Casco Bay Lines were still awaiting approval by the U.S. Coast Guard before resuming service. Cressey said he expected the ferry to be running by the end of the work day Friday.

The vehicle ferry operates 16 daily trips and runs later on Friday and Saturday evenings.

Those who could not use the vehicle ferry were transported by passenger ferry, Cressey said. The ferry company also contracted with a private barge to move some vehicles that had been stranded, Cressey said.

Peaks Island is one of several islands off the coast of Portland that is served by Casco Bay Lines. The island is home to a little more than 800 year-round residents.