PORTLAND, Maine — The same day a mechanical failure knocked out car ferry service to Peaks Island — and two weeks after a ferry crashed into a pier in New York, injuring 74 people — Casco Bay Lines’ operations manager and City Councilor Nicholas Mavodones Jr. on Monday said ferry riders should feel safe knowing the vessels have a “robust preventive maintenance program.”

The car ferry, the 35-year-old Machigonne II, had an electrical malfunction Monday afternoon that required a new part, Mavodones said. While the ship was offline Monday and Tuesday, service to Peaks was being provided by Lionel Plante Associates, a marine services company based on the island, according to a post on the Casco Bay Lines’ Facebook page.

The New York accident occurred on Jan. 9 when a high-speed commuter ferry, the Seastreak Wall Street, slammed into a pier in lower Manhattan. The captain in that accident claimed the vessel’s controls and engines failed as he was trying to dock.

The Seastreak Wall Street, built in 2003, underwent a complete overhaul last summer, including the replacement of its engines.

While Mavedones is not familiar with the details of the accident, which the National Transportation Safety Board continues to investigate, he said maintenance alone isn’t the answer to ferry safety.

“If you maintain [the ferries] on a regular basis and practice prevention, that still doesn’t mean random issues can’t happen,” Mavodones said.

He credited Casco Bay Lines’ boat crews with reducing the chance of an accident in Portland Harbor.

Of the 26 employees who operate the ferries, six are captains, which means they hold master’s licenses from the U.S. Coast Guard. Seven deckhands also hold licenses and captain the boats in the busy summer months, and several other hands also hold licenses.

“That means more than half of our boat crews are captains. These people are highly trained and very seasoned,” said Mavodones, who was a captain for 17 years and has been with Casco Bay Lines for more than 30 years.

And unlike the captains of other small commercial craft, he said, the ferry service captains are required to have additional training in the use of marine radar under the state law that created Casco Bay Lines as a quasi-municipal island transit district in 1981.

Still, Casco Bay Lines has had its share of accidents and near-misses over the years. The most recent occurred in 2010, when a boat carrying a wedding reception ran aground on a well-known ledge near Basket Island. No one was injured in the incident.

Portland Harbor presents captains and crews with challenges, Mavodones said, including navigating among hundreds of islands, responding to fog and storms, and dealing with heavy marine traffic, especially in the summer.

The ferry service operates five vessels, which shuttle year-round between the Maine State Pier and seven harbor islands, carrying nearly 1 million passengers annually and sometimes making nearly 20 round-trips a day. A sixth boat is planned to be added soon.

Meanwhile, the Casco Bay Lines terminal is about to undergo a $3 million renovation and expansion. The transit district recently began seeking contractor proposals on the $800,000 first phase of the project.