PORTLAND — The newest vessel in Casco Bay Lines’ fleet of island passenger ferries arrived in Portland Harbor early Thursday morning.

The Wabanaki, a 399-passenger ferry, departed Wednesday afternoon from the Rhode Island shipyard where it was built and headed into the harbor shortly after sunrise Thursday.

Blount Boats Inc., of Warren, R.I., received a contract from the Maine Department of Transportation to build the ferry, which will replace the 40-year-old Island Romance.

The cost of building the new ferry was $4.5 million, and was funded with federal stimulus money from the American Recovery and Reinvestment Act. Construction started in April 2012.

Over the past 57 years, Blount Boats has built nine vessels for Casco Bay Lines, also known as the Casco Bay Island Transit District.

The ferries, which depart from Casco Bay Lines ferry terminal on Portland’s waterfront, are used year-round to transport island residents, tourists, cars and freight from the mainland to communities on Peaks, Great Diamond, Little Diamond, Cliff, Long and Chebeague islands. The ferry service also offers sunset tours of the bay, moonlight cruises, a mailboat run and a cruise to Bailey Island.

The Wabanaki is the first new ferry to join Casco Bay Lines since 2005, when the Aucocisco III was put into service. Casco Bay Lines transports about one million passengers a year.

“We are very pleased to get it,” said Nicholas Mavodones Jr., Casco Bay Lines’ operations manager. “I think the islanders will really like it.”

Mavodones said the Wabanaki has been equipped with a modern heating system, freight storage areas that are separate from passenger seating areas, more comfortable seats, more nooks and crannies for passengers to sit in, and tables for passengers to sit at. It will also be equipped with an elevator.

The Wabanaki is not designed to carry vehicles.

“The boat looks and runs great. People are going to love it,” said Gene Willard, a senior captain with Casco Bay Lines, by phone from the ferry Wednesday.

Willard said the new boat resembles, at least from a distance, the Aucocisco III.

Willard accompanied Mavodones to Rhode Island for the vessel’s maiden voyage to Portland. It left Rhode Island around 3 p.m.

Bob Pelletier, Blount Boat’s vice president, was also aboard the ferry Wednesday night.

Pelletier said the Wabanaki was being captained Wednesday night by John Mederious, who also captained the Island Romance when it made its maiden voyage to Portland in 1973.

“He (Mederious) has delivered boats all over the world for me,” Pelletier said.

Mavodones said the Island Romance is worn out and needs to be replaced.

The boat, which has a seating capacity of 297 passengers, will be retired this year and will likely be sold to a private owner.

The 110-foot-long Wabanaki could be ready to join the Casco Bay Lines fleet of passenger ferries by the end of January, Mavodones said.

Staff Writer Dennis Hoey can be contacted at 791-6365 or at:[email protected]