Two new additions to the Steamship Authority fleet are expected to be in the water by the end of March, director of marine operations Mark Amundsen said this week.

“We are progressing for a March 29 launch, and that is a hard date with the Alabama Shipyard,” Mr. Amundsen told the Steamship Authority board of governors Tuesday morning.

The two identical boats, M/V Aquinnah and M/V Barnstable, have spent more than nine months at the shipyard in Mobile, Ala., where Mr. Amundsen has been overseeing their conversion from offshore energy tenders to Steamship Authority freight ferries that can also carry passengers and cars.

A third sister ship, M/V Monomoy, is berthed in Houma, La., awaiting its turn for conversion.

Aquinnah and Barnstable will remain quayside in Mobile for the final touches of shipyard work, Mr. Amundsen said. Their new captains and crews will then take the ferries north to New England for training and inspections before the Steamship Authority’s summer season.

The captains are already in Mobile, familiarizing themselves with the new boats, and chief engineers will soon be joining them, Mr. Amundsen said

“We’ll be going to Houma next week, to the Monomoy, just for some training,” he said.

The Steamship Authority paid almost $16 million in bond proceeds and grant funding to buy the three vessels in 2022, from a Louisiana company that had built them less than 15 years earlier to service offshore oil and gas rigs in the Gulf of Mexico. The costs of converting the boats to freight ferries, initially estimated at about $8 million apiece, skyrocketed in 2023, when only two bids came in after more than two dozen shipyards had expressed interest in doing the work.

The Steamship Authority wound up extending its timeline and negotiating with Alabama Shipyard in order to lower the conversion budget from about $20 million a boat to $27 million in total for the Aquinnah and Barnstable together, reserving the Monomoy for the time being.

Alabama Shipyard pulled the two forerunners out of the water last spring, for work that included replacing a 24-foot-long, 110-ton midsection of each boat in order to add flotation and make other changes required by U.S. Coast Guard safety regulations for carrying passengers.

At its meeting Tuesday, the Steamship Authority board approved ordering about $400,000 worth of shore-based spare parts for the new freight boats. The clutches, pumps, bearings, electrical parts and other components can be used by either the Aquinnah or the Barnstable, as well as aboard the Monomoy after its conversion.

“I absolutely love this. One order and you’re servicing three ships,” board chair Robert Jones said.