The summer crowds and seasonal yachts have left Menemsha and were replaced this week by a 55-by-185-foot barge and crane for construction of the new U.S. Coast Guard boathouse.

The large barge arrived Tuesday night in Menemsha harbor, tugged in by the Jaguar of New Bedford and the Patrick J. Hunt of Narragansett, R.I.

“It’s finally here, which is a great thing,” said Lou Vinciguerra, project manager for the Coast Guard boathouse.

Construction on the new 5,000-square-foot single-bay boathouse begins on Friday with the building of a temporary structure for the crane, Mr. Vinciguerra said. Driving test piles for the foundation and installation of sheet piles and construction of the bulkhead will follow. A floating dock will also be installed.

The barge and crane will remain in the harbor for several months, Mr. Vinciguerra said. Construction is expected to be completed by next summer.

The new boathouse replaces the historic red and white building that was destroyed in a July 2010 fire. The cause of the fire was never determined. Congress has approved $10 million for the new building, which includes a boat ramp, locker rooms and storage. The design also calls for the traditional white siding and red roof.

Large materials for the building will arrive by barge during the winter months; interior fixtures and poured concrete will arrive via road.

Mortensen Construction of Minneapolis, Minn. is the contractor on the project. RDA Construction of Canton will do some of the initial work in the harbor including installation of pilings for the building and pouring the concrete slab. Commercial and recreational boat slips will remain accessible during the process.