A foundering marina/condominium project in Newcastle has been re-floated by Hallowell developer Kevin Mattson, an avid boater and champion of reviving downtown communities.

He expects the bulk of construction to be completed this summer.

The 19th-century style building will provide four luxury apartments upstairs, and a first-floor commercial space, in keeping with the character of downtown Newcastle, a Damariscotta River town where shipyards once flourished and many elegant homes remain.

Mattson said he waited until legal challenges from a neighbor had been cleared up before purchasing the stalled project, which for months involved a cement elevator shaft, a pier built without proper permits and an owner unable to complete construction.

Mattson said it’s challenging to develop the property in a slumped economy, which he describes as “a total implosion of the housing market and total implosion of the credit market.” But he is gambling that there will be people willing to spend upwards of $500,000 for a custom condo with a boat slip and basement parking garage.

The site provides dramatic views downriver, plus 22 boat slips, a ramp and floats on a stone pier. Mattson owns the nearby brick Newcastle Square building and is a co-owner of the Newcastle Publick House in that historic structure. “I really like Newcastle,” said Mattson, who owns a home in South Bristol and said he enjoys traveling downriver in his boat.

Mattson, of Hallowell, has been involved in numerous projects, including renovating old mills in Saco. His father founded a central Maine construction company in the 1950s, and Mattson got his start in buying and renovating old buildings with a credit card good for $10,000.

He said he is investing about $5 million in the Newcastle condo/marina project. The architect is Tor Glendinning of Newcastle.