Cascade General officially took control yesterday of the 57-acre Swan Island Shipyard, for which it has been the sole contractor since 1995.

The facility, acquired from the Port of Portland for $30.8 million, was the last publicly owned commercial yard in the country. It was not a profitable operation for the port, but it was a profitable sale.

The port has owned the shipyard since 1953. The sale come with $18 million up front, which the port will use to pay off a 25-year-old Port improvement bond, eliminating the possibility of future property tax assessments.

The original deal between the port and Cascade was for $38.8 million and 90 acres that included 32 acres of undeveloped land along the Willamette River side of Swan Island. The final deal did not include the excess land.

Cammell Laird Holdings, Britain’s largest ship building, provided financing for the acquisition. As a result, it owns a share of the company, Portland Ship Yard LLC, which was set up as an affiliate of Cascade general to own and operate the yard.