US shipbuilder Vigor Industrial has bought a new drydock for $20m.

The facility, which will be the biggest in the Puget Sound region, will be towed from South Korea in the autumn, the company said.

It will build and repair ships at its Harbor Island plant, particularly state ferries.

“The purchase of another drydock in Seattle allows Vigor to better service valued customers like Washington State Ferries, the US Coast Guard and US Navy,” said Adam Beck, Vigor executive vice president of ship repair.

“It also further strengthens our market position in commercial ship repair on the West Coast and supports our expansion into new markets.”

The dock is 640 feet long. The seller has not been named.