KINGSTON — Port of Kingston commissioners voted Wednesday to buy a used 149-seat ferry to begin a passenger service to Seattle this fall.

The port is buying the 72-foot ferry Spirit from Four Seasons Marine Services of Silverdale for $2.5 million. The sale will be finalized after the Spirit is surveyed in Port Townsend this week.

“This is a pretty exciting time for the Port of Kingston,” Commissioner Pete DeBoer said.

The purchase agreement was approved by DeBoer and Tom Coultas. Commissioner Marc Bissonnette was absent.

The port will use money from a $3.5 million Federal Transit Administration grant to buy the boat. DeBoer said port staff looked at about 12 vessels before deciding on Spirit. The port decided not to pursue building a new boat in December because construction would take longer than the grant guidelines would allow.

Spirit is a catamaran built by All American Marine of Bellingham in 2004. The boat is powered by four, 740 horsepower diesel engines and a water jet drive. It burns about 80 gallons of fuel per hour, said Loren Gerhard, Four Seasons vice president of marine operations.

Four Seasons has used Spirit as a tour boat in Alaska and will use it again this summer, before it is delivered to Kingston. That will save the port operating money, DeBoer said.

The port hopes to launch the passenger service in October. Before then it will be adding to its roster of prospective riders, finishing work on the landing dock in Kingston and seeking federal grants to help with operating costs.

Planning is being overseen by Eric Osnes, who was recently hired to manage the passenger ferry project.

Greater Kingston Chamber of Commerce President Dan Martin said the ferry purchase will bring Kingston closer to a long-sought goal. A passenger service from Kingston to Seattle faltered and folded after a brief run in 2005.

“I think this is a historic event for Kingston,” Martin said. “This is going to be a big, dramatic change that the town of Kingston has been looking for for 15 years.”