Tugboat operator Foss Maritime provides harbor and marine transportation services on both the West Coast and East Coast of the US. It operates more than 90 tugs and 95 barges, including the world's first hybrid tug -- the Green Assist. Besides towing, the company offers logistics, ship assist, and shipyard services. It operates from four main facilities in the west, located in Long Beach, California; Portland, Oregon; San Francisco; and Seattle; plus one in Boston, operated by subsidiary Constellation Maritime. Foss Maritime is owned by Saltchuk Resources, which controls a mix of air cargo, marine services, and marine transportation businesses, including Totem Ocean Trailer Express and Sea Star Line.