USS Arctic (SP-1158) was a wooden-hulled steam tug acquired by the US Navy during World War I. Arctic was briefly employed as a convoy escort during the war and later used to tow targets and transport ammunition. She was returned to commercial service in 1919. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
Mean Of Transportation