Please answer the following question: Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. USS Charles Mann (SP-522) - USS Charles Mann (SP-522) was a United States Navy tug and patrol vessel in commission from 1917 to 1919.Charles Mann was built as a commercial tug of the same name in 1903 at South Portland Maine. The U.S. Navy purchased her on 6 or 7 June 1917 for use as a tug and section patrol vessel during World War I. She was commissioned as USS Charles Mann (SP-522) on 7 June 1917 with Chief Boatswain's Mate A.
A:
Mean Of Transportation