USS Grackle (AM-73) was a minesweeper in the service of the United States Navy during World War II.Grackle was laid down on 6 June 1929 as MV Notre Dame by the Bath Iron Works Corp. of Bath Maine for F. J. O'Hara and Sons Inc. of Boston Massachusetts. She was launched on 2 December 1929 delivered on 21 December 1929 and renamed Grackle on 14 August 1940. Acquired by the Navy on 16 September 1940 her conversion to a minesweeper began on 1 October 1940 at the Bethlehem Steel Co. 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