USS Marpessa (SP-787) was a 50 foot (15.24 m) "express yacht" that became a United States Navy section patrol vessel in commission from 1917 to 1919 retaining the civilian name.

[1][2][4] Matheson had an estate at Coconut Grove, Florida and entered Marpessa, powered by two six cylinder 175 horsepower Van Blercks gasoline engines, in racing events, particularly the annual Miami regattas in January involving power boats brought from the north as well as boats based in the Miami area.

[1][2][5][6] The boat was badly damaged when a hired captain, over the owner's objection, held course after finding himself inside the buoy and struck a reef off Matinicock point near Oyster Bay.

[6] On 18 August 1917, the U.S. Navy acquired her from her owner for use as a section patrol boat during World War I.

She was enrolled in the Naval Coast Defense Reserve on 8 September 1917 and commissioned as USS Marpessa (SP-787) on 1 October 1917.