USS Joy (SP-643) was a United States Navy patrol vessel in commission from 1917 to 1918.

Joy as a private yacht.
History
United States
Name	USS Joy
Namesake	Previous name retained
Builder	B. F. Wood, City Island, the Bronx, New York
Completed	1905
Acquired	June 1917
Commissioned	1917
Decommissioned	1918
Fate	Returned to owner 6 May 1919
Notes	Operated as private motor yacht Joy 1905–1917 and from 1919
General characteristics
Type	Patrol vessel
Tonnage	41 gross register tons
Length	93 ft (28 m)
Beam	11 ft (3.4 m)
Draft	4 ft (1.2 m)
Speed	23 knots
Complement	12
Armament	1 × machine gun

Joy was built as a private motor yacht of the same name by B. F. Wood at City Island in the Bronx, New York, in 1905. In June 1917, the U.S. Navy acquired her from her owners, T. M. Jones and P. C. Kauffman of Newport, Rhode Island, for use as a section patrol boat during World War I. She was commissioned as USS Joy (SP-643) in 1917.

Assigned to the 2nd Naval District in southern New England, Joy performed patrol duty until declared unfit for service sometime in 1918.

Joy was returned to Jones and Kauffman on 6 May 1919.