The United States Navy patrol vessel USS Halcyon, was built by the Defoe Shipbuilding Company, in Bay City, Michigan, in 1912. She was taken over by the US Navy from her owner, G. G. Barnum, at Duluth, Minnesota, on 16 June 1917. After serving briefly on section patrol in the Great Lakes, 9th Naval District, Halcyon was returned to her owner on 5 November 1917.

History
United States
Name	USS Halcyon
Builder	Defoe Shipbuilding Company
Launched	1912
Acquired	16 June 1917
Out of service	5 November 1917
Fate	Returned to owner
General characteristics
Length	40 ft (12 m)
Beam	9 ft 6 in (2.90 m)
Draft	2 ft 8 in (0.81 m)
Speed	10 kn (19 km/h)