Seneca as a civilian yacht, sometime prior to her U.S. Navy service.
History
United States
Name	USS Seneca (1917-1918) USS SP-427 (1918-1919)
Namesake	Seneca was her previous name retained SP-427 was her section patrol number
Completed	1888
Acquired	7 May 1917
Commissioned	18 July 1917
Decommissioned	2 January 1919
Stricken	6 January 1919
Fate	Returned to owner 6 January 1919
Notes	Operated as civilian yacht Seneca until 1917 and from 1919
General characteristics
Type	Minesweeper and patrol vessel
Tonnage	157 gross register tons
Length	150 ft (46 m)
Beam	20 ft (6.1 m)
Draft	10 ft 6 in (3.20 m)
Propulsion	Steam engine
Speed	18 knots
Complement	33
Armament	2 × 6-pounder guns

The third USS Seneca (SP-427), later USS SP-427, was a United States Navy minesweeper and patrol vessel in commission from 1917 to 1919.

Seneca was built as a civilian steam yacht in 1888 at Boston, Massachusetts. On 7 May 1917, the U.S. Navy acquired her from her owner, the Johnson Lighterage Company, for use as a minesweeper and patrol vessel on the section patrol during World War I. She was commissioned as USS Seneca (SP-427) on 17 July 1917.

Based at Tompkinsville, Staten Island, New York, Seneca carried out minesweeping and patrol duties for the rest of World War I. In 1918, she was renamed USS SP-427.

SP-427 was decommissioned on 2 January 1919. She was stricken from the Navy List on 6 January 1919 and returned to Johnson Lighterage the same day.

Seneca (SP-427) should not be confused the barge USS Seneca (SP-1240), which was in commission at the same time.

•  This article incorporates text from the public domain Dictionary of American Naval Fighting Ships. The entry can be found here.
• Department of the Navy Naval History and Heritage Command Online Library of Selected Images: Civilian Ships: Seneca (Steam Yacht, 1888). Served as USS Seneca (SP-427) and USS SP-427 in 1917-1919
• NavSource Online: Section Patrol Craft Photo Archive: SP-427 ex-Seneca (SP 427)