USS SC-209

History
United States Navy
Name	Submarine Chaser No. 209 (1917–1918) SC-209 (retrospectively, 1920)
Builder	Mathis Yacht Building Company, Camden, New Jersey
Laid down	1917
Commissioned	March 1918
Identification	NONM[1]
Fate	Sunk 27 August 1918
Stricken	Late 1919
Reclassified	SC-209 on 17 July 1920 (retrospectively)
General characteristics
Class and type	SC-1-class submarine chaser
Displacement	77 tons normal 85 tons full load
Length	110 ft (34 m) overall 105 ft (32 m) between perpendiculars
Beam	14 ft 9 in (4.50 m)
Draft	5 ft 7 in (1.70 m) normal 6 ft 6 in (1.98 m) full load
Propulsion	Three 220 bhp (160 kW) Standard Motor Construction Company six-cylinder gasoline engines, three shafts, 2,400 US gal (9,100 L) of gasoline; one Standard Motor Construction Company two-cylinder gasoline-powered auxiliary engine
Speed	18 knots (33 km/h; 21 mph)
Range	1,000 nmi (1,900 km; 1,200 mi) at 10 knots (19 km/h; 12 mph)
Complement	27 (2 officers, 25 enlisted men)
Sensors and processing systems	One Submarine Signal Company S.C. C Tube, M.B. Tube, or K Tube hydrophone
Armament	1 × 3-inch (76.2 mm)/23-caliber gun mount 2 × Colt .30-caliber (7.62 mm) machine guns 1 × Y-gun depth charge projector

USS SC-209, prior to July 1920, known as USS Submarine Chaser No. 209 or USS S.C. 209, was an SC-1-class submarine chaser in commission in the United States Navy during 1918. She was the victim of the deadliest friendly fire incident involving the U.S. Navy during World War I.