United States R-class submarine

Tied up along the dock from right to left: R-12 (SS-89), R-15 (SS-92), R-13 (SS-90) with R-9 (SS-86) and an unidentified R-boat probably in Pearl Harbor, c. mid-1920s.
Class overview
Name	R class
Builders	Bethlehem Quincy (R-1 to R-14)[1] Bethlehem San Francisco (R-15 to R-20)[2] Lake Torpedo Boat Co. (R-21 to R-27) Electric Boat Co. (Four boats for Peru)
Operators	United States Navy  Peruvian Navy  Royal Navy
Preceded by	O class
Succeeded by	S class
Built	1917–1919
In commission	1918–1931, 1940–1945
Completed	27
Lost	2
Retired	25
General characteristics
Type	Submarine
Displacement	Electric Boat design: 574 long tons (583 t) surfaced 685 long tons (696 t) submerged Lake Torpedo Boat Co. design: 497 long tons (505 t) surfaced 652 long tons (662 t) submerged
Length	Electric Boat design: 186 ft 3 in (56.77 m) Lake Torpedo Boat Co. design: 175 ft (53 m)
Beam	Electric Boat design: 18 ft 0 in (5.49 m) Lake Torpedo Boat Co. design: 16 ft 7 in (5.05 m)
Draft	Electric Boat design: 14 ft 5 in (4.39 m) Lake Torpedo Boat Co. design: 13 ft 11 in (4.24 m)
Propulsion	Electric Boat design: 2 × 600 hp (447 kW) NELSECO 6-EB-14 diesel engines 2 × 467 hp (348 kW) Electro Dynamic Co. electric motors 2 × 60-cell batteries 2 × shafts Lake Torpedo Boat Co. design: 2 × 500 hp (373 kW) Busch-Sulzer diesel engines 2 × 400 hp (298 kW) Diehl electric motors 1 × 120-cell batteries 2 × shafts
Speed	Electric Boat design: 12.5 knots (23.2 km/h; 14.4 mph) surfaced 9.3 knots (17.2 km/h; 10.7 mph) submerged Lake Torpedo Boat Co. design: 14 knots (26 km/h; 16 mph) surfaced 11.4 knots (21.1 km/h; 13.1 mph) submerged
Test depth	200 ft (61 m)
Complement	30 officers and men
Armament	Both designs: 4 × 21-inch (533 mm) torpedo tubes, 8 torpedoes 1 × 3 inch (76 mm)/50 caliber deck gun[3]

The R-class submarines were a class of United States Navy coastal-defense submarines active from 1918 until 1945. With the first of the class laid down following the American entry into World War I, they were built rapidly. Although R-15 through R-20 were completed July–October 1918, they did not serve overseas, and the bulk of the class were not completed until after the Armistice. As had been the usual practice in several of the preceding classes, design and construction of the 27 boats of this class was split between the Electric Boat Company and the Lake Torpedo Boat Company. Both designs were built to the same military operational specifications, but differed considerably in design and detail specifics.^[4]