United States R-class submarine

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For other ship classes of the same name, see British R class submarine and Italian R class submarine.
R-class submarines
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
Builders: Fore River Shipyard (R-1 to R-14)
Union Iron Works (R-15 to R-20)
Lake Torpedo Boat (R-21 to R-27)
Electric Boat (4 boats for Peru)
Operators:  United States Navy
 Peruvian Navy
 Royal Navy
Preceded by: O-class submarine
Succeeded by: S-class submarine
Built: 1917-1919
In commission: 1918-1931, 1940-1945
Completed: 27
Lost: 2
Retired: 25
General characteristics
Type: Submarine
Displacement: Group 1:
569 long tons (578 t) surfaced
680 long tons (691 t) submerged
Group 2:
510 long tons (518 t) surfaced
583 long tons (592 t) submerged
Length: Group 1: 186 ft 2 in (56.74 m)
Group 2: 175 ft (53 m)
Beam: Group 1: 18 ft 1 in (5.51 m)
Group 2: 16 ft 8 in (5.08 m)
Draft: Group 1: 14 ft 5 in (4.39 m)
Group 2: 13 ft 11 in (4.24 m)


Group 1:
2 × 600 hp (447 kW) NELSECO diesel engines
2 × 467 hp (348 kW) Electro Dynamic Co. electric motors
2 x 60-cell batteries
2 x shafts
Group 2:
2 × 500 hp (373 kW) Busch-Sulzer diesel engines
2 × 400 hp (298 kW) Diehl Manufacture Co. electric motors
2 x 60-cell batteries
2 x shafts
Speed: Group 1:
13.5 knots (25.0 km/h; 15.5 mph) surfaced
10 knots (19 km/h; 12 mph) submerged
Group 2:
14 knots (26 km/h; 16 mph) surfaced
11 knots (20 km/h; 13 mph) submerged
Test depth: 200 ft (61 m)
Complement: 30 officers and men
Armament: Group 1:
4 × 21 inch (533 mm) torpedo tubes, 8 torpedoes
1 × 3 inch (76 mm)/50 caliber deck gun
Group 2:
4 × 18 inch (457 mm) torpedo tubes, 8 torpedoes
1 × 3 inch (76 mm)/50 caliber deck gun

The R-class submarines were a class of United States Navy 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, but none were completed until after the Armistice.


Group 1
The R-1 thru R-20 boats, designed by Electric Boat and built by Fore River Shipyard and Union Iron Works, were known as the "R-1 class" submarines . These single-hull boats were structurally very similar to the preceding O-class, but larger and therefore with more powerful machinery to maintain the required speed. For the first time in a US submarine class, 21-inch (533 mm) torpedo tubes were fitted, a tube diameter that is still standard worldwide. A more powerful fixed 3 inch (76 mm)/50 caliber deck gun replaced the retractable 3"/23 caliber gun found on previous classes.[1]
Group 2
R-21 to R-27, which were slightly smaller and faster than the R-1s, were designed and built by Lake Torpedo Boat Co. and are sometimes regarded as a separate class, the "R-21 class." Compared with the Lake-designed O-class group, these featured a double hull and had their diving planes more conventionally positioned fore and aft, but retained the Lake O-class' characteristic wide stern and 18-inch (457 mm) torpedo tubes. They were equipped with the same 3"/50 deck gun as the Group 1 boats. Their smaller size compared with Group 1 allowed Lake to repeat the machinery of their O-class boats, which probably resulted in cost savings. Some Group 2 boats were fitted with a bow fairing to improve reserve buoyancy. This probably housed expanded ballast tanks. Unlike the Group 1 boats, most of which survived to serve in World War II, the Group 2 boats were scrapped in 1930. The Lake company's demise in 1924 and the obsolescent 18-inch torpedo armament probably contributed to this.[2][3]


The Group 1 boats were decommissioned in 1931, but were recommissioned in 1940 to serve as training boats at Submarine Base New London, Connecticut. Three (R-3, R-17, and R-19) were transferred to the United Kingdom's Royal Navy as HMS P.511, HMS P.512, and HMS P.514 in 1941-1942. P.514 was lost on 21 June 1942 in a collision with the Canadian minesweeper HMCS Georgian due to being mistaken for a U-boat. R-12 was lost on 12 June 1943 in an accident off Key West, Florida.

At some point between the wars the US R-class were modified for improved rescue ability in the event of sinking. A motor room hatch was added, the motor room being the aftermost compartment. The tapered after casing became a step as a result of this modification.[4]

At least one R-class submarine can be seen briefly in the 1943 movie Crash Dive, filmed at the New London submarine base.

Electric Boat built four "R Class" boats for the Peruvian Navy (R-1 to R-4). Built after World War I using materials assembled from cancelled S-class submarines, they were refitted in 1935–36 and 1955–56, and renamed Islay, Casma, Pacocha, and Arica in 1957. They were discarded in 1960.


Group 1 (Electric Boat design)

Group 2 (Lake Torpedo Boat Company design)


  1. ^ Gardiner, p. 130
  2. ^ Gardiner, p. 130
  3. ^ Pigboats.com R-boats page
  4. ^ Pigboats.com R-boats page

This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.

See also[edit]

Media related to R class submarines of the United States at Wikimedia Commons