From construction to combat: general characteristics and service history of the R-Class Submarines in the U.S. Navy

The US Navy built R-class submarines rapidly between 1918 and 1945, and they were essential to naval strategy. Despite being finished after World War I, their initial engagement was restricted by the Armistice and logistical difficulties.

Between 1918 and 1945, the R-class submarines were a major part of the submarine fleet of the U.S. Navy. This course was quickly constructed when America entered World War I. The R-15 through R-20 were finished in July and October of 1918. However, since most of the class was completed after the Armistice, these submarines did not see overseas action.

The pressing need for naval capabilities during a conflict led to the rapid construction of the R-class submarines. The submarines were not directly involved in the war effort at that point, despite having been completed in the last months of World War I due to logistical issues and the Armistice. In the years that followed, the R-class submarines were more widely deployed and saw active action, which contributed to the changing naval tactics and difficulties that arose between the interwar years and World War II.

General Characteristics:

The R-class submarines built by the United States were a class of naval craft that fell into two separate categories. The first group’s surface displacement was 569 long tonnes (578 t), while its submerged displacement was 680 long tonnes (691 t). On the other hand, the second group showed comparatively smaller displacement numbers, with 510 long tonnes (518 t) on the surface and 583 long tonnes (592 t) submerged. Additionally, the measurements differed: the first group was 186 ft 2 in (56.74 m) long, 18 ft 1 in (5.51 m) wide, and 14 ft 5 in (4.39 m) deep. The second group was 175 ft (53 m) long, 16 ft 8 in (5.08 m) wide, and 13 ft 11 in (4.24 m) deep.

Two × 600 hp (447 kW) NELSECO diesel engines, two × 467 hp (348 kW) electric motors from Electro Dynamic Co., two × 60-cell batteries, and two × shafts were used for propulsion in the first group. The second group’s components included two × 500 hp (373 kW) Busch-Sulzer diesel engines, two × 400 hp (298 kW) Diehl electric motors, two × 60-cell batteries, and two × shafts. Various powertrain changes led to varying speeds. The first group reached 13.5 knots (25.0 km/h; 15.5 mph) when surfaced and 10 knots (19 km/h; 12 mph) while submerged. The second group reached 14 knots (26 km/h; 16 mph) when surfaced and 11 knots (20 km/h; 13 mph) when submerged. A 200-foot test depth was assigned to each group.

With a capacity of thirty commanders and men, each group had four × torpedo tubes—eight torpedoes each, measuring twenty-one inches (533 mm) for the first group and eight hundred millimetres (450 mm) for the second. The 3-inch (76 mm)/50 calibre deck gun fitted to each submarine improved its offensive power.

Service History:

Significant operational and service history was experienced by the Group 1 boats, often known as the AA-1 class submarines. They were originally decommissioned later that same year in 1931, having crossed the Panama Canal as a group of 20 on January 18, 1931. These submarines were recommissioned in 1940, however, and they continued to operate in a variety of capacities. They conducted patrols between Submarine Base New London, Connecticut, and Bermuda; they also cruised the Caribbean and were used as sonar targets near Key West, Florida.

At least two R-boats made unsuccessful efforts to engage German U-boats with torpedoes while on their Bermuda patrols. Interestingly, three of these class’s submarines (R-3, R-17, and R-19) were transferred to the Royal Navy of the United Kingdom in 1941–1942, when they were given the new names HMS P.511, HMS P.512, and HMS P.514. Unfortunately, on June 21, 1942, HMS P.514 was lost in a collision with the Canadian minesweeper HMCS Georgian, which was wrongly reported as a U-boat.

On June 12, 1943, a catastrophe off the coast of Key West claimed the life of R-12, another AA-1-class submarine. To improve their ability to rescue people in the case of sinking, the submarines received modifications in between the wars. Among these changes was the installation of a motor room hatch, the motor room being the compartment after the other. Consequently, the tapered after casing turned into a step.

One R-class submarine was possibly seen for a brief period in the 1943 film “Crash Dive,” which was filmed at the New London submarine facility, demonstrating the AA-1 class submarines’ influence on popular culture.

In addition to the US Navy, Electric Boat built four R-class vessels (R-1 to R-4) for the Peruvian Navy. Constructed after World War I with components from abandoned S-class submarines, they were later renamed Islay, Casma, Pacocha, and Arica in 1957 after undergoing renovations in 1935–1936 and 1955–1956, respectively. In 1960, these Peruvian submarines were finally disposed of.

In December 2020, the wreckage of an AA-1-class submarine, R-8, was discovered off the shore of Ocean City, Maryland. After being used as a target by bombers, the ship sank in 1936.