USS Triton (SSRN-586) - Design History

Design History

Triton is considered a first-generation U.S. nuclear-powered submarine, along with Nautilus, Seawolf, Halibut, and Skate (and her sisters). While serving as fully operational units of the U.S. Navy, the vessels also played key developmental roles. Nautilus introduced the use of nuclear power for ship propulsion. Seawolf utilized a liquid-metal nuclear reactor using liquid sodium as an alternative heat exchange medium to pressurized water. Halibut was the first nuclear-powered submarine to perform a strategic nuclear deterrence patrol armed with Regulus cruise missiles. The Skates were the first nuclear-powered submarine class with more than one ship built. Triton's unique contribution to the development of nuclear power for naval propulsion was her dual reactor plant, which provided the speed required for radar picket missions.

Radar picket submarines (Navy classification "SSR") were developed during the post-war period to provide intelligence information, electronic surveillance, and fighter aircraft interception control for forward-deployed naval forces. Unlike destroyers used as radar picket ships during World War Two, these submarines could avoid attack by submerging if detected. The U.S. Navy's Migraine program involved converting existing fleet submarines into radar picket vessels, and the Navy also ordered two purpose-built diesel-electric SSRs, Sailfish and Salmon. However, these were incapable of sustaining the high submerged speeds necessary to operate with fast carrier task forces and therefore unsuitable to the task.

Nuclear power offered the only possible solution. Triton was designed in the mid-1950s as a radar picket submarine capable of operating at high speed, on the surface, in advance of an aircraft carrier task force. Triton's high speed came from her twin-reactor nuclear propulsion plant, with a designed speed, surfaced and submerged, of 28 kn (32 mph; 52 km/h). On 27 September 1959, Triton achieved "well in excess of" 30 kn (35 mph; 56 km/h) during her initial sea trials.

Triton was the only non-Soviet submarine designed with a two-reactor propulsion plant. Her S4G reactors were seagoing versions of the land-based S3G reactor prototype. Both reactors comprised the Submarine Advanced Reactor (SAR) program, a joint venture between the U.S. Navy, Atomic Energy Commission (AEC), and General Electric. As originally designed, Triton's total reactor output was rated at 34,000 horsepower (25,000 kW). However, Triton achieved 45,000 horsepower (34,000 kW) during her sea trials, and her first commanding officer, Captain Edward L. Beach, Jr., believed Triton's plant could have reached 60,000 horsepower (45,000 kW) "had that been necessary."

The number one reactor, located forward, supplied steam to the forward engineering room and the starboard propeller shaft. The number two reactor, located aft, supplied steam to the after engineering room and the port propeller shaft. Each reactor could individually supply steam for the entire ship, or the reactors could be cross-connected as required. It is this enhanced reliability, redundancy, and dependability of its dual-reactor plant that was a key factor in the selection of Triton to undertake the first submerged circumnavigation of the world.

Triton's dual-reactor plant met a number of operational and engineering objectives, specifically the high speed requirement to meet its radar picket mission, which continues to be sources of speculation and controversy to this day. During the early 1950s, many engineers at Naval Reactors branch of the U.S. Atomic Energy Commission (AEC) were concerned about depending on single-reactor plants for submarine operations, particularly involving under-the-ice Arctic missions. The presence of two de-aerating feed tanks, which are used only on surface warships, suggested that Triton's twin-reactor plant may have served as a testbed for future multi-reactor surface warships. The SAR program was the first production naval reactor developed by General Electric for the U.S. Navy, and GE used this SAR experience for the High Power Reactor (HPR) program that led to the development of the D1G and D2G naval reactors used on the Bainbridge, Truxtun, California, and Virginia classes of nuclear-powered surface ships. Finally, the U.S. Navy was debating the best approach to optimize performance, particularly underwater speed, for its nuclear submarine fleet. Triton achieved high speeds through brute horsepower, rather than the more hydrodynamically efficient teardrop-shaped hull form pioneered by Albacore which, when combined with nuclear power, allowed Skipjack to achieve higher speed with less horsepower.

To meet her radar picket role, Triton's main air search radar initially used the AN/SPS-26, the U.S. Navy's first electronically scanned, three-dimensional search radar which was laboratory tested in 1953. The first set was installed on board the destroyer leader Norfolk prior to its installation on board the Triton in 1959. Since it was scanned electronically in elevation, the AN/SPS-26 set did not need a separate height-finding radar. A submarine version of SPS-26, designated BPS-10, was under development, and it was slated for installation on the Triton. To process its radar, electronic, and air traffic data, Triton had a Combat Information Center (CIC) located in a separate air control compartment, situated between Triton's reactor and operations compartments.

Design work on a nuclear-powered radar picket submarine (SSRN) began in 1954–1955. As initially designed, it had a three-level hull, with its Combat Intelligence Center (CIC) located on the middle level. Its overall length was initially 400 feet (120 m), with a beam of 38 feet (12 m). Also as initially designed, its displacement was 4800 tons surfaced and 6500 tons submerged. January 1955 performance estimates called for the SAR propulsion plant to produce 34,000 shaft horsepower, with a surfaced speed of 27 kn (31 mph; 50 km/h)) and a submerged speed of 23 kn (26 mph; 43 km/h). Triton initially had the same dual radar system installed on the non-nuclear Sailfish-class radar picket submarines (i.e., BPS-2 search radar and BPS-3 height-finder set) housed in a large, stepped sail (see image). Construction cost was initially estimated at $78,000,000. Subsequent growth of the SAR propulsion plant necessitated the overall increase in Triton's length and tonnage, although without any loss in speed, while the installation of the AN/SPS-26 3-D search radar allowed the elimination of a separate height-finder.

Triton was to be the lead ship of a proposed class of nuclear-powered radar picket submarines. A December 1955 long-range naval planning report envisioned five carrier strike groups, each supported by two radar picket submarines. The total force included two non-nuclear Sailfish class submarines and eight nuclear submarines. With construction costs for Triton escalating, this long-range requirement was revised in 1957 to provide four nuclear-powered radar picket submarines for a single nuclear-powered carrier group, with the four remaining conventionally powered carrier groups supported by two diesel-electric radar picket submarines each.

At the time of her construction, Triton was the largest submarine ever built. Her knife-like bow, with its bulbous forefoot, provided improved surfaced sea-keeping for her radar picket role. Her surface sea-keeping was further enhanced by high reserve buoyancy (30%), provided by 22 ballast tanks, the most ever in an American submarine. She was the last submarine to have a conning tower, as well as the last American submarine to have twin screws or a stern torpedo room. Her sail was the largest ever aboard an American submarine, measuring 70 feet (21 m) long, 24 feet (7.3 m) tall, and 12 feet (3.7 m) wide, and designed to house the large AN/SPS-26 3-D air-search radar antenna when not in use. She also had a compartment solely for crew berthing, with 96 bunks, and two separate chief petty officers' (CPOs') quarters. With an overall length of 447.5 feet (136.4 m), Triton was the longest submarine ever built for the United States Navy until Ohio in 1979.