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SSN-597 Tulibee

In 1956 Admiral Arleigh Burke, then CNO, requested that the Committee on Undersea Warfare of the National Academy of Sciences study the effect of advanced technology on submarine warfare. The result of this study, dubbed "Project Nobska" was an increased emphasis on deeper-diving, ultraquiet designs utilizing long-range sonar. The USS Tullibee incorporated three design changes based on Project Nobska. First, it incorporated the first bow-mounted spherical sonar array. This required the second innovation, amidships, angled torpedo tubes. Thirdly, Tullibee was propelled by a very quiet turboelectric power plant.

Naval Reactors' effort to develop a quiet nuclear propulsion plant began early — even before the sea trials of the Nautilus — with the hunter-killer submarine Tullibee (SSN 597). The purpose of the hunter-killer was to ambush enemy submarines. As the mission of the ship was seen in the early 1950s, speed was less important than silence. By substituting an electric-drive system for reduction gears, Rickover hoped to reduce noise. In this approach a generator ran an electric motor. Varying the speed of the motor would achieve the same result as the reduction gear, but there would be a penalty; the electric propulsion system would be larger and heavier than the components it replaced.

On 20 October 1954, the Department of Defense requested the Atomic Energy Commission to develop a small reactor for a small hunter-killer submarine. The ship was meant to be the first of a large class. The commission, wishing to broaden industrial participation in the program, assigned the project to Combustion Engineering, Incorporated. The S1C prototype achieved full power operation on 19 December 1959 at Windsor, Connecticut. Congress authorized the Tullibee in the 1958 shipbuilding program, Electric Boat launched the ship on 27 April 1960, and the navy commissioned her on November 9 of that year. The ship was not small; although her tonnage, beam, and draft were less than the Skipjack, her length was greater. By the time the Tullibee was in operation, she was about to be superseded by the Thresher class.

Tullibee combined the ASW focus of the SSKs with the smallest nuclear reactor then feasible with an eye toward a relatively cheap, dedicated ASW asset that could be deployed in the numbers still considered necessary to fully populate the forward barriers. Compared to the 15,000 SHP S5W type reactor of a Skipjack, Tullibee had a 2500 SHP reactor and turbo-electric drive. She could barely make 20 knots, but she lacked the reduction gears whose loud tonals made prior SSNs so easy for SOSUS to detect at extreme range. She also continued the tradition established by the BQR-4 equipped SSKs by mounting a large, bow mounted, passive, low frequency array, the BQR-7. On Tullibee, the BQR-7 was wrapped around the first spherical active sonar, the BQS-6, and together they formed the first integrated sonar system, the BQQ-1.

Superficially, the Tullibee appeared to be one of the blind alleys into which technological evolution occasionally wandered. Nevertheless, the ship was important. To get good reception, her sonar was placed far forward, as far away from the ship's self-generated noise as possible. Her torpedo tubes were moved aft into the midship section and were angled outward from the centerline—features that were incorporated in the Thresher submarines.8 Finally, electric drive worked well; the submarine was the quietest nuclear platform the Navy had.

As an ASW platform her performance was unmatched, but almost as soon as the decision to deploy Tullibee was made, a further decision was made to avoid specialized platforms and pursue instead a multipurpose SSN that best combined the speed of Skipjack and the ASW capability of Tullibee into one platform. This became the USS Thresher.



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