The Sturgeons were essentially lengthened and improved variants of the Thresher/Permit class that directly preceded them. The five-compartment arrangement of the Permits was retained, including the bow compartment, operations compartment, reactor compartment, auxiliary machinery room no. 2, and the engine room. The extra length was in the operations compartment, including longer torpedo racks to accommodate additional Mark 37 torpedoes, the most advanced in service at the time of the class's design in the late 1950s. The class was designed to SUBSAFE requirements, with seawater, main ballast, and other systems redesigned for improved safety. The biggest difference was the much larger sail, which permitted a second periscope and additional intelligence-gathering masts. The fairwater planes mounted on the sail could rotate 90 degrees, allowing the submarine to surface through thin ice. Because the S5W reactor was used, the same as in the Skipjacks and Thresher/Permits, and the displacement was increased, the Sturgeons' top speed was, 2 knots slower than the Thresher/Permits. The last nine Sturgeons were lengthened to provide more space for electronic equipment and habitability. The extra space also helped facilitate the use of dry deck shelters first deployed in 1982. The class received mid-life upgrades in the 1980s, including the BQQ-5 sonar suite with a retractable towed array, Mk 117 torpedo fire control equipment, and other electronics upgrades.
Armament
The Sturgeon-class boats were equipped to carry the Harpoon missile, the Tomahawk cruise missile, the UUM-44 SUBROC, the Mark 67 SLMM and Mark 60 CAPTOR mines, and the MK-48 and ADCAP torpedoes. Torpedo tubes were located amidships to accommodate the bow-mounted sonar. The bow covering the sonar sphere was made from steel or glass reinforced plastic, both varieties having been produced both booted and not booted. Booted domes are covered with a half-inch layer of rubber. The GRP domes improved the bow sonar sphere performance; though for intelligence gathering missions, the towed-array sonar was normally used as it was a much more sensitive array.
Noise reduction
Several Sturgeon boats and related submarines were modifications of the original designs to test ways to reduce noise.
, a one-ship class, was completed with an S5G reactor which was cooled using natural convection rather than pumps at lower power levels and then pumps when higher power levels were required and did not have reduction gears, but utilized a sophisticated multi-stage direct drive turbine in an attempt to reduce the noise signature from the reduction gears. The turbine arrangement was not considered successful because of its complex warm-up and cooldown procedures.
, also a one-ship class, was completed using a turbo-electric system for main propulsion rather than direct drive from the steam turbines. The massive motor and associated generators required her to be lengthened to. The Lipscomb’s trial of turbo-electric propulsion was not considered successful due to lack of reliability and she was decommissioned in 1989.
was outfitted with Raytheon Harmonic Power Conditioners which eliminated an electrical bus noise problem that was inherent in the class. This was done by harmonic conditioning of the power system. This successful feature was later outfitted on the entire class.
was outfitted with SHT during a non-refueling overhaul, which reduced noise and the submarine sonar profile.
Variants
Beginning with, units of this class had a longer hull, giving them more living and working space than previous submarines. received an additional hull extension containing cable tapping equipment that brought her total length to. A number of the long hull Sturgeon-class SSNs, including Parche, L. Mendel Rivers, and Richard B. Russell were involved in top-secret reconnaissance missions, including cable tap operations in the Barents and Okhotsk seas. Parche received nine Presidential Unit Citations for successful missions. A total of seven boats were modified to carry the SEALDry Deck Shelter. The DDS is a submersible launch hangar with a lockout chamber attached to the ship's midships weapons shipping hatch, facilitating the use of SEAL Delivery Vehicles. DDS-equipped boats were tasked with the covert insertion of special forces.
