SSN 637 Sturgeon Class

Displacement: Surfaced 4,250 t, except SSN 678-687 4,460 t, Submerged 4,780 t, except SSN 678-687 4,960 t
Dimensions: Length 89 m, except 92 m SSN 678-687; Beam 10 m; Draft 9 m.
Armament: four 533mm amidships torpedo tubes,
Propulsion: One S5W nuclear reactor, two steam turbines, 15,000 shp, one shaft, 25kts.
Description: Sturgeon class submarines were built for anti-submarine warfare in the late 1960s and 1970s. Using the same propulsion system as their smaller predecessors of the SSN-585 Skipjack and SSN-594 Permit classes, the larger Sturgeons sacrificed speed for greater combat capabilities. A total of six Sturgeon-class boats were modified to carry the SEAL Dry Deck Shelter [DDS], one in 1982 and five between 1988 and 1991. They are SSN 678-680, 682, 684, 686 are listed as "DDS Capable" -- either permanently fitted with the DDS or trained with them. In this configuration they are primarily tasked with the covert insertion of Special Forces troops from an attached Dry Deck Shelter (DDS). The Dry Deck Shelter is a submersible launch hanger with a hyperbolic chamber that attaches to the ship's Weapon Shipping Hatch. The DDS provides the most tactically practical means of SEAL delivery due to its size, capabilities, and location on the ship.

USS Parche had an extended hull and was used for highly classified covert operations.

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