Sailfish Class (Fast Attack Diesel Submarines)
To the MIGRAINE units of the SSR-481 Requin and SSR-267 Pompon classes were added two new-construction boats, USS Sailfish (SSR-572) and USS Salmon (SSR-573), designed from the keel up as radar pickets.
With a length of 350 feet and a surface displacement of over 2,300 tons, these were among the largest conventional submarines ever built by the United States. These were forty feet longer and displaced 600 tons more than their World War II predecessors, though shared their hull form and 400-foot test depth. Because it was assumed that they would spend most of their time on the surface, Sailfish and Salmon were given substantial reserve buoyancy and hull forms optimized for surface performance. The four aft torpedo tubes were not included in this design.
On each, the BPS-2 air-search radars could be rotated into a fore-and-aft position for retraction into the large sail fairwater, but just as in the MIGRAINE III boats, the BPS-3 height finder was mounted on a pedestal abaft the sail. The two new SSRs were both commissioned in mid-1956, giving a total of 12 radar pickets, but since the earliest of the MIGRAINE boats were reaching the end of their service lives, that total would soon drop.
Eventually, seven SSRs (Requin, Tigrone, Burrfish, Pompon, Ray, Redfin, and Sailfish) were assigned to the Atlantic Fleet and operated nominally in the Caribbean and North Atlantic, with regular participation in NATO exercises and periodic deployments to the Mediterranean as part of the U.S. 6th Fleet. The five remaining (Spinax, Rasher, Raton, Rock, and Salmon) went to the Pacific Fleet and operated off western North America and in WESTPAC deployments to 7th Fleet. Although the SSRs became key participants in fleet air defense as early-warning pickets and CAP controllers 50 to 100 nautical miles in front of typical Cold War carrier battlegroups, their overall effectiveness was frequently hampered by their relatively modest surface speeds, particularly when task-group course changes required rapid repositioning. Even Sailfish and Salmon, the fastest of the type, could only make 20 knots on the surface, little better than the older fleet boats. Thus, the accelerating development of submarine nuclear power - and the debut of USS Nautilus (SSN-571) in early 1955 - appeared to offer a welcome solution to this operational problem.
2,030 long tons (2,063 t) light
2,334 long tons (2,371 t) surfaced
3,168 long tons (3,219 t) submerged
Length: 350 ft (110 m)
Beam: 29 ft 1 in. (8.86 m)
Draft: 16 ft 4 in (5 m)
20.5 kt (38.0 km/h; 23.6 mph) surfaced,
Diesel Electric 2 screws
6 × 21 in (533 mm) torpedo tubes