SSR-267 Pompon

By the time the Cold War with the Soviet Union was in full swing, air defense of U.S. carrier battle groups on potential strike missions near the Russian landmass generated a requirement for even more submarine radar pickets. Eventually, six more World War II submarines - all Manitowac-built USS Gato (SS-212)-class boats - were chosen for the more drastic MIGRAINE III SSR conversion.

Because experience had shown that even the newer SSR configurations were seriously cramped, the final MIGRAINE design called for cutting the boats in two and inserting a 24-foot "plug" to get additional room for an expanded CIC and electronic spaces forward of the main control room. Even so, the MIGRAINE IIIs also had to sacrifice their after torpedo tubes for more berthing space, but they were fitted with a larger, streamlined sail, with the BPS-2 search radar mounted aft of the periscopes and other masts. An AN/BPS-3 height-finder radar on a pedestal just behind the sail and an AN/URN-3 TACAN beacon on the afterdeck completed the installation.

The six MIGRAINE III boats - USSs Pompon (SSR-267), Rasher (SSR-269), Raton (SSR-270), Ray (SSR-271), Redfin (SSR-272), and Rock (SSR-274) - were all converted at the Philadelphia Navy Yard between 1951 and 1953 - giving the Navy a total of ten radar picket submarines to face the growing Soviet threat just as the Korean War was drawing to a close.

Although two of the MIGRAINE III boats were put out of service and scrapped almost immediately, the remainder were reclassified as conventional attack boats (SS) or as auxiliary general submarines (AGSS) for non-combat duties, and they survived for "twilight careers" that lasted as late as 1978. The longest-lived was Sailfish, which was decommissioned in September of that year and which still remains laid up and afloat at Bremerton. Several of the others served as Naval Reserve training hulks after decommission, and five were eventually sunk as targets, most recently Salmon in 1993. Tigrone was re-commissioned in March 1962 and, as an AGSS, played a major part in developmental testing for several passive sonar systems before she was finally put out of service in 1975. Similarly, Redfin - as AGSS-272 - became a test platform for the pioneering inertial navigation systems required by the Polaris SLBM program. She was then decommissioned in May 1967 and scrapped four years later. Burrfish had an interesting aftermath: The Canadian Navy leased the boat in 1961, renamed her HMCS Grilse (SS-71), and used her as a "live" target for anti-submarine warfare training. She was returned to the U.S. Navy in 1969 and sunk as a target that same year.