SS-169 V-7 Dolphin

V-7 was approved in the FY1930 building program. She was a scout cruiser submarine, originally given the designation SF-10, then SC-3. During construction, she was renamed Dolphin in February 1931 and designated SS-169 in July 1931. She commissioned in June 1932.

The penultimate design in the V-boat series was laid down at Portsmouth in June 1930 and emerged as USS Dolphin (formerly V-7, SS-169) two years later. With a length of 319 feet and a displacement only a little more than half that of her three predecessors, Dolphin was clearly an attempt to strike a happy medium between those latter ships and earlier S-class submarines, which were little more than large coastal boats.

The general arrangement of propulsion machinery was identical to that of V-5 and V-6, but even with a surface displacement of only 1,718 tons, Dolphin's scaled-down main engines - 1,750 horsepower each - could only just deliver the surface speed of the larger ships, and her endurance and torpedo load-out were much reduced. Interestingly, however, Dolphin's size and weight were very nearly ideal for the range and duration of the war-patrols that became customary in the Pacific during World War Two, and indeed, the war-time Gato (SS-212), Balao (SS-285), and Tench (SS-417) classes had similar dimensions.

Early in the war, Dolphin herself made three patrols from Pearl Harbor without notable distinction, and her deteriorating material condition soon led to restricting her to training duties - first in Hawaii, and then in New London for the duration of the war. She was decommissioned in October 1945 and sold for scrapping a year later.