USS Tiru Guppy Submarine

Tiru was completed as a Guppy II in 1948, then refitted as a Guppy III in 1959. She remained in service until 1975.

Guppy (greater underwater propulsive power), a U.S. Navy program to upgrade the underwater speed and endurance of existing boats, was stimulated by studies of captured German Type XXI submarines. The program included three major phases. Guppy I, essentially experimental, involved only two boats. They both became part of the main program, Guppy II, which converted 24 boats during the late 1940s and early 1950s. The key features were extensive streamlining, more batteries, and a snorkel air-breathing system. Beginning in 1959, nine of the Guppy IIs underwent refitting as Guppy IIIs with lengthened hulls to accommodate new sonar and electronics.

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