Underwater Propulsion Power Program
Guppy II Program
The GUPPY II conversion (SCB 47), implemented from 1947 to 1951, was generally similar to the GUPPY I, except for retention of both periscopes and introduction of the recently perfected snorkel. The addition of three new masts; snorkel induction, snorkel exhaust, and ESM mast -- required more room in the upper portion of the sail. BuShips approved two different sail designs:
1) The "Electric Boat Sail" had a straight trailing edge, round windows, a wider top and a more rounded forward edge.
2) The " Portsmouth Sail" had a thinner top, curved trailing edge, square windows and a sharper lower forward edge. It was put on all boats, which used the government plans for the conversion.
Some boats with a Portsmouth Sail had an SV radar and needed extra room to house the aerial, thus had a bulge at the sail top. Later modifications put the SS or SS2 radars on these and other boats which had a smaller aerial and had an indicator with interlocks which allowed the mast to be housed only with the aerial in certain angular positions. Also, some GUPPY II and GUPPY III boats had their sails extended higher above the waterline, the "Northern Sail", to raise the bridge, allowing it to be manned in more severe weather.
All boats converted during the GUPPY II program that originally had high-speed drive motors with reduction gears had these replaced with low-speed direct-drive motors, producing 2500 horsepower (1.9 MW) per shaft.
The two GUPPY I boats, Odax and Pomodon, were modified to GUPPY II standard.
USS Cochino (SS-345) (Balao)
USS Tiru (SS-416) (Balao)
307' 7" length
6 x 21” TT Bow