Earlier GM boats received Model 16-248 engines, but beginning with Perch Model 16-278A engines were used. Earlier Fairbanks-Morse boats received a 9- cylinder version of the Model 38D8⅛, while boats from Sand Lance onward received 10-cylinder engines. Fairbanks-Morse supplied Model 38D8⅛ opposed piston engines, and General Motors' Cleveland Diesel division supplied Model 16-248 and 16-278A V16 engines. General Motors Model 16-248 V16 diesel engineīalao-class submarines received main engines from one of two manufacturers. There was no direct connection between the main engines and the shafts. Like their predecessors, they were true diesel-electric submarines: their four diesel engines powered electrical generators, and electric motors drove the shafts. The propulsion of the Balao-class submarines was generally similar to that of the preceding Gato-class. These mast arrangements, along with the tremendous variation in the gun layout as the war progressed account for the numerous exterior detail differences among the boats, to the point that at any given time no two Balaos looked exactly alike. Late in the war, many Balaos built with the original design had the SD air search radar moved slightly aft onto a thickened and taller mast.

About halfway through their production run, Electric Boat altered their design, moving the SJ radar mast forward of the periscopes, then altered it again a few boats later by enlarging the SD radar mast. There were minor differences in how the periscopes were braced against vibration, but both designs were nearly identical. įor the masts and periscope shears, the original arrangement for both the Government and Electric Boat designs had (forward to aft) the two tapered cone shaped periscope support shears, followed by a thin mast for the SJ surface search radar, and then by a thin mast for the SD air search radar. By the time the boats began to be launched, lessons learned from patrol reports had been worked into the design and the bridge and sail proved to be efficiently laid out, well equipped, and well liked by the crews. The Balaos incorporated the fairwater, conning tower and periscope shears reduction efforts that were being retrofitted to the Gatos and the preceding classes in the original design, refining the reductions and reducing the sail to the smallest practical size. Fortunately, in 1944 a redesigned Gould centrifugal pump replaced the noisy early-war pump, and effective diving depth was increased. Cochrane, Chief of the Bureau of Ships, to limit test depth to 400 ft (120 m). However, the limited capacity of the trim pump at deep depths, and lack of time to design a new pump, caused Rear Admiral E. A switch to a new High-Tensile Steel (HTS) alloy, combined with an increase in hull thickness from 9⁄ 16 inch (14.3 mm) to 7⁄ 8 inch (22.2 mm), would result in a test depth of 450 ft (140 m) and a collapse depth of 900 ft (270 m). In late 1941, two of the Navy's leading submarine designers, Captain Andrew McKee and Commander Armand Morgan, met to explore increasing diving depth in a redesigned Gato. The Balaos were similar to the Gatos, except they were modified to increase test depth from 300 ft (90 m) to 400 ft (120 m). Tang actually achieved a depth of 612 ft (187 m) during a test dive, Īnd exceeded that test depth when taking on water in the forward torpedo room while evading a destroyer. The most significant improvement was the use of thicker, higher yield strength steel in the pressure hull skins and frames, which increased their test depth to 400 feet (120 m). An improvement on the earlier Gato class, the boats had slight internal differences. The Balao class was a successful design of United States Navy submarine used during World War II, and with 120 boats completed, the largest class of submarines in the United States Navy. 4 × high-speed electric motors with reduction gears or 2 × low-speed electric motors ( Elliott Company or General Electric).

4 × diesel engines driving electrical generators ( Fairbanks-Morse or General Motors).

Gato class submarine