Balao class submarine

The Balao class was a successful design of United States Navy submarine used during World War II, and at 128 copies built, the largest class of submarines in the United States Navy. An improvement on the earlier Gato class, the boats had slight internal differences. The most significant improvement was the use of higher yield steel in the pressure hull, which increased their test depth to .

Propulsion

The propulsion of the Balao class submarines was generally similar to that of the preceding Gato class. Like their predecessors, they were true diesel-electric submarines: their four diesel engines powered electrical generators, and electric motors drove the shafts. There was no direct connection between the diesel engines and the shafts.

Balao class submarines received diesel engines from one of two manufacturers. Fairbanks-Morse supplied Model 38D8-⅛ opposed piston engines, and General Motors' Electro-Motive Diesel division supplied Model 16 V16 engines. Earlier Fairbanks-Morse boats received a 9-cylinder version of the Model 38D8-⅛, while boats from onward received 10-cylinder engines. Earlier GM boats received Model 16-248 engines, but beginning with Model 16-278A engines were used. In each case, the newer engines had greater displacement than the old, but were rated at the same power; they operated at lower mean effective pressure for greater reliability.

Two submarines, and , were to receive Hooven-Owens-Rentschler (H.O.R.) diesels, but both boats were cancelled.

Two manufacturers supplied electric motors for the Balao class. Elliott Company motors were fitted primarily to boats with Fairbanks-Morse engines. General Electric motors were fitted primarily to boats with General Motors engines, but some Fairbanks-Morse boats received GE motors. Allis-Chalmers motors were to be used in SS-530 through SS-536, but those seven boats were cancelled before even receiving names.

Earlier submarines carried four high-speed electric motors (two per shaft), which had to be fitted with reduction gears to slow their outputs down to an appropriate speed for the shafts. This reduction gearing was very noisy, and made the submarine easier to detect with hydrophones. A handful of late Balao class submarines received low-speed double armature motors which drove the shafts directly and were much quieter, but this improvement was not universally fitted until the succeeding Tench class.

As the diesel engines were not directly connected to the shafts, the electric motors had to drive the shafts all the time. On the surface, with all diesel generators in operation, the full electric plant was used to produce 5,400 shp. However, due to limited battery capacity, only half of the electric plant was used underwater: one motor per shaft on four-motor boats, and one armature per motor on two-motor boats.

The Balao class was successful, and one of its class brought down what remains to this date the largest ship sunk by a submarine, the super-carrier Japanese aircraft carrier Shinano.

Museums

Eight Balao-class submarines are open to public viewing. They primarily depend on revenue generated by visitors to keep them operational and up to U.S. Navy standards - each boat gets a yearly inspection and a "report card". Some boats, like the USS Batfish (SS-310), encourage youth functions and allow a group of volunteers to sleep overnight in the crew's quarters. The following is a complete list of Balao-class museum boats:

• at War Memorial Park in Muskogee, Oklahoma
• at Independence Seaport Museum in Philadelphia, Pennsylvania
• at USS Bowfin Sea Museum and Park in Honolulu, Hawaii
• at Patriot's Point in Mount Pleasant, South Carolina
• at New Jersey Naval Museum in Hackensack, New Jersey
• at Battleship Cove in Fall River, Massachusetts
• at San Francisco Maritime National Historical Park in San Francisco, California
• at Arkansas Inland Maritime Museum in North Little Rock, Arkansas

References