     The GATO class formed the backbone of the American submarine fleet
during the Second World War.  Seventy-three of these oceanic vessels were
built between 1940 and 1943.  They were fast, strong, well-armed, and
capable of patrolling for long periods.

     GATO class submarines bore the brunt of the undersea Pacific campaign.   
Their primary functions were to patrol enemy sea lanes, bombard enemy
islands, lay mine fields, land supplies for guerrillas and coast watchers,
and rescue downed aircraft crews.  Rescue missions were particularly hazardous
since they forced the submarine to remain vulnerable in dangerous waters 
for seemingly endless periods.   Even with these unfavorable odds, submarines
are credited with saving the lives of 280 airmen during the war.

     The armament of a GATO class submarine included 24 torpedoes, with six
torpedo tubes forward and four tubes aft.  Up to forty underwater mines 
could be carried in lieu of spare torpedoes, and these were laid through
the torpedo tubes.
      Most boats were fitted with deck gun mounts, one forward of the 
conning tower and one aft.  Often, however, only one gun was actually 
mounted.  Gun calibers varied greatly.  The first boats had 3 inch (76mm)
50-cal guns, several had 20mm 70-cal anti-aircraft guns, and toward the
end of the war some boats were fitted with 5 inch (127mm) 25 cal guns.

     GATO class submarines were built with two hulls.  The inner, or
pressure hull, contained the crew, engines, and controls.  The space
between the inner and outer hulls held the ballast tanks and fuel was open
to the circulation of the sea water.  As the fuel was used, sea water was
allowed to enter the fuel tanks to maintain a constant buoyancy. (Diesel
fuel floated on top of the water and was siphoned from the top of the
fuel tanks.)

     The size and shape of the conning tower underwent several
modifications during the course of the war.  The use of larger surface 
armament required enlargement and strengthening of the tower.
     Normally, each submarine had two periscopes, one large spotting scope
and one attack scope (slimmer and harder to detect).

     After 1942, the radar antenna was installed aft of the periscopes.
The periscope radar complex also contained the radio antenna and two crew
members' lookout stations. 

     The diesel-electric propulsion system provided power with either four
diesel engines or four electric motors coupled in pairs to drive two
propeller shafts through reduction gears.  The diesel engines also charged
the batteries, which were made up of 252 elements.






                             SPECIFICATIONS
                             
Builders:       Electric Boat, Groton
                Portsmouth Navy Yard
                Mare Island Navy Yard
                Manitowac Shipyards

Displacement:   1825 tons surfaced
                2417 tons submerged

Dimensions:     311ft 9in x 271ft 3in x 15ft 3in

Machinery:      Diesel - four General Motors or Fairbanks Morse
                Electric - four Elliot or GE

Maximum Power:  5400 hp surfaced
                2740 hp submerged

Maximum Speed:  20.25 knots surfaced
                8.75 knot submerged

Fuel Load:      378 - 472 tons

Range:          11,800 miles at 10 knots surfaced
                95 miles at 5 knots submerged
                
Torpedoes:      24 21-inch diameter

Maximum Depth:  300 ft

Complement:     65

Cost:           $6,288,200

NOTE: as of 1972, twelve GATO class submarines were still in use by the
United States Navy.  As of 1984, all diesel-powered submarines are retired.
Presently the USS Gato, a 594 class nuclear submarine is docked at the
New London Submarine Base.
