From Bath Iron Works plans for hull no. 190.
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As the first Fletcher built at Bath Iron Works, the specifications for hull 190, Nicholas, served as the prototype for all Fletcher-class ships built there:

Length Overall: 376' 5½"
Extreme Beam: 39' 8"
Normal Displacement: 2,050 long tons
Draft: Light: 8' 1"; Mean: 13' 5" Deep: 22’8”
Designed Complement: Officers, 34; Enlisted, 295
Designed Shaft Horsepower: 60,000
Designed Speed: 36 knots
Trials Speed:: 37.1 knots
Screws: Two
Rudder: One
Stacks: Two
Tactical diameter: 950 yards at 30 knots
Endurance: 4,800 nautical miles at 15 knots.

   Initially, Nicholas, like O’Bannon and Chevalier, carried a 1.1-inch anti-aircraft cannon between the “53” and “54” 5-inch gunhouses, but this tended to overheat and jam in service. Later ships mounted a 40mm twin Bofors in this location, with which Nicholas was subsequently retrofitted. In 1944, Nicholas was further modified to carry two more of these twin mounts amidships plus two forward, below the bridge, for a total of ten barrels.
     From the beginning, the “Nick” also carried Mk 4 20mm single mounts. Although she left for the war zone without a full armament of these weapons, she picked up more en route and once may have carried as many as 13—including two on top of the pilot house—before settling on seven in 1944: four in the waist and three on the fantail.
     Thus Nicholas’ initial armament was as follows:

Primary: 5 x 5-inch/38 cal. in five single mounts
Long-range anti-aircraft: 4 x 1.1-inch cannon in one quadruple mount
Short-range anti-aircraft: 6 to 13 x 20mm Oerlikon in single mounts
Torpedo Tubes: 10 x 21-inch in two quintuple mounts
ASW: 2 racks for 600-lb. charges; 6 “K”-guns for 300-lb. charges

   Her electronics were also typical:

Radar: SC (air search) and SG (surface search serial No. 3), Mk 37 (fire control)
Sonar: QC

   From January 1944, she was modified to carry the typical 1943–1944 Fletcher-class armament:

Primary: 5 x 5-inch/38 cal. in five single mounts
Long-range anti-aircraft: 10 x 40mm Bofors in five twin mounts
Short-range anti-aircraft: 7 x 20mm Oerlikon in single mounts
Torpedo Tubes: 10 x 21-inch in two quintuple mounts
ASW: 2 racks for 600-lb. charges; 6 “K”-guns for 300-lb. charges