HMS Duncan (D99) - Design and Construction

Design and Construction

Duncan displaced 1,400 long tons (1,400 t) at standard load. The ship had an overall length of 329 feet (100.3 m), a beam of 33 feet (10.1 m) and a draught of 12 feet 6 inches (3.8 m). She was powered by Parsons geared steam turbines, driving two shafts, which developed a total of 36,000 shaft horsepower (27,000 kW) and gave a maximum speed of 36 knots (67 km/h; 41 mph). Steam for the turbines was provided by three Admiralty 3-drum water-tube boilers. Duncan carried a maximum of 390 long tons (400 t) of fuel oil that gave her a range of 5,870 nautical miles (10,870 km; 6,760 mi) at 15 knots (28 km/h; 17 mph). The ship's complement was 175 officers and men.

The ship mounted four 45-calibre 4.7-inch Mk IX guns in single mounts designated 'A', 'B', 'X' and 'Y' from front to rear. For anti-aircraft (AA) defence, Duncan had a single 12-pounder AA gun between her funnels and two quadruple Mark I mounts for the QF 0.5-inch Vickers Mark III machine guns mounted on the sides of her bridge. She was fitted with two above-water quadruple torpedo tube mounts for 21-inch torpedoes. One depth charge rail and two throwers were fitted; 20 depth charges were originally carried, but this increased to 35 shortly after the war began. In 1936, the 12-pounder was replaced by two QF 2-pounder Mk II AA guns. Sometime after the Dunkirk evacuation, the ship's rear torpedo tube mount was removed and replaced by a 12-pounder AA gun and the quadruple 0.5-inch machine guns were replaced by 20-millimetre (0.79 in) Oerlikon AA guns.

Duncan was ordered under the 1930 Naval Estimates on 2 February 1931 from Portsmouth Dockyard. She was laid down on 25 September 1931, launched on 7 July 1932 and finally commissioned into the Navy on 31 March 1933. Built as a flotilla leader, she displaced 25 long tons more than the rest of her class and carried an extra 30 personnel. These personnel formed the staff of the Captain (D) of the flotilla.