C and D Class Destroyer - Design and Description

Design and Description

These ships were based on the preceding B class, but were enlarged to increase their endurance and to allow for the inclusion of a QF 3-inch 20 cwt anti-aircraft gun. This class introduced a director control tower for British destroyers. The 'C' class were unique in having a split bridge, with the compass platform and wheelhouse separated from the chartroom and director tower. This unusual layout was not repeated. As per Admiralty policy in alternating Two-Speed Destroyer Sweep (TSDS) minesweeping gear and ASDIC (sonar) capability between destroyer flotillas, the C class lacked ASDIC and were designed to carry only six depth charges. The D class were repeats of the C's, except that the TSDS was replaced by storage for up to 30 depth charges and ASDIC.

The C and D class destroyers displaced 1,375 long tons (1,397 t) at standard load and 1,865 long tons (1,895 t) at deep load. The ships 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). They were 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 that operated at a pressure of 300 psi (2,068 kPa; 21 kgf/cm2) and a temperature of 600 °F (316 °C). The destroyers carried a maximum of 473 long tons (481 t) of fuel oil that gave them a range of 5,500 nautical miles (10,200 km; 6,300 mi) at 15 knots (28 km/h; 17 mph). Their complement was 145 officers and men.

Kempenfelt, leader of the C class, displaced 15 long tons (15 t) more than her destroyers and carried an extra 30 personnel who formed the staff of the Captain (D), commanding officer of the flotilla. Unique among the C and D-class ships, she had three Yarrow water-tube boilers that operated at a pressure of 310 psi (2,137 kPa; 22 kgf/cm2). Duncan, leader of the 'D' class, displaced 25 long tons (25 t) more than her destroyers and also carried an extra 30 personnel.

All of the ships of the class 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, they had a single QF 3-inch 20 cwt AA gun between her funnels. The C-class ships carried two 40-millimetre (1.6 in) QF 2-pounder Mk II AA guns mounted on the aft end of their forecastle deck. The D-class destroyers had been intended to carry the new QF 0.5-inch Vickers Mk III machine gun in quadruple mountings on the bridge wings, but these were not initially available, so the old 2-pounder guns were retained in Daring, Diana, Diamond and Defender. The 3-inch AA gun was removed in 1936–37, and the 2-pounders were relocated between the funnels on platforms.

The main guns were controlled by an Admiralty Fire Control Clock Mk I that used data derived from the director and the rangefinder. They had no capability for anti-aircraft fire and the anti-aircraft guns were aimed solely by eye.

When purchased by Canada in 1937–38, the four C-class destroyers were refitted to meet Canadian specifications, including the installation of Type 124 ASDIC. It is not clear how much Kempenfelt had been modified when she was turned over in October 1939, other than steam heating had yet been fitted.