Editing C and D-class destroyer (section)

==Design and description==
These ships were based on the preceding [[B-class destroyer|B class]], but were enlarged to increase their endurance and to allow for the inclusion of a [[QF 3-inch 20 cwt]] [[Anti-aircraft warfare|anti-aircraft gun]].<ref name=l4/> This class introduced a [[Fire-control system|director-control tower]] for British destroyers. The 'C' class were unique in having a split [[bridge (nautical)|bridge]], with the compass platform and [[Pilothouse|wheelhouse]] separated from the chartroom and director tower. This unusual layout was not repeated. As per [[British Admiralty|Admiralty]] policy in alternating Two-Speed Destroyer Sweep (TSDS) [[minesweeper (ship)|minesweeping gear]] and [[Sonar#History|ASDIC]] (sonar) capability between destroyer flotillas, the C class lacked ASDIC and were designed to carry only six [[depth charge]]s. 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.<ref>Friedman, pp. 205–215, 298–299</ref>

The C- and D-class destroyers displaced {{convert|1375|LT|t}} at [[Displacement (ship)|standard]] load and {{convert|1865|LT|t}} at [[deep load]]. The ships had an [[length overall|overall length]] of {{convert|329|ft|m|1}}, a [[beam (nautical)|beam]] of {{convert|33|ft|m|1}} and a [[draft (hull)|draught]] of {{convert|12|ft|6|in|m|1}}. They were powered by [[Parsons Marine Steam Turbine Company|Parsons]] geared [[steam turbine]]s, driving two shafts, which developed a total of {{convert|36000|shp|lk=in}} and gave a maximum speed of {{convert|36|kn|lk=in}}.<ref>Whitley, pp. 26, 102</ref> Steam for the turbines was provided by three Admiralty 3-drum [[water-tube boiler]]s that operated at a pressure of {{convert|300|psi|kPa kg/cm2|0|abbr=on|lk=on}} and a temperature of {{convert|600|°F}}. The destroyers carried a maximum of {{convert|473|LT|t}} of [[fuel oil]] that gave them a range of {{convert|5500|nmi|lk=in}} at {{convert|15|kn}}. Their complement was 145 officers and [[naval rating|ratings]].<ref name=l4>Lenton, p. 154</ref>

{{HMS|Kempenfelt|I18|2}}, leader of the C class, displaced {{convert|15|LT|t}} more than her destroyers and carried an extra 30 personnel who formed the staff of the [[Captain (D)]], commanding officer of the flotilla.<ref name=w7>Whitley, p. 27</ref> Unique among the C and D-class ships, she had three [[Yarrow Shipbuilders|Yarrow]] [[water-tube boiler]]s that operated at a pressure of {{convert|310|psi|kPa kg/cm2|0|abbr=on}}.<ref name=l4/> {{HMS|Duncan|D99|2}}, leader of the 'D' class, displaced {{convert|25|LT|t}} more than her destroyers and also carried an extra 30 personnel.<ref>Whitley, p. 101</ref>

All of the ships of the class mounted four 45-[[caliber (artillery)|calibre]] [[QF 4.7-inch Mk IX & XII naval gun|4.7-inch Mk IX guns]] in single mounts, designated 'A', 'B', 'X', and 'Y' from front to rear. For [[Anti-aircraft warfare|anti-aircraft]] (AA) defence, they had a single [[QF 3-inch 20 cwt]]<ref group=Note>"cwt" is the abbreviation for [[hundredweight]], 30 cwt referring to the weight of the gun.</ref> AA gun between her [[funnel (ship)|funnel]]s. The C-class ships carried two {{convert|40|mm|adj=on|1}} [[QF 2 pounder naval gun|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 [[Vickers .50 machine gun|QF 0.5-inch (12.7&nbsp;mm) 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 ships were fitted with two above-water quadruple mount for [[British 21-inch torpedo|{{convert|21|in|adj=on|0}}]] torpedoes.<ref>Lenton, pp. 154–55</ref>

The main guns were controlled by an [[Admiralty Fire Control Clock]] Mk I that used data derived from the director and the [[Rangefinding telemeter|rangefinder]]. They had no capability for anti-aircraft fire and the anti-aircraft guns were aimed solely by eye.<ref>Hodges and Friedman, pp. 12, 17</ref>

When purchased by Canada in 1937–38, the four C-class destroyers were refitted to meet Canadian specifications,<ref>Douglas, p. 52</ref> including the installation of [[List of British Asdic systems|Type 124]] [[ASDIC]].<ref>Brown, p. 164</ref> 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.<ref>Douglas, p. 65</ref>

===Wartime modifications===
Beginning in May 1940, the after bank of torpedo tubes was removed and replaced with a [[QF 12 pounder 12 cwt naval gun|QF 12-pounder Mk V anti-aircraft gun]], the after mast and funnel being cut down to improve the gun's field of fire. Four to six [[Oerlikon 20 mm cannon|QF 20&nbsp;mm Oerlikon]] [[Autocannon|cannon]]s were added to the surviving ships, usually replacing the 2-pounder or .50-calibre machine gun mounts between the funnels. One pair of these was added to the bridge wings and the other pair was mounted on the [[searchlight]] platform.<ref name=l6/> Early in the war, depth charge stowage increased to 33 in the C class, while the D class carried 38.<ref>Friedman, pp. 236–37</ref> 'Y' gun on the [[Deck (ship)|quarterdeck]] was removed on many ships to allow for additional depth charge stowage as was the 12-pounder. On at least one ship, this latter gun replaced 'X' gun. Most ships had either 'A' or 'B' gun replaced by a [[Hedgehog (weapon)|Hedgehog]] anti-submarine [[spigot mortar]], although ''Duncan'' retained both and received a split Hedgehog that was mounted on either side of 'A' gun. Some ships that received the Hedgehog in 'B' position also mounted two old [[QF 6 pounder Hotchkiss|QF 6-pounder]] [[Hotchkiss gun]]s for use against U-boats at very close range.<ref name=l6>Lenton, pp. 154–56</ref>

Most ships had their [[List of British ordnance terms#DCT|director-control tower]] and [[Rangefinding telemeter|rangefinder]] above the [[bridge (nautical)|bridge]] removed in exchange for a [[Type 271 radar|Type 271]] target-indication [[radar]]. A [[Type 286 radar|Type 286]] short-range surface search radar, adapted from the [[Royal Air Force]]'s ASV radar, was also added. The early models, however, could only scan directly forward and had to be aimed by turning the entire ship. Some ships also received a [[Huff-Duff]] [[radio direction finder]] on a short [[mainmast]].<ref name=l6/>