Editing C and D-class destroyer (section)

===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/>