Editing I-class destroyer (section)

===Wartime modifications===
Early war modifications involved replacing the after bank of torpedoes with a [[12-pounder gun|QF 12-pounder]] (3 inch/76&nbsp;mm) [[anti-aircraft warfare|anti-aircraft]] (AA) gun, cutting down the after funnel and mainmast to improve its field of fire and adding a pair of [[Oerlikon 20 mm cannon|QF 20 mm Oerlikon]] guns in the bridge wings. Radar Type 286, a metric wavelength surface-warning set, was added as it became available and the ineffective multiple {{convert|0.5|in|mm|abbr=on}} [[Vickers machine gun]]s were replaced with Oerlikons; the central tube was deleted from the torpedo launchers to lessen topweight. ''Icarus'' lost 'Y' gun to stow extra depth charges (for a total load of 110) and their mortars. Surviving ships received a third pair of Oerlikons, added abreast the searchlight position and the 12-pounder was deleted to increase depth charge stowage. In some ships, 'A' gun was replaced with a [[Hedgehog (weapon)|Hedgehog]] forward-throwing A/S weapon but this alteration seems to have been reversed at a later stage. ''Ilex'', ''Intrepid'', ''Impulsive'' and ''Isis'' had 'B' gun removed and two [[QF 6 pounder 10 cwt gun|QF 6-pounder]] 10 cwt (2.25 inch/57&nbsp;mm L/47) guns were added on the twin mounting Mark I* along with a Hedgehog, the former for anti-[[E boat]] work.

''Inglefield'' later had the second bank of torpedo tubes re-instated but like her sisters, the central tube was removed. A {{convert|4|in|mm|abbr=on}} AA gun was added instead of 'X' gun and she had six Oerlikons. Type 291 radar was later added at the foremast head as well as [[Huff-Duff]] in some ships.

The ex-Turkish ships were modified along similar lines to their I-class sisters. ''Inconstant'' later received Type 270 radar, a centimetric wavelength target-indication set, in place of the director and rangefinder on the bridge. Again, eventually, six Oerlikons were carried.