The repair, maintenance and conversion of the Navy's ships was of equal, if not greater importance, particularly during wartime.
An idea of the scale of this work can be gained from the Second World War, when Chatham refitted 1,360 ships, including the cruiser HMS Ajax on her return from the Battle of the River Plate and Lord Mountbatten's destroyer HMS Kelly. By this time the workforce had increased to over 17,000 people, including a large number of women workers brought in to fill gaps left by men serving with the armed forces.
During the 1950's modernisation and conversion work was equally important for the yard with major programmes to stretch and improve ‘T' class submarines, and modernise destroyers, such as HMS Carron (sister ship to Cavalier). The lead boat of the ‘O' class submarine programme, HM Submarine Oberon was launched from the Dockyard in 1959 heralding the last burst of ship building in the yard.
1962 saw the launch of HM Submarine Ocelot (see top right photograph of the HM Submarine Ocelot in No.3 Dry Dock), the last warship to built for the Royal Navy at Chatham and although the launch, in 1966, of HMCS Okanagan marked the end of warship construction at the dockyard, it was kept busy with repair, maintenance and refit work on minesweepers and frigates. In 1970, a purpose built nuclear submarine refitting complex located to the south of No 1 Basin in the Steam Yard was also opened.
