tanks were decreased to a capacity of 66 gallons. These were the rarest of the Mk IXs and many of them featured the "clipped" wings. The great majority of these saw postwar service with the SAAF, both in South Africa and in deployment in Korea during the 1950s. During early 1945, some Spitfire IXes and XVIes of 74 Squadron were fitted with a single RP-3 rocket under each wing. This was believed to be the only RAF Spitfire unit to use rockets operationally during the Second World War. PR Mk IX (type 374) and FR Mk IX Pending development of a dedicated Merlin 61 powered PR Spitfire (the Mk XI) at least three Mk IXs (BS338, BS339 and BS473) were taken off the production line and modified to carry two vertical cameras in the rear fuselage. The first of these was delivered to 541 Squadron at RAF Benson on 30 November 1942. Subsequently, another 15 Mk IXs were converted to PR Mk IXs (factory designation type 374) at the Vickers-Armstrong Worthy Down facility. As well as incorporating camera equipment, a wrap-around PR type windscreen was fitted and a larger oil tank was installed under the nose. All armament was removed and a PRU Blue finish applied. These aircraft lacked the "wet wing" tanks, meaning that the PR Mk IX relied on drop tanks for extra range. The most famous PR Mk IX missions involved carrying out reconnaissance missions in preparation for Operation Chastise, the 617 "Dambusters" Squadron attacks on the Ruhr dams. A PR Mk IX photographed the dams the day before the operation and photographed the Moehne Dam after the operation. FR IXs were standard, armed Mk IXs modified with a single, port-facing, oblique camera. These aircraft were used for low altitude "Dicing" missions in tactical support of army operations. 16 Squadron, which was a unit of the 2nd TAF, used several FR Mk IXs (painted a pale, "Camoutint" Pink, which provided excellent camouflage under cloud cover) to photograph the Arnhem area before and during Operation Market Garden. Another unit using FR Mk IXs was 318 (Polish) "City of Gdańsk" Fighter-Reconnaissance Squadron based in the Mediterranean. Some Spitfires in the MJ- and MK- serial ranges, sent for repair to the Forward Repair Unit (FRU), were also converted by the FRU to a different style of FR Mk IXc with streamlined blisters on both sides of the fuselage. These were