"Tirpitz" was repeatedly attacked by British forces. Royal Air Force (RAF) heavy bombers made four unsuccessful raids on the battleship between January and April 1942 while she was stationed at Fættenfjord. From March 1943, "Tirpitz" was based at Kaafjord in the far north of Norway. During Operation Source on 22 September 1943, she was severely damaged by explosives placed beneath her hull by Royal Navy personnel who had used midget submarines to penetrate Kaafjord. On 3 April 1944, aircraft flying from Royal Navy aircraft carriers attacked "Tirpitz" during Operation Tungsten and inflicted further damage. This attack had been timed for when it was believed repairs to rectify the damage caused by Operation Source were nearing completion. A series of subsequent aircraft carrier attacks, including Operation Mascot on 17 July and Operation Goodwood between 22 and 29 August, were unsuccessful.