his bombers to attack at mast-height, increasing accuracy but making them easier targets for Italian anti-aircraft defences. Losses averaged 12% during this time. 38 Squadron, 40 Squadron and 104 Squadron, equipped with Wellington bombers, hit Axis convoys in Tripoli. In concert with Royal Navy submarines, the RAF and FAA sank 108 Axis ships (300,000 grt) between June and September. In September, 33% of the 96,000 tons of supplies dispatched were lost to British submarine and air attack. Part of the reason for this favourable outcome in November 1941, was the arrival of Force K of the Royal Navy, which during the Battle of the Duisburg Convoy sank all the ships, which practically blockaded Libyan ports. Soon after, Force K was reinforced by the arrival in Malta of Force B with the light cruisers and and the K-class destroyers, Kimberley and Kingston, on 27 November. Joint operations with the RAF were so effective that during November 1941, Axis fuel losses amounted to 49,365 tons out of 79,208 tons. Among the contributors to the sinking of Axis shipping was 828 Naval Air Squadron, 830 Naval Air Squadron, the British 10th Naval Flotilla and 69 Squadron which shadowed convoys with their Maryland aircraft. Special flights of RAF Wellingtons fitted with air-to-surface vessel (ASV) radar, were important to Force K operations, and Ultra intelligence reached Malta on Axis convoy movements. The RAF Malta Command would then dispatch the ASV-Wellingtons to sweep the seas and direct the British naval forces to the convoy. On 13 November, the carrier HMS Ark Royal— returning to Gibraltar after transporting aircraft to Malta—was sunk by a U-boat. Twelve days later, the battleship was sunk by a U-boat, followed by the light cruiser on 15 December. On 19 December, ships from both forces ran into a minefield while pursuing an Italian convoy. Damage from the mines sank the cruiser and damaged the cruiser . The destroyer was also mined while attempting to assist Neptune. Kandahar was scuttled the next day by the destroyer . Following the disaster and with a resurgence of the Axis aerial bombardment of Malta, surface ships were withdrawn from the central Mediterranean in January 1942. While Italian bombing was again proving successful against the British, the Luftwaffe returned in force in December 1941 to renew intensive bombing. The Kriegsmarine sent nearly half of all the German U-boats on operations in the Atlantic Ocean to the Mediterranean