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.