Pearl Harbor, which exposed the weak forces in Malaya to attack. Heavy units were freed up by American reinforcements in the Atlantic. The construction programs of the late-1930s were also starting to yield new heavy units. The Mediterranean yielded far fewer reinforcements than expected due to serious losses in that theatre in 1941. The Eastern Fleet that Vice Admiral Sir James Somerville assumed command of in March 1942 was smaller than what had been envisioned in December 1941. Somerville divided the fleet into two groups, based on speed. The faster "Force A" included the aircraft carriers and , the modernized battleship (as flagship), as well as the modern cruisers and destroyers. The slower "Force B" was formed around the old carrier and four unmodernized s. A few submarines were also available. The ships had never operated together before, and both ship and air crews were deficient in training. Allied intelligence accurately assessed the strength of the Japanese force. Somerville planned to evade the Japanese during the day and close to launch torpedo strikes with radar-equipped Fairey Albacore bombers during the night. However, the plan was based on information provided by the Far East Combined Bureau (FECB), which identified only two carriers in the Japanese force. FECB also believed the Japanese would sail from Staring Bay on 21 March for a "C day" of 1 April. Thus, Somerville sailed early expecting to fight a smaller and manageable enemy force, particularly in aircraft strength. As such, Somerville likely did not see his plan as incompatible with his orders from the Admiralty, which were to protect the lines of communications in the Indian Ocean, and to maintain the Eastern Fleet as a fleet in being by avoiding unnecessary risks. The British recognized the threat of Japanese carrier-borne air attack on Ceylon after strike on Pearl Harbor, and the island's air defences were reinforced. On 7 December 1941, air defences consisted of four obsolescent three-inch anti-aircraft guns - at Trincomalee - with neither fighters nor radar. By 4 April, there were 67 Hawker Hurricanes and 44 Fairey Fulmar fighters, a radar station each at Colombo and Trincomalee, and 144 anti-aircraft guns; 37 or 38 Hurricanes were serviceable around Colombo on 5 April. The fighters were divided into three Royal Air Force (RAF) squadrons of Hawker Hurricanes (two at Colombo, and one at Trincomalee), and two squadrons of RN Fleet Air Arm (FAA) Fairey Fulmars.