Trincomalee and Batticaloa, Sri Lanka
On 9 April, the Japanese attacked the harbor at Trincomalee at 07:00. The British again had warning of the attack, and the carrier Hermes and her escorts had left the night before. They were returning to port when they were discovered at 08:55. Hermes had no aircraft on board, and so was defenceless when 70 bombers attacked her at 10:35 off Batticaloa. Hit 40 times, Hermes sank with the loss of 307 men. The destroyer HMAS Vampire and the corvette HMS Hollyhock were also sunk.
The hospital ship Vita later picked up 590 survivors. The RAF lost at least eight Hawker Hurricanes and the Fleet Air Arm one Fairey Fulmar. The Japanese lost five bombers and six fighters, one in a suicide attack on the Trincomalee fuel tanks.
During the day, nine of the Royal Air Force’s No. 11 Squadron Bristol Blenheim bombers made the first ever Allied air attack against Nagumo's Carrier Force. Bombing from 11,000 ft (3300 m) they scored no hits while losing five of their number to the Striking Force's Combat Air Patrol A6M2 Zeroes, four over the IJN Carriers and one due to an encounter with IJN aircraft returning from the Hermes raid, but in return shot down one Zero.
Read more about this topic: Indian Ocean Raid