1942 In February and March, after the ABDA fleet composed of American, British, Dutch and Australian warships was destroyed, the Royal Navy's East India Fleet (also known as the Eastern Fleet) became the biggest threat to Japan's expansion in Southeast Asia. In order to destroy this seemingly powerful fleet and provide support for the ongoing Myanmar campaign. Nan Yunzhong led six aircraft carriers, namely Chicheng, Longxiang, Longfei, Black Dragon, Xianghe and Ruihe, to raid the allied targets in the Indian Ocean.
In addition to replacing the Kaga, which is under maintenance, this mobile unit contains almost all the essence of the Japanese aircraft carrier force. Six aircraft carriers carry about 350 carrier-based aircraft. In addition, Nanyun has 4 battleships, 7 cruisers, 19 destroyers and 5 submarines. It is not difficult to see the Japanese determination to fight from the size of the fleet.
The situation of the Royal Navy's East India Fleet is also not optimistic. Among the fleet, only four R-class battleships, battle cruiser Prestige, small carrier SportsGod and seven old cruisers with a service life of at least ten years are worth mentioning. James somerville (then commander of the Eastern Fleet) had only two chips: two new fleet carriers, the Unyielding and the Mighty. The total number of carrier aircraft owned by the East India Fleet is only about 100, among which there are many old models such as swordfish. In addition, the biggest problem facing the fleet is the lack of auxiliary ships such as oil tankers and quartermaster ships, which leads to the fleet relying too much on ports for replenishment.
To make matters worse, the political situation in Ceylon is also very chaotic, and many local residents even have the illusion of letting the Japanese liberate themselves from British rule.
The Japanese first took action against ships in the Bay of Bengal. Under the leadership of Kenzaburo Ozawa, Dragon Boat and six other cruisers sank 23 ships, and more than five were sunk by Japanese submarines on the west coast of India.