Only a major fleet could prevent a Japanese invasion of the islands. The attack on Pearl Harbor had knocked out the best part of the US Pacific Fleet. And with the sinking of the Repulse’ and ‘Prince of Wales’ all that remained to repel a Japanese invasion was a ‘Combined Striking Force’ under Dutch command.
It consisted of two heavy cruisers, seven light cruisers and twenty-two destroyers. In addition there were 25 US and 15 Dutch submarines available. Unfortunately many of the Dutch boats were obsolete and short of spares.
They would have to face an Imperial Japanese Naval Task Force detailed to guard the operations of the ‘Nanjo’ Army Group. This Task Force consisted of an aircraft carrier, two battle cruisers, twenty-two cruisers, fifty-seven destroyers and eight submarines
The single Allied superiority was in flying boats. The Dutch naval air service, (Marine Luchtvaart Dienst or MLD), had 73 modern flying boats in service, almost double the number the combined British and American navies could muster. During most of the campaigns in Malaysia, the Philippines and the East Indies, the Allied fleet units would rely on the MLD’s flying boats as their “eyes in the sky.”
Co-operation between flying boats and submarines or surface units was a type of operation the MLD had specifically trained for before the war. However, with the formation of the ABDA central command in early January, the Dutch effectively lost control of their long-range squadrons. A kind of central clearing house was set up for distribution of information gathered by the reconnaissance aircraft. The idea looked good on paper. But language, doctrine and differing command styles led to disastrous backlogs, and the Allied surface forces effectively sailed into combat blind.
Admiral Helfrich stated that, before ABDACOM, an air-to-ship message would take no more than 10 minutes to be delivered. Under the new command structure, it could take up to six hours, making the information hopelessly out of date
By February 11, the MLD had halted most offensive operations. With Japanese ground-based fighters now within range of Java, it was difficult for the Dorniers and PBYs to carry out their missions in daytime. By the end of February the surviving flying boats retreated to Australia and Ceylon.
During the culminating battles in the Java Sea on February 28 and March 1, most of the Allied ships were sunk, leaving Java naked to the invaders.