ABSTRACT
In the middle of February 1943, the situation in the North Atlantic appeared to be generally favorable for German U-boat operations as they had just scored a major victory over the Allies in the battle for Convoy SC 118. The major Allied objective was the safe and timely arrival of merchant ships, but out of the three convoys the U-boats sank eighteen ships against the loss of only three U-boats. Of great importance to both the Allies and the Germans in these three convoy battles was communications intelligence. The battles for Convoys ONS 165, ONS 167, and especially ON 166 showed that the Allies, if they were going to be the victors in the Battle of the Atlantic, had to increase the number and effectiveness of the surface and air escorts of convoys and perfect a number of techniques such as refueling at sea.
