The Three Factors That Turned the Tide Totally

German U-boats took four years to build up and by early 1943 he suddenly had a large number of U-boats that could deploy. He was able to have between 36 and 40 U-boats hunting for ships at one time on any given day. The British Admiral in charge of convoy defenses talked Churchill into canceling the convoys running then from Iceland and England up to Russia in Vermont. They used up several dozen destroyers and other escorts to protect those shipments. Without air cover the U-boats were either equal or had an advantage in their tactics of stalking and closing in on convoys.