Death of the Wolfpacks
This is the VHS release (see more).
SummaryFrom the distributor: "It was the longest single battle of World War II. For nearly six years, Allied supply ships and their armed escorts conducted a deadly cat-and-mouse game with Nazi submarines, which lurked beneath the waters, poised to sever the vital lifeline that kept England in the conflict.
DEATH OF THE WOLFPACKS chronicles this long battle, from the early days when the U-boats enjoyed virtually unchallenged dominance of the North Atlantic to the final movement of the war, when Admiral Doenitz's once-vaunted wolfpacks were being sunk at a nearly 60% rate. Military historians detail the pivotal events in the long fight, including the entry of the United States into the war, the capture of an "Enigma" code machine and Hitler's refusal to provide his admiral with the vessels he needed to continue fighting effectively.
This is the authoritative examination of the battle that Winston Churchill called the dominating factor throughout the entire course of the war in Europe."