In early 1942, Britain was in a desperate situation.

The Royal Air Force had fought off Germany’s relentless onslaught in the Battle of Britain and much of the German army was fighting the Soviets in Eastern Europe, but the British remained isolated and at risk of being cut off from the world.

Hitler’s U-boats were wreaking havoc on Britain’s vital supply lines, and although the U.S. had entered the war on the side of the Allies, effective large-scale anti-submarine weapons and tactics were not yet fully developed or deployed.

Short of ships, material, and manpower, Prime Minister Winston Churchill turned to an audacious effort to combat the Kriegsmarine’s submarine wolfpacks: The Royal Navy would build a massive aircraft carrier out of ice and sail it to the middle of the Atlantic.

Known as Project Habbakuk, the outlandish plan would have resulted in the largest warship in history providing a large and nearly constant Allied air presence over the most vulnerable part of its supply network.

A Desperate Situation

World War II British convoy
A British convoy steams to port in England, September 3, 1940. (AP Photo)

Allied losses to the German U-boat menace were hard to understate. U-boats had sunk nearly 300 ships carrying over 1 million tons of cargo between July and October 1940, a period known as the “First Happy Time” to German submariners.

It was followed by the “Second Happy Time” between January and August 1942, which saw the Germans begin attacking American vessels. An additional 600 ships and 3 million tons of cargo were lost, as were the lives of over 5,000 sailors and passengers.

Particularly troublesome was a 300-mile stretch of ocean known as the mid-Atlantic gap. The area was too far for land-based aircraft from either side of the Atlantic to operate in. As casualties mounted, sailors began referring to this area as the “Black Pit.”