In 1942, the War in the Atlantic was not going well for the Allies. German submarines, operating in “wolf packs” just out of aircraft range, wrecked havoc on Allied supply lines. In the first half of the year, the Allies managed to sink just one U-boat for every forty merchant ships lost. At that rate, Britain would soon run out of matériel to sustain the war.
Lord Louis Mountbatten, as chief of Combined Operations, was responsible for coming up with a solution. He encouraged his department to explore every possibility, no matter how outlandish. One of the ideas, which originated with the inventor Geoffrey Pyke, was to built an aircraft carrier out of ice, which would allow the Allies to attack German U-boats no matter how far they sailed from the coast. The reason Pyke settled on ice was that aluminum and steel were in such short supply.
Mountbatten and Prime Minister Winston Churchill were enthusiastic.
The project was called Habakkuk. It called for the construction of wooden runways on hollowed-out icebergs, powered by motors on either side.
A small prototype was built in Canada, weighing 1,000 tons and kept frozen by a one-horsepower motor. Churchill ordered the construction of a complete ship, which the Canadians promised to deliver in 1944.
But then several problems started to add up. The expected range of the carrier was extended to 7,000 miles (11,000 kilometers). The Admiralty demanded that the ship be torpedo-proof and able to withstand the largest waves recorded. That required a thicker hull. Fleet Air decided that heavy bombers should be able to take off from the carrier, which meant the deck had to be extended.
As Habakkuk advanced, the need for it started to melt away. The Portuguese had allowed the Allies use of airfields in the Azores. A new American bomber, the B-24 Liberator, was able to close the Mid-Atlantic Gap. Longer-range fuel tanks also gave British aircraft extra patrol time over the Atlantic. The United Kingdom had broken the latest German Enigma code, which meant it knew where to find U-boats. And Mountbatten, the main backer of the project, was moved to Southeast Asia. Habakkuk was canceled in 1943.