Project Habbakuk – The unsinkable aircraft carrier built from ice

The Project Habbakuk aircraft carrier was one of the most unusual, and bizarre military projects ever conceived.

During the height of the second world war, Great Britain was slowly being choked of supplies by the relentless attacks of German U-Boats on Atlantic convoys bringing much-needed supplies to the island. Aircraft could provide some cover for the ships at either end of the journey, but due to their limited range, in the middle of the atlantic ocean, all they had for protection were a limited number of naval escort vessels.

Geoffrey Pyke was a mentally unstable Cambridge undergraduate who also happened to be a genius. He had strange mannerisms, and even stranger ideas on how the war could be won. From his hospital bed in a psychiatric ward he came up with the idea of a gigantic aircraft carrierĀ made from ice which could provide air cover for the vulnerable convoys in the middle of the north Atlantic.

Pyke got his idea after reading and article in the National Geographic about icebergs and their immense strength. He sent his idea to Lord Louis Mountbatten, the head of Combined Operations. Mountbatten was impressed with Pyke’s unusual thinking and brought him onboard (figuratively speaking) to investigate the idea further.

Habakkuk aircraft carrier made from Ice (Pykrete)

Initially the idea was dubbed ‘Berg-ships’, and both Pyke and Mountbatten envisaged a whole fleet of supersized carriers which would be almost impervious to enemy fire, and could be repaired at sea by just adding more ice.

From the start it was clear regular ice wouldn’t work. It melted too quickly and was too heavy, meaning that only a small percentage was above the waterline. The invention of Pykrete changed all that. It was a simple mix of woodpulp and water, which when frozen was lighter, stronger and slower melting than plain ice. Pykrete could be machined or cast into shape easily, and was incredibly cheap to manufacture.

Habakkuk aircraft carrier made from Ice (Pykrete)

The plan was for a vessel nearly 2,000 ft long, 300 ft wide and 200 ft tall. It would have weighed over 2 million tons, and its hull would have been over 40 ft thick. An onboard cooling system would keep the hull frozen via a series of cooling ducts running through the ice. Inside it would have a huge hangar space and living quarters for the ship’s compliment of 3590 sailors and airmen. Power would come from 26 propellers mounted in nacelles attached to the side of the ship.

A large-scale model of the ship, now codenamed Habbakuk (or Habakkuk), was commissioned to study the effect of explosive damage on the hull, while a smaller prototype was to be built for testing of the cooling system. Work began early in 1943 at Jasper National Park in Canada. The Canadian builders said it would take just 8 men two weeks to build the smaller 60 ft long prototype. And that a full-size vessel could be built by 1944.

This timescale proved to be hopelessly optimistic. And in fact issues with the ice melting and the ship slowly bending meant that steel had to be introduced to the design, causing the costs to more than treble. By the summer of 1943, problems and issues regarding the construction of the Habbakuk aircraft carrier had started to mount up, added to that the Admiralty started to lose interest in the design for numerous reasons, including; spiraling build costs, permission from Portugal to use airfields in the Azores (in the mid-Atlantic) for hunting U-Boats, longer range aerial escorts, and the fact better interception and de-coding of U-Boat communications meant bombers and naval vessels knew where to find the enemy submarines. There simply wasn’t a need for a giant aircraft carrier anymore.

In December 1943 the Habbakuk project was cancelled. Interestingly, the it took three years for the prototype in Canada to melt away!

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