The Habakkuk or Habbakuk project (spelling variant) was a project initiated by Great Britain during the Second World War which involved the construction of an aircraft carrier made of pykrete (a composite material consisting of cellulose and ice), to be used against U-boats Germans in the middle of the Atlantic, in an area that was outside the range of ground-based aircraft.
Geoffrey Pyke was an old friend of the British scientist J.D. Bernal and had been recommended to Lord Mountbatten, Chief of Combined Operations, by Cabinet Minister Leo Amery. Pyke had worked at Combined Operations Headquarters (COHQ) alongside Bernal and was regarded as a genius by Mountbatten. Pyke conceived the idea of Habbakuk while in the United States and was organizing the production of the M29 Weasels for the Plow project, a scheme to assemble an elite unit for winter operations in Norway, Romania and the Italian Alps. The problem was that aluminum and steel were in short supply and were in demand for other applications. Pyke realized that the answer was ice, which could be made with the 1% energy needed for the equivalent mass of steel. He proposed that an iceberg, whether natural or man-made, be leveled to provide a runway and shaped to house aircraft. From New York in December 1942, Pyke sent the proposal in a diplomatic bag to COHQ, with a label prohibiting anyone other than Mountbatten from opening the package. Mountbatten in turn passed Pyke's proposal to Winston Churchill, who was initially thrilled. Pyke was not the first to suggest a floating stopping point for aircraft, nor the first to suggest that such a floating island could have been built in ice. In fact, a German scientist, Dr. Arthur Gerke, had proposed the idea and carried out some preliminary experiments at Lake Zurich in 1930. The idea was so recurrent that in 1940 the idea of an ice island was widespread. throughout the Admiralty, but it was treated as a joke by officials, including Nevil Shute, who released a memorandum in which he collected the increasingly sarcastic comments. The document should have been retrieved shortly before it reached the First Sea Lord's mailbox.The vessel was to be 610m (2,000ft) long and approximately 90m (300ft) wide, with a bridge continuous 61 m (200 ft) deep and 12 m (40 ft) thick hull walls. The projected draft was 46 m (150 ft) and the tonnage was estimated to be more than 2 million tonnes (for comparison, an Essex-class aircraft carrier had a tonnage of around 30,000 tonnes); It was to have been made in Canada using, among other materials, 280,000 blocks of ice. In 1943 the Montreal Engineering Company Ltd. (now AMEC), at the request of Prime Minister Winston Churchill, accepted its first order from a foreign organization: the "Habbakuk project", a code name used to designate the unusual idea of the British admiralty. The initial project involved cutting huge sheets of ice from Arctic glaciers and transporting them to the mid-Atlantic for use as airstrips (a combination of an iceberg and an aircraft carrier). The project, however, soon proved impossible and the studies then shifted to the construction of a conventional boat, assembled with similar materials. The new project was perfected during the same year. The original material was replaced by a mixture of ice and cellulose, known as pykrete (named after the creator of the "Habbakuk project"). The ship's draft would have made docking in almost impossible