Project Habakkuk

Project Habakkuk or Habbakuk (spelling varies; see below) was a plan by the British in World War II to construct an aircraft carrier out of Pykrete (a mixture of wood pulp and ice), for use against German U-boats in the mid-Atlantic, which was out of range of land-based planes.


The Habakkuk, as proposed to Winston Churchill by Lord Mountbatten and Geoffrey Pyke in December 1942, was to be approximately 2000 ft long and 300 ft wide, with a deck-to-keel depth of 200 ft, and walls 40 ft thick.1 It was to have a draft of 150 feet, and a displacement of 2,000,000 tons or more, to be constructed in Canada from 280,000 blocks of ice.3 (For comparison, an Essex-class carrier displaced 35,000 tons.) In 1943 Montreal Engineering Company Ltd.—now AMEC—at the request of British Prime Minister Winston Churchill, undertook its first-ever commission from an outside organization: Project Habbakuk, the code name for an unusual idea originating with a scientist in the British Admiralty. The plan called for breaking off huge sheets of ice from the Arctic icecap, towing them to the war zone in the mid-Atlantic, and using them as landing fields for aircraft—a sort of combination iceberg-aircraft carrier. When that idea proved not feasible, research shifts to investigating the possibility of building a huge ship of more conventional design—entirely out of ice. The idea was scrapped the same year. The building material was later changed to a mixture of ice and wood pulp known as Pykrete after Pyke, who proposed the Habakkuk project — the material was invented by others. The ship's deep draft would have kept it out of most harbours. Inside the vessel a refrigeration plant would maintain the structure against melting. The ship would have extremely limited manoeuvrability, but was expected to be capable of up to 10 knots (18 km/h) using 26 electric drive motors mounted in separate external nacelles (normal, internal ship engines would have generated too much heat for an ice craft). Its armaments would have included 40 dual-barrelled 4.5" DP (dual-purpose) turrets and numerous light anti-aircraft guns, and it would have housed an airstrip and up to 150 twin-engined bombers or fighters.

The Habakkuk was imagined to be virtually unsinkable as it would have effectively been a streamlined iceberg or floating island kept afloat by the buoyancy of its construction materials, and to be highly resilient to damage by virtue of its sheer bulk.

It was projected to take £70 million and 8,000 people working for eight months to construct it, an expenditure which the British were unwilling to make at the time on such an experimental craft. Experiments on ice and pykrete as construction materials were carried out at Lake Louise, Alberta, and a small prototype was constructed at Patricia Lake, Alberta, measuring only 60 feet by 30 feet (18 by 9 m), weighing in at 1,000 tons and kept frozen by a one-horsepower motor.3 Work on the project continued through 1943, but major doubts as to feasibility had surfaced by October, and abandonment was recommended in January 1944, by when the Atlantic Gap had already been closed by long-ranged land-based aircraft. It took three hot summers to completely melt the prototype constructed in Canada. The use of ice had actually been falling out of favour before that, with other ideas for "floating islands" being considered, such as welding Liberty Ships or landing craft together (Project TENTACLE).2 The ice Habakkuk itself was never begun.

Shooting incident

At the Quebec Conference of 1943 Lord Mountbatten brought a block of Pykrete along to demonstrate its potential to the bevy of admirals and generals who had come along with Winston Churchill and Franklin D. Roosevelt. Mountbatten entered the project meeting with two blocks and placed them on the ground. One was a normal ice block and the other was Pykrete. He then drew his service pistol and shot at the first block. It shattered and splintered. Next, he fired at the Pykrete to give an idea of the resistance of that kind of ice to projectiles. The bullet ricocheted off the block, grazing the trouser leg of Admiral Ernest King and ended up in the wall. The Admiral was impressed by Mountbatten's unorthodox demonstration.

Cultural references

The ship appears in alternate history fiction; for instance, it appears as a boss unit in Warship Gunner,5 Commander and Warship Gunner 2.6

A similar project is undertaken in Harry Turtledove's Darkness Series as a floating base for dragons, the fantasy world's analogy for aircraft.

The ship is also seen in Zack Parson's novel "My Tank is Fight!"


The project's code name seems to have been consistently (mis-)spelled Habbakuk in the Admiralty and Government documents at the time. This may in fact have been Pyke's own error, as at least one early document apparently written by him (though unsigned) spells it that way. (However, post-war publications by people concerned with the project, e.g. Perutz and Goodeve, all restore the proper (one 'B' and three 'K's) spelling.) The name is a biblical reference to the project's ambitious goal: "…be utterly amazed, for I am going to do something in your days that you would not believe, even if you were told." (Habakkuk 1:5, NIV)
David Lampe in his book, Pyke, the Unknown Genius, states that the name was derived from Voltaire's Candide and was mispelt by his Canadian secretary. The name stuck and was never corrected. The reference to Bible appears to have come after the war when journalists were told about part of the project and they connected the Biblical text with the name.


The Habakkuk design received criticism, notably from Sir Charles Goodeve, Assistant Controller of Research and Development for the Admiralty during World War II.4 In an article published after the war Goodeve pointed out the large amount of wood pulp that would be required, enough to affect paper production significantly. He also claimed that each ship would require 40,000 tons of cork insulation, thousands of miles of steel tubing for brine circulation, and four power stations, but that for all those resources (some of which could be used to manufacture conventional ships of more effective fighting power) Habakkuk would only be capable of six knots of speed. Much of his article also contained extensive derisive comments about the properties of ice as used for ship construction.


Further reading

  • Perutz, M. F. (1948). "A Description of the Iceberg Aircraft Carrier and the Bearing of the Mechanical Properties of Frozen Wood Pulp upon Some Problems of Glacier Flow". The Journal of Glaciology 1 (3): 95–104.

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