In 1942, the British attempted to construct an aircraft carrier using pykrete, a mixture of ice and wood pulp.
During World War II, Britain sought ways to protect naval landings and Atlantic convoys in waters beyond the reach of aircraft. The challenge was compounded by shortages of steel and aluminum, which were needed for other purposes. Engineer Geoffrey Pyke proposed building an aircraft carrier from ice. His concept involved leveling an iceberg, natural or artificial, to create a runway, hollowing it out to shelter planes, and embedding frozen motorboats along its sides. To enhance the ice's properties, it was reinforced with wood pulp.
Geoffrey Pyke was not the first scientist to suggest such an application for ice. German scientists in the 1930s also proposed a concept for a floating ice island. However, the project was soon abandoned.
Scientists strengthened ice by incorporating wood pulp. The optimal pykrete ratio is 14% pulp and 86% water. This material proved more robust than natural ice, melting more slowly and exhibiting less buoyancy in water. A fortuity occurred during a strength test, when an incident involving a gunshot showcased pykrete's resilience. At the Quebec Conference of 1943, Lord Mountbatten demonstrated pykrete's capabilities to admirals. Mountbatten presented two identical blocks—one of regular ice and the other of pykrete. Firing his service pistol at them, the ice block shattered, while the pykrete block deflected the bullet, tearing Admiral Ernest King's trouser leg before lodging in the wall.
Habakkuk Project (Aircraft Carrier)
A decision was made to construct a large-scale model in Canada's Jasper National Park. Necessary materials included 300,000 tons of wood mass, 25,000 tons of wood fiber insulation, 35,000 tons of timber, and 10,000 tons of steel. The cost was estimated at £700,000. However, technical difficulties with cooling and maneuvering the carrier arose during construction. Adverse weather conditions impeded progress, project costs escalated, and technological requirements evolved. For instance, the Royal Air Force determined that heavy bombers should be able to take off from the carrier, necessitating a 610-meter flight deck.
The Impracticality of the Project
The final board meeting for Project "Habakkuk" took place in December 1943. The project was officially deemed impractical due to its immense production demands and technical challenges. The pykrete prototype of the carrier built in Canada continued to melt for three more years.
Pykrete 2.0: Reinforced Ice
The project's legacy endures. In modern times, attempts have been made to apply pykrete's principles. In 2019, a group of scientists from Tomsk, Krasnoyarsk, and Moscow developed a composite material based on ice. Instead of wood pulp, threads (ranging from linen to polymers) soaked in epoxy resin are frozen into the ice, rendering it as strong as metal, as light as plastic, and resilient to temperature changes. The material was envisaged for constructing bridges and platforms for drilling rigs in the Arctic. However, information about the application of reinforced ice in public sources is scarce.