"Pykrete" was first developed in 1943 at Brooklyn Polytechnic's Cold Research Laboratories by scientists working under Geoffrey Pyke. These researchers created a mixture of between four and fourteen percent wood pulp in water. The slushy mixture was frozen into a material first named piccolite. Later it became known as pykrete.

Testing of this material showed astonishing strength. The crush resistance of clear ice is between 250 and 1,300 PSI, but pykrete's crush resistance proved to be more than 3,000 PSI. The wood pulp appeared to insulate the pykrete, making it considerably more stable at high temperatures than ordinary ice. A small expenditure of energy would keep it frozen.

Pyke's "Habbakuk memorandum" came up with several cockeyed ideas. The most famous one involved a giant aircraft carrier made completely from pykrete. This theoretical ship would have been two thousand feet long and would have had a thirty-foot-thick hull. Pykrete's specific gravity was found to be lower than that of ice, and this meant that an ocean-going vessel made of the substance would be almost unsinkable. The maximum speed of such an ungainly vessel would be severely limited, but because of pykrete's invulnerability this would not matter in a combat environment. Calculations suggested that if a vessel of this type were hit dead on by a torpedo, the blast would produce a crater only three feet deep and about twenty feet in diameter. This damage would be almost unnoticeable on the vessel's thirty foot thick sides. Pyke and his team suggested that this iceberg aircraft carrier could survive waves one hundred feet high, and that incendiary attack would hardly damage them.

This vessel's innards were to contain freezing plants, workshops, hangars and living areas. Their runways would launch any military aircraft then in use. Each iceberg aircraft carrier would contain sufficient fuel for a seven-thousand-mile non-stop cruise. Pyke suggested that freezing units could circulate cold air throughout cardboard tubes, frozen into the pykrete. This would, he theorized, keep the ship from melting. Cork sheathing was suggested to protect the exterior of the ships against possible evaporation.

Despite sounding like complete lunacy to modern ears, the idea was actually very positively received by both Lord Mountbatten (Chief of Combined Operations) and British Prime Minister Winston Churchill. They envisaged it as a way to close the "air gap" over the Atlantic Ocean by providing a near-indestructable mobile launch platform for air operations. A 1000-ton test ship made of pykrete was actually built in a lake in Alberta, Canada. It withstood impressive amounts of strafing and bombing, but the project was ultimately cancelled and the prototype destroyed. For more information see:

http://www.combinedops.com/Pykrete.htm

http://ourworld.compuserve.com/homepages/pete_hall_uk/pyke.htm

http://home.att.net/~Storytellers/sewrtech.html