In 1942, the allies were suffering heavy losses of merchant ships to German U-boats as a result of the limited range of patrolling aircraft. Lord Louis Mountbatten suggested building large ships made of ice to protect allied merchant ships and possibly as a platform to launch an offensive from. Mountbatten, the Chief of Combined Operations, an organization responsible to the Chiefs of Staff for the development of equipment and special craft for offensive operations, had been advised by one of his scientists, Geoffrey Pyke, that huge ships of up to 4,000 feet long and 600 feet wide could be made cheaply and in large numbers.
Winston Churchill, Britain’s PM was enthusiastic of the project and saw to it that it got underway. In 1943, it was discovered that by adding wood pulp to the water before freezing, a very tough material was made which was called ‘pykrete’, in honor of Geoffrey Pyke. It was reported that when demonstrating the idea to a group of high brass military leaders, Mountbatten fired a shot at an ordinary block of ice, which shattered into little pieces. However when he fired at the Pykrete, the bullet bounced right off and almost hit the Chief of Air Staff Sir Charles Portal.
Construction on a prototype began at Patricia Lake in the Canadian Rocky Mountains, and it was determined that the hull needed to be at least 35 feet thick in order to contain damage from bombs and torpedoes. However before tests were complete, the Battle of the Atlantic had been virtually won and with the construction underway of the new aircraft carriers, the project was reluctantly abandoned in August 1943.