Ice Aircraft Carrier Project Habakkuk

Geoffrey Pyke proposed building an aircraft carrier from Pykrete - 86 percent sawdust and 14 percent water frozen together. Pykrete was as strong as concrete but floated and self-repaired. The ship would have been 2,000 feet long. A 60-foot prototype lasted an entire summer at Patricia Lake in Alberta. Cancelled when the refrigeration system alone would weigh as much as a conventional carrier.