Quite interesting...!

The lessons learned during the construction of the prototype revealed the full size Habakkuk (designed to be 2000-feet long, 190-feet high, and weighing 1.8 million tons) would need over 280,000 Pykrete blocks and take over 8000 men eight months to complete. Suddenly, "free" ice wasn't so free anymore...

http://www.de220.com/Strange%20Stuff/StrangeStuff.htm



The first layer of the ice blocks are in place. The corner pipes are being installed. Notice the insulation, which appears to be pine needles) up to 6-feet.
National Archives #80G702433



The second layer of Pykrete blocks are laid and the vertical coolant pipes are in place.
National Archives #80G702434

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