The Story of Pykrete: That Time the Navy Built a Ship Out of Ice and Sawdust

The Story of Pykrete: That Time the Navy Built a Ship Out of Ice and Sawdust

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World War 2 was a period of rapid innovation, one of the scant few upsides of war. Crazy ideas were being floated left and right. An aircraft carrier built onto an iceberg was one of them. Though that never saw the light of day, a test ship made from ice was built that was 18 meters long and 1,000 tons on Patricia Lake in the Canadian Rockies.

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It was all the brainchild of Geoffrey Pyke (hence ?Pykrete?) and it nearly came to a premature end when it was discovered that ships built from ice melt too quickly and don?t withstand shells and bullets as well as predicted. Within the Summer, the ship melted to nothing. But then Geoffrey Pyke had an epiphany.

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He recalled reading a report by Herman Mark about how adding sawdust, paper or other fibers to ice in a precise ratio resulted in a material which melted much more slowly, and was about as resilient to impact as concrete. Max Perutz remembers the outcome of this project: ?When we fired a rifle bullet into an upright block of pure ice two feet square and one foot thick, the block shattered; in pykrete the bullet made a little crater and was embedded without doing any damage.?

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Geoffrey Pyke reported the breakthrough to Winston Churchill in a manner that would be unthinkable today, and which makes an amusing mental picture: ??I was sent to Chequers to see the Prime Minister and was told he was in his bath. I said, ?Good, that?s exactly where I want him to be.? I nipped up the stairs and called out to him, ?I have a block of a new material which I would like to put in your bath.? After that he suggested that I should take it to the Quebec Conference.?

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It was far from the only such colorful demonstration. According to Lord Mountbatten, at the Quebec Conference of 1943 he brought a block of pykrete along to demonstrate its potential to the entourage of admirals and generals who had come along with Winston Churchill and Franklin D. Roosevelt.

He entered the project meeting with two blocks and placed them on the ground. One was a normal ice block and the other was pykrete. He then drew his service pistol and shot at the first block. It shattered and splintered. Next, he fired at the pykrete to give an idea of the resistance of that kind of ice to projectiles. The bullet ricocheted off the block, grazing the trouser leg of Admiral Ernest King and ending up in the wall.

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Sadly, though the test ship made from ice did get built, the Pykrete prototype did not. The Allies were looking as though they would achieve decisive victory soon, and funds were scarce anyway. Pykrete was never used to build any military vessels, but not for lack of merit.

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Pykrete is one good idea that was not lost to time, but picked up, dusted off, and occasionally put to good use. The Pykrete Dome Project in 2014 achieved successful construction of the world?s largest ice dome, most of which consisted of pykrete. The upper section, being under much less stress, could be made from regular ice without danger of collapse.

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A small boat made from Pykrete was also built and tested on Mythbusters, as well as the British equivalent, ?Bang Goes the Theory?. Results were?what you might generously call ?varied?. Probable errors in their Pykrete formula sent Bang Goes the Theory?s vessel straight to the bottom before long:

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Perhaps not a hobby for amateurs. At any rate, Pykrete?s story is not over. It still has many promising peacetime applications, like the basis for floating air bases in the polar regions, which are sure to become more and more politically important as the ice continues to melt and the currently accessible oil deposits dwindle.

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What would you use Pykrete for? Nordic seastead? Hardening an Antarctic base against attack? Sound off in the comments.

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