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Pykrete carrier


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Here is a short article about the proposed aircraft carrier made out of ice. While the project was impractical for many reasons, it should be noted that the test article took 3 summers to melt, and a modern replica (built by the Mythbusters for their TV show) did work. Some large illustrations at link


Churchill Pykrete carrier would have been three and half times longer than the US Gerald Ford Carrier

Winston Churchill had a project to produce a 2.2 million ton pykrete (ice and wood pulp) aircraft carrier that would have been 1200 meters long and 180 meters wide. This would have made it 3.5 times longer than the US Gerald Ford or Nimitz class carriers which are each about 330 meters long.

The final design of Habbakuk II (bergship) a displacement of 2.2 million tons. Steam turbogenerators were to supply 33,000 hp (25,000 kW) for 26 electric motors mounted in separate external nacelles (normal, internal ship engines would have generated too much heat for an ice craft). Its armament would have included 40 dual-barrelled 4.5" DP (dual-purpose) turrets and numerous light anti-aircraft guns, and it would have housed an airstrip and up to 150 twin-engined bombers or fighters.

In the 15 April 2009 episode of the U.S. TV show Mythbusters Jamie Hyneman and Adam Savage built a small boat out of a modified version of pykrete, using newspaper instead of wood pulp. They successfully piloted the boat in Alaskan waters at a speed of 25 miles per hour (40 km/h) and inferred that it is possible to build a boat out of pykrete. They also concluded that pykrete lived up to its purported properties of being bullet-proof, stronger than ice and taking longer to melt than ice. However, they expressed doubt that an aircraft carrier made of pykrete could have survived for long. The conclusion was "Plausible, but ludicrous.

They determined via experiments that the optimum structural properties were given by a mixture of 14 per cent wood pulp and 86 per cent water. The problem of plastic flow had become serious and it was obvious that more steel reinforcement would be needed, as well as a more effective insulating skin around the vessel's hull. This caused the cost estimate to increase to £2.5 million.

The final meeting of the Habbakuk board took place in December 1943. It was officially concluded that "The large Habbakuk II made of pykrete has been found to be impractical because of the enormous production resources required and technical difficulties involved."

It was planned to
* have a range of 7,000 miles (11,000 km)
* be able to withstand the largest waves recorded
* it was to be torpedo-proof, which meant that the hull had to be at least 40 ft (12 m) thick
* heavy bombers were to take off from it, which meant that the deck had to be at least 2,000 ft (610 m) long

Steering also raised problems; it was initially projected that the ship would be steered by varying the speed of the motors on either side, but the Royal Navy decided that a rudder was essential. However, the problem of mounting and controlling a rudder over 100 ft (30 m) high was never solved.

The use of ice had actually been falling out of favour before that, and other ideas for "floating islands" had been considered, such as welding Liberty Ships or landing craft together. It took three hot summers to completely melt the prototype constructed in Canada.
Here's a picture of Pyramid Lake where Project Habakkuk was conducted. In 2012, 1 CMBG HQ & Sig Sqn SHQ Tp did a three day PD session in Jasper, and Project Habakkuk was one of the topics we covered.  As you can see, the view there is spectacular!
Thucydides said:
.... a modern replica (built by the Mythbusters for their TV show) did work ....
Somewhat, anyway ....
.... In 2009, the Discovery Channel program MythBusters episode 115 tested the properties of pykrete and the myths behind it. First, the program's hosts, Adam Savage and Jamie Hyneman compared the mechanical properties of common ice, pykrete and a new material specially created for the show, dubbed "super pykrete", using newspapers instead of woodpulp. Both versions of pykrete indeed proved to be much stronger than the chunk of ice, withstanding hundreds of pounds of weight. The super pykrete was much stronger than the original version.

The MythBusters then built a full-size boat out of the super pykrete, naming it Yesterday's News, and subjected it to real-world conditions. Though the boat managed to float and stay intact at speeds of up to 23 miles per hour (37 km/h), it quickly began to spring leaks as the boat slowly melted. After twenty minutes the boat was deteriorating, and the experiment was ended. The boat lasted another ten minutes while being piloted back to shore. Though the boat worked, it was noted that it would be highly impractical for the original myth, which claimed that an entire aircraft carrier could be built out of pykrete.  Their conclusion was "Plausible, but ludicrous", since it would involve building vessels out of tens of thousands of tons of the material that would sink without being kept cool.

The MythBusters test was done at or slightly above freezing temperatures and generally proved that pykrete as a material was not better than other alternatives. Their vessel did not contain refrigeration units keeping the pykrete cold as the original plans called for and the boat had a much thinner construction than the ships proposed in World War II ....
Now, for structures in cold weather, as attached?  Maaaaaaaaaaaybe ....
Hmmmmm....a Navy that just seems to melt away...

Oh, wait, sorry. We've got one.