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Britain's Plan To Build a 2,000 Foot Aircraft Carrier Almost Entirely From Ice (bbc.com)
dryriver writes from a report via the BBC: In World War 2, Britain was losing the Battle of the Atlantic, with German U-boats sinking ship after ship. Enter Project Habakkuk, the incredible plan to build an aircraft carrier from ice. The British government wanted a better way of battling German U-boats and needed an aircraft carrier invulnerable to torpedoes and bombs. Inventor Geoffrey Pyke came up with the idea of using solid blocks of ice, strengthened with sawdust, creating the material Pykrete, to build a ship big enough for bombers to land on. Winston Churchill became interested in the plan after Pyke pitched it to him. The proposed ship was to be 610 meters (2,013 feet) long and weigh 1.8 Million tons, considerably larger and heavier than today's biggest ships. It would have hull armor 12 meters (40 feet) thick. Work on building a proof-of-concept prototype started at Patricia Lake, Canada. But when it became clear that the finished aircraft carrier would take until 1945 to build, and cost 10 million pounds, the British government cancelled the project in 1943, and the prototype in Canada was scuppered.
http://www.discovery.com/tv-sh...
Basically, they tried to build a boat with 'pykrete' in the arctic and found that it fell apart PDQ.
They had a little more success building a boat with a mix of ice and sheets of newspaper, but it still didn't last an hour before coming apart.
NFW an aircraft carrier would ever manage to finish construction, let alone... y'know... launch aircraft.
Mayhaps not, but IIRC Mythbuster's constructions were not very big/thick. It's possible scaling up might provide better longevity as mass/volume goes up by the cube of the length. Icebergs tend to stick around for a while, and IIRC, tests showed Pykrete to melt slower than plain ice.
In the real world, Pykrete was never designed to be a miraculous substance that didn't melt. The aircraft carrier was designed - and its prototype built - to use electrically powered cooling systems to keep the ice solid. The thing that adding wood fibre brought to the table was that it turned ice from a brittle substance into a composite; for a modern composites analogy, the wood fibre acts equivalent to fibreglass or carbon fibre, and the ice acts equivalent to epoxy.
There've been a number of attempts to make structures "straight from the sea", and they've had success on the small scale but never been attempted on the large scale. One I kind of like is called "Biorock" or "Seacrete"; you build a steel skeleton in the shape of what you want, then run a small DC current through it; this causes minerals (mainly calcium carbonate, aka limestone) to precipitate out on it, forming a very hard steel-reinforced rock. Even better, it's self-healing, as anywhere that gets damaged becomes the easy path for current to conduct, and most growth switches to that area. Calcium and carbon dioxide, unlike some minerals (such as iron) are never in short supply in the ocean; carbon dioxide is quickly replaced by gas exchange with the air and sea life respiration, while calcium exchanges with the seafloor at a quick rate. If the electrical power source (which isn't huge) is carbon neutral, the construction acts as a carbon sink. And the electrical current oxygenates the water around the structure slightly, which leads to sea life flourishing. Indeed, the latter property is the only one that's successfully been exploited with biorock thusfar - growing artificial reefs (the growth rate has proven too slow for growing large structures like ships or artificial islands, mainly because the rock that gets laid down acts like an electrical insulator - the thicker it gets, the more the resistance).
Still, it'd be interesting to see some new approaches to get the growth rate up, such as meshes, "fuzzy" steel rods, maybe even conductive gels where wave action isn't of significance.
Is your job to sit under bridges and jump out at unsuspecting travellers?