I saw this on a History Channel special called Weird Weapons of the Allies. It was a British aircraft carrier made of ice, wood, and sawdust.
The mixture of ice and sawdust is called pykrete, named after its inventor,
Jeffrey Pyke, who'd created it. The aircraft carrier, whose dimensions I forget,
was called HMS Habbakuk. It had been built, it would have had MILES of piping
for cooling the ship. What do you think would have happened if she'd been built?