Greetings.

A local TV news show had a feature on a concrete canoe weighing only 16 pounds, which piqued my interest since I'm always looking for lightweight and durable boatbuilding materials. I'm assuming that you could make a boat like this simply by building an outer shell out of plywood plus an inner shell suspended at the proper height (perhaps by being attached to crossbeams resting on the outer shell?). Concrete would then be poured into the spaces between the two forms; if it's runny enough, I'm assuming that it should evenly fill the cavity. Something tells me that the process is a bit more complicated than this, though... do any of the boatbuilding gurus here have any experience with this sort of thing, or an educated guess as to how it's done?

Any help is appreciated.