My understanding is a wire frame is coated with stiffer concrete. For example a chicken wire canoe is plastered with stucco. Concrete is not that strong by itself, it usually needs some sort of reinforcement. A male mold could be covered with a loosely woven fabric and coated with a runnier mix. This would not be much different from a way you can make fiberglass style boats.

> 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.