: I saw one last year at Lake Wintergreen. A club for UNH had built
: one and were practicing paddling it in preparation for a contest
: with other schools. They looked quite wobbly. I shared some
: sculpture tips on how to make the concrete lighter so I hope
: they won.

Concrete canoes have been around awhile. When I attended UNH in the seventies one of the engineering clubs had built one.