Hydrofoils

The Water Bird

I wanted to post not only this video (h/t Anchoress) but some more detailed information about how the thing works, but I'm striking out. All I can find out is that it's a hydrofoil. It seems to be manufactured in China. Here's one for sale on eBay for about $300-- from Australia.

An Anchoress commenter supplied this:

I saw a show on the TV just the other day that featured this twin wing design. US Special Forces (Seals) are testing a small underwater version that seems to require something like one third the energy of swim fins. It straps on below the knees and the swimmer uses (what looked like) a dolphin kick to move the apparatus. A three-way race against submerged swimmers with this design vs flippers vs barefoot had this design far far ahead and arriving much less tired.

And that sounded interesting, too, but I couldn't find anything with a net search.