build a little bicycle like propeller system to strap on the main beam, and a little recliner/recumbant seat to push against, and viola' you've got propulsion. Maybe even lighter than a set of oars....
I was toying with idea of sidewinder
http://www.recumbents.com/wisil/hpb/boat98.htmjust place cranks into center and pedal from sides, with normal sailing position. On one tack pedal forward, on another pedal in reverse
From power's output point of view there is no difference.
However I decided that oars are simpler
and therefore, more reliable.
