Electric trolling motor for a canoe....made from a cordless electric drill and other bits and pieces.
He's thinking, but that is a short term solution. Those right angle gearboxes, waste energy in transfer, and don't hold up very long under load. (I've destroyed several of them. Both the cheap stuff and the professional level) He would do better with a single pivoting yoke on the transom, and a straight shaft with no energy lose. (Like they do with gas mud motors).
I have no doubt that you are right. I'm not suggesting that it is the best solution or the only solution....just offering it as a novel solution, arrived at by thinking a little outside of the square, and using repurposed bits and pieces that may be salvaged from other things with unrelated uses. The video clip highlights that in a TEOTWAWKI environment there are creative ways of adapting and repurposing material to meet an emerging need that has no convenient store bought, off-the-shelf availability.