rhodyne

Ah...finally found a good pic set and description and it turns out to be at Stevensons site in one of their 'Captain Ply' pages. I have not linked any pictures because I don't want to irritate anyone but this last page link is directly to the motor stuff you were asking about.

Their site doesn't have a whole lot of data about that drive setup (it is in the plans) but basically it is a trolling motor that has been hacked and sealed into a ply/foam/fiberglass chunk that looks like an outboards lower unit. Has a bolt hole in the top of it and a bracket on the transom so it hinges and can be quickly dropped or pulled. The plans don't call for a way to hold it down so it won't reverse too well. You can find another motor option - and a pretty good build log - at the Weekender: Spirit site.

That is a Stevensons Weekender and that video is used in their 'video build' demos.