As a boat owner, how often have you thought about this idea, I can honestly say I've run this idea through my head for over 25 years , but always using the boat engine as the power source. Not sure how they power it, but it steers with the boats steering wheel.
Ugly, but it looks like it works.
Being a noticer, looks like this was filmed in Canada or Europe.
http://videos2view.net/fishing-boat.htm