The Electric Boat Association is a U.K. based, non-profit organization that any of us interested in electric power/electric boats should check out. They have a nice web site with vendor information (mostly geared around European suppliers, but in this internet age that’s easy to deal with), technical hints, member pages, information on solar installations, picture galleries, etc.
The technical section includes a couple of spreadsheets that you can download and use to help estimate electric power requirements for your boats.
The member’s section is definitely worth a look… some beautiful, classic craft shown here. Many turn of the century (we’re talking 1900’s not 2000’s :-)) boats. We often don’t remember the history of electric boating on the Thames.