I'm not so sure about the outboard engine suggestion.....were looking at two engines, each slightly more powerful than those used on the old Sinclair C5, with an output of around 300W. The propellers are a problem, according the drawings, once scaled down the diameter is 60mm (4 Bladed), I'm reliably informed that this is way to small and we need 90 - 95mm, however, 60mm is all we have room for between the centreline of the shaft and the hull, we can angle the engines a bit more but it's not going to make a great deal of difference.
The modelling clubs suggestion is a super idea and I'll get on to that this week. As far as the photos are concerned I'm having trouble reducing the size, as soon as I can get them reduced I'll upload them, hopefully this week.