Things have m,oved on a little [well, quite a lot now] since I started this thread, but will continue it to show the completed boat.

I fitted 3 graupner speed 400’s to the hull, as I wanted it to both look the part, having 3 props underneath as well as giving it enough thrust through the water to get it to plane correctly. I feel simply putting a single propeller under such a boat is defeating the object and once on a static display stand, looks like a cheapened conversion, rather than a full build.

I used SHG universal “dog bone” couplings and attached them to 2mm stainless steel propshafts,  the brass robesch propellers are 20mm diameter.

When driving all 3 props at speed i appreciated there could be some “turning difficulty”, so wanted to be able to cut out the inner motor on tigth turns. Ok, so plenty of electronic devices about to do this for you, but  they cost money, so how to do this cheaply? Easiest solution was from the magazine again. Simply fit 2 micro switches on a plate that surrounds the rudder servo, so as the rudder servo turns, it hits against one of the switches, and it cuts power to the inner engine. Fit a second servo on the opposite side of the rudder post arm and that cuts the other inner engine on the opposite turn. Word of warning, take some time to get f these micro switches right, otherwise even on a slight turn, it will cut a motor out, and you really only need this on faster tighter turns to keep the boat planing on turns.  Afterall, 2 micro switches and a few bits of plastic for the base is what? less than £3.50 all in, whats the cost of an electronic item– yeah in excess of £50, thats a lot of money if you aint got it to spare.