RNLI-Severn
It's a ready built one marketed under the auspices of the RNLI itself. I bought it from a shop called Nauticalia. There are numerous stories about it on the www - overheting, sizing up motors etc. I was offered a refund by the shop but they had no replacements and the little man was/is really attached to it - even though now all he can do is float it in the bath. There are also stories of it being modified to full RC specs, but I don't want to go the pro route, just something he can use and have fun with as originally intended but with better motors (water-proof).
I was an engineer and I've modelled locomotives, mended clocks and built 1:1 racing motorcycles - not boats in any scale though. Trouble now is I can't hold anything steady, problems even to write. Despite being on the coast I know of only one model boat club - it's a good one but it's racing 'yachts' only and very pro too.