On reading over the description of the Cornwallis,i noted this
"The model is not intended to be kept afloat for long periods of time but to be recovered after each operating period on to its own purpose designed road trailer and returned home to be washed down. For this reason, the materials used are not necessarily of a marine specification."
For £7,500 ono,i would expect more than this,..who in their right mind would build a boat and "Not use"materials that were not up to the purpose they were intended for ,as for,not long periods,...its a lot of dosh to fork out, just to have it in the water for an hour or so,
Wullie