went down to the marina again the other day (without the dogs) but with tape and chalk, and took some measurements. Was lucky enough to see a bloke I know who fetched a ladder for me so I could see on top and inside. She could be an interesting project, as the cockpit is quite deep and extends so far forward that the motor and batteries may be difficult to locate without getting her too bow heavy. Will get a roll of lining paper after Christmas and start drawing at 3/4" and 1" to the foot. There's not much to the inside - there's a towing post in the middle of the cockpit, and a door to the engine room which is stuffed full of a ginormous Gardner diesel engine - presumably a close relative of the old London bus engine used in the X craft! I think Jenkins stress the manoeuverability - interestingly the rudder is not only balanced but also has a length of round bar welded down the after edge, to give the "extension by turbulence" we have seen debated on this forum before. But interesting to see it as a bar, rather than a piece of angle. Also see extremely simple but presumably effective rudder stop welded to botom of skeg. The 38" propellor may be a bit of a challenge - methinks a bit of gearing down from the motor may be needed but I will ask later if I get that far. However I must not get too enthusiastic yet - MUST finish the current project first!
Thank you all for your comments - I'll be visiting the sites referred to.