Hello... Had this drawing for some years, always appealed to me, maybe it was the Vosper name. But at 43" it would be a lump for my transport.
Reduced the plan to approx 33" length, and decided to build it in balsa, Finance was the thing at the time. And Howes was selling DC Motors at £3 each, they were 385 i think, but just right for this model. They had a good voltage range, 3-18 Volts. Because it was decided to plank the model, finally settling on 1/8" square planks, because of the curves, Using 1/4" and 1/8"th Balsa. Also some tools were lying about from the Model Aircraft days, as in a balsa stripper, a great tool. 1/16" ply was used for the inner box longerons, No stringers were fitted, again because of the planking being used. The keel was a 1/4" balsa as was the formers/bulkheads. The 1/16"th ply used for the box assembly inner longerons, and 18" th square balsa used to plank the frame/hull. The whole assembly was tissue covered and doped accordingly, spray paint from local car accessory shop, twin screws and radio fitted , off to the pond for a first sail, she performed really well reacting to the twin screw independent motor control drive, she was also fitted with twin rudders,. Performance was not so good and a motor change followed. This turned out to be a very manoeuvrable boat, easy to transport and cheap to run. fair winds.. Regards Muddy

Forgot to mention this was about 2008 erra.. Things were a lot cheaper ...lol...
More pics. Regards Muddy...