For testing the boat as a straightforward 'flat-cat' without provision for lifting motors, we shall build a truncated version together that is curtailed at the end of the pontoon floats. Follow me through then as we work together to build the revised prototype.
You can build at metric scale or else imperial as used in the US and UK, converting the following feet-and-inches like so to metric measures: for 6', 3' and 10" sub 2.0, 1.0 and 0.25 metres (and use 2.40 or 2.50 metres to sub for 8' in extended versions).
All of this is dictated by suppliers in the US and around the world, supplying in either multiples of metres or else of feet. Crucial to the build of a shorter prototype is the fact that carbon fibre tubing often retails at 1.0 or 2.0 metres at a maximum and we can expect to migrate to exotic materials of this kind to reduce weight further.
Meanwhile extruded plastic tubing that is manufactured in the UK is retailed at either 1.0 metre or 3.0 metre lengths, with a considerable surcharge for the latter to account for the fact that parcel distributors here apply extra costs to carrying anything beyond a metre in length.
To begin, however, cut your longest spar to 6', another to 3' and two more to around the 10" mark depending on whether you've used rough-hewn timber (1" or 25mm) or PAR (3/4" or 21mm). I've gone with the latter here, and used 305mm minus 42mm as my guide.
We now use the four spars to build a 'picture frame' toward the rear of each pontoon, driving a screw in at each corner to secure.
