Back of the serviette stuff but don't worry about that for now: we'll be building soon enough, but prior a discussion of some of the design elements to consider by way of a primer (as in our case aerodynamic considerations outweigh hydrodynamic).
Broadly speaking any rectangular surface extended into a plane is unstable and if it pitch up at all, will continue to do so. This applies to shallow hulls wholly unsuitable for managing swell ~ as hydroplanes demonstrate top left ~ beside deep multi-hulls that do manage rougher seas. The catamaran at bottom right is one such, but even these (like Campbell's 'Bluebird') are not immune at higher speeds.
A reliable aerodynamic solution to such departures is a tailplane or stabiliser pitched far behind centres of lift and gravity, which gives the leverage required to restrain pitch within limits. An alternative is triangular airfoils or delta-wings that stall during such departures and are therefore self-correcting: planing monohulls approximating such outlines are thus less prone to blow over than rectangular footprints ordinarily used in cats and hydroplanes.
Beyond 100 m.p.h. however powerboats do benefit from the air cushion that passes between the hulls of hydroplanes or catamarans, which is why the bulk of them are built that way. There are fast monohulls, but like the latter these also rely on their sheer extent and weight (besides their power) to sustain high speed upon swell.
What we want from the flat-cat in the sketch is ~ beside delivery and construction in flat-pack form ~ to try and retain the lightest possible weight within the outline of a vessel capable of such speeds, and with an efficiency and economy improved by an order of magnitude.
The world that ~ the way things look to be going ~ measures only speed regardless of the cost to the individual, society and the planet is hopefully in retreat. Speed alone, I told Shania Twain, don't impress me much and measures like kt/kW would be the better yardstick.
And indeed kg/m of length at point of manufacture: some among fast HDPE craft are pushing 300kg/m, which at the get-go I'd like to improve on by a factor of ten.
