Here is how it looks from its best side. A block at the stern is reserved for the rudder, which if retained inboard allows for the boat to be stood upright for storage.
Aside from this displacement has been adjusted by use of a diagonal sheet of foam, which should pitch the motor clear of the waterline at rest.
The keel could in theory be sandwiched by rectangular sheaths of plastic sheet; whilst this would look rather better it would complicate the aerodynamics.
The reason a cat is a simpler build is the total absence of asymmetric effects deriving from a single propeller. This produces a swirl in the direction of turn that impinges on the tailplane (or hear the keel), rotating the craft around its axis unless compensated.
Conventionally this compensation has taken the form on single-engine aircraft thus:
(a) offsetting the engine mount
(b) offsetting the tailplane
(c) rigging the wings at different angles of incidence
Tricky eh? The only means of compensation available to this bad boy will be input via the rudder.
Whether this will require the speed of a flight-control computer remains to be seen.
