I have merged the topics and will try to consolidate them a bit as I have been getting queries etc about the definitive rules.
Hopefully we will end up with a plan in Imperial and Metric but both, but having a standard motor, power etc.So the British Mayhem rules (if you all agree) are:Construction
Size 18" (460mm) long, 8" (200mm) wide hull profile as per plans. Construction material, anything, any weight. No sharp corners on hull edge to stop damage to other boats in combat Superstructure
There must be a superstructure above the decks Min size 4"x4"x4" (100mm x 100mm x 100mm) whole or in parts, other than that whatever you like, tugs, warships, tanks, house, duck, sailing, no puffers!Drive
Motor will be 540 (Speed 600) or less, any gears reductions clutches etc allowable but must not be used to steer the boat in any way. Any propshaft type Single propeller 11\2 inch (38mm) Dia.Power
Max battery voltage 7.2v any battery typeSteerage
Any rudder arrangement including nozzles allowed, any shape or quantity however, max surface area (fixed or moving) not to exceed 4 Sq inches 2500 Sq mm.