Force = thrust − aerodynamic drag − grade force. Traction is capped by μmg cos(θ). Stopping distance = v²/(2μg). Static roll threshold = atan(track/(2 × COM height)). Suspension period T = 2π√(m/k).

Fixed 120 Hz semi-implicit Euler integration. Simplifications: planar rigid-body dynamics; roll and pitch are first-order approximations; water is visual only; no full fluid pressure or collision response. Energy is approximate positive mechanical work.