The Knuckleduster's straight-sided hull was of all-metal (Alclad) box-section construction, from the bow as far as the pointed main step at the rear of the planing bottom; aft of the main step the fuselage was of monocoque construction.
In terms of its hull design, the Knuckleduster featured an all-metal, box-shaped structure that spanned from the bow to the pointed stern section on the planing surface; beyond this point, the fuselage became a single, integrated unit.