Abstract: An integrally moulded plastic outboard motor boat hull structure is provide with reinforcement at its transom region. The reinforcement is in the form of gusset members which integrally connect the transom region to stiffening members that longitudinally extend between the bow and stern ends of the boat hull. An intermediate saddle member connects the outboard motor to the transom region, with the saddle member being preferably connected to at least one of the gusset reinforced longitudinal stiffening members. The overall structure serves to both reinforce the transom region, and transfer the dynamic motor forces away from the transom region, thereby significantly reducing the possibility of flex cracking within the transom region.