A boat drive system is provided for a power boat which includes an engine having a drive shaft, connected to a pair of propeller shafts. The drive system includes a primary gearbox and opposed outboard gearboxes. The primary gearbox includes a housing and a gear arrangement connected to the engine shaft and the outboard gearboxes, which are connected to the primary gearbox by a transverse shaft, include a housing and a gear arrangement connected to associated propeller shafts. A cooling system is provided including a cooling pad for each gearbox. A support system is provided for each outboard gearbox including a cradle connected to the bearing points on the hull. The engine includes an adapter plate attached to the primary gearbox for movement of the primary gearbox with the engine. In a modified drive system only one outboard gearbox is used in conjunction with a single engine. In another modified drive system a single engine and propeller are used in conjunction with a gearbox having a take-off shaft.