A conventional screw propeller works within the body of water below a boat hull, effectively "screwing" through the water to drive a vessel forward by generating a difference in pressure between the forward and rear surfaces of the propeller blades and by accelerating a mass of water rearward.
Unlike hydrofoils, which use underwater wings or struts to lift the vessel clear of the water, standard jetboats use a conventional planing hull to ride across the water surface, with only the rear portion of the hull displacing any water.