The surface piercing or ventilated propeller (image) is a propeller that is designed to intentionally cleave the water and entrain atmospheric air to fill the void, which means that the resulting gas layer surrounding the propeller blade consists of air instead of water vapour. Less energy is thus used, and the surface piercing propeller generally enjoys lower drag than the supercavitating propeller. The surface piercing propeller also has wedge shaped blades, and propellers may be designed that can operate in both supercavitating and surface piercing mode.
