Reduction of ship's hull friction by compressed gas - involves ejecting gas through apertures in hull wall to separate boundary layer

摘要

The system involves the use of gas or a fluid medium to reduce the surface friction between a submerged body and water, where there is relative movement between the body and the surrounding water. The technique is particularly applicable to a ship's hull. Gas is pumped into a cavity (2) in the hull wall from which it emerges through holes (5), slots or pores in the material of the hull to separate the boundary layer from the hull surface. Frictional resistance is thus reduced. Exhaust gas or steam from the engines of the ship may be used.