PROBLEM TO BE SOLVED: To save power energy as much as possible by injecting air into water and then discharging from the bottom in small air bubbles, in contrast to the patent literature 1 premising consumption of great power energy at a compressor and the like, as well as to the patent literature 2 also requiring great power energy for feeding air through a water passage.SOLUTION: A hull frictional resistance reduction device is characterized by a cylinder provided inside a hull, having one end part of the cylinder connected to an air feeding opening of an air pipe, having the other end part connected to a discharge opening opened on a bottom outboard, and a water passage from a water intake opening opened outboard and the cylinder are joined in a tangential direction on the one end part side of the air feeding opening, the water intake opening and the discharge opening pass the cylinder, form one water passage, furthermore the water passage and the air passage are confluent in the cylinder, and water and air are discharged from the discharge opening.SELECTED DRAWING: Figure 1
展开▼
