METHOD OF SILENCING UNDERWATER SOUND AND SHIP EQUIPPED WITH SILENCER Russian patent published in 1999 - IPC

FIELD: silencers. SUBSTANCE: method of silencing underwater sound produced by ship driven by one or several screws consists in blowing air and/or another gas into backwash; turbulence of backwash causes mixing of air and/or another gas and water and crushing of gas bubbles. Great number of bubbles have diameter of from 1 to 20 mm and diameter of large bubbles reaches 100 mm. Resonance size of largest bubbles silencing the sound corresponds approximately to lower limit of required silencing frequency. Ratio of volume of gas delivered to water and volume of water jet created by backwash ranges from 0.05 to 1.5%. Gas is blown into water in such way that zone of gas bubbles embraces underwater portion of ship's hull almost fully. Power required for forming gas bubbling ranges from 1 to 7% of ship's propulsive power. Considerable number of bubbles remain at distance of 80 m from ship behind her. Ship used for realization of this method is provided with equipment for blowing bubbles of air and/or another gas into backwash; as a result, bubble zone of required form may be obtained without complex devices. EFFECT: enhanced efficiency. 9 cl, 4 dwg