Prairie-Masker

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A noise reduction system fitted to some warships of western origin. The Masker portion consists of two bands fitted to the outside of the hull adjacent the vessels engine rooms, compressed air is then forced into the bands and escapes through machined perforations to create a barrier of air bubbles in the sea about the hull, thus trapping machinery noise. Prairie works via the same principles but is fitted either near to or on the ships propellors. The systems are designed to prevent classification/identification by radiated noise of the warship in question by acoustical analysis ie by a hostile submarine.