The U.S. Navy employs the Prairie Masker system to disguise the sound of its warships from enemy submarines.

Sound of Rainfall

Variations of the Prairie Masker system have been used by the U.S. Navy since World War Two. The system effectively masks the engine noise of warships traveling on the ocean’s surface from enemy submarines that are listening below. Instead of hearing engines and machinery, submarine technicians conducting acoustic analysis with sonar hear a sound similar to rain falling on the ocean.


This allows U.S. Naval warships to avoid detection and evade hostile submarines. For this reason, the Prairie Masker has been a key part of U.S. anti-submarine warfare for more than 50 years. 

The Prairie Masker system works using two bands that are fitted on the bottom of a warship near the engine rooms. Compressed air is pumped into the bands below the ship, creating a barrier of air bubbles that dulls or blunts the sound of the engines. A third band is sometimes placed near a ship’s propellers to further reduce noise levels. This system can make it difficult for submarines to hear a warship passing above on the ocean’s surface. Many other Navies around the world have adopted similar noise reduction systems for their warships as part of an anti-submarine warfare solution.