The individual systems and equipment vary slightly in numbers, locations and capacities between the three classes of ships. You should concentrate on the information concerning the class of ship you expect to report to. To support this mission, various ship s silencing features are available. DD-963 Engineering Spaces Masker air absorbs the noise generated by equipment in the main engineering spaces. The air needed for the masker air system is supplied from the bleed air header to the emitter rings on the hull surrounding the main spaces.
Prairie air is used to reduce the noise created by the ship s propellers as they turn in the water.
The air is released from the edges of the propeller blades. This air is also supplied from the bleed air system. Along with the use of masker and prairie air, other types of sound deadening devices are used in the engineering plant. Flex hoses are used to connect pumps to piping systems. These hoses will absorb the surging of equipment during initial start-up.