Prairie-Masker is a noise reduction system that was first used on United States Navy warships in the 1970's, as of the late 1990's the technology is used in several navies including the Australian, British and Canadian Royal Navies as well as the Hellenic Navy. In the US Navy it is used on Arleigh Burke class guided missile destroyers and Ticonderoga class guided missile cruisers.
The system is designed to prevent the identification or classification of a warship by masking its acoustic signature. Instead of hearing the sound of the engines running and the propeller spinning it creates a sound on sonar similar to rain hitting the surface of the water. There are two different components to this system, the Masker portion and the Prairie portion.
The Masker portion is designed to mask the ship's engine noise on enemy sonar and to also increase the ship's own sonar effectiveness by reducing self-noise. The Masker portion typically consists of two bands fitted to the outside of the hull adjacent the vessel's 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 within the hull where it is dissipated.
The Prairie portion is actually built into the ship's propellers, on older ships it was built into the hull above them. Small holes are built into the edges of the propellers through which compressed air is pumped thereby disguising the sound of the propeller as bubbles in the water.
The system is designed to prevent the identification or classification of a warship by masking its acoustic signature. Instead of hearing the sound of the engines running and the propeller spinning it creates a sound on sonar similar to rain hitting the surface of the water. There are two different components to this system, the Masker portion and the Prairie portion.
The Masker portion is designed to mask the ship's engine noise on enemy sonar and to also increase the ship's own sonar effectiveness by reducing self-noise. The Masker portion typically consists of two bands fitted to the outside of the hull adjacent the vessel's 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 within the hull where it is dissipated.
The Prairie portion is actually built into the ship's propellers, on older ships it was built into the hull above them. Small holes are built into the edges of the propellers through which compressed air is pumped thereby disguising the sound of the propeller as bubbles in the water.
Kathleen Nolan's call sign is eventually awarded to her as being "Cupid". This is also the real life first name of the helicopter co-pilot she flies with, Cupid Hayes
Huey pilot Rodney Poynter "Sunshine" is sometimes referred to as "Warrant" (usually by Kathleen), this is referring to his rank, which is Chief Warrant Officer Three (CWO3).
The first Greek frigate is called the Demeter, she is named after the Greek goddess of of the harvest and agriculture, Demeter presided over crops, grains, food and fertility of the Earth. The second Greek frigate is called the Nereus, she is named after the eldest son of Gia (the primordial goddess of the Earth) and Pontus (the primordial god of the Sea); Nereus was the main deity presiding over the Aegean Sea. The coat of arms on the third Greek frigate, the flagship Vellek and his lab is on, identifies it as the Proteus. Proteus was the son of the god of the sea Poseidon, Proteus was considered the god of rivers and lakes and was a shapeshifter who could change his form at will. Some also called Proteus "the god of elusive sea change" and he was attributed as being the one in control of the constant changing nature of the sea and the liquid qualities of the water. Thus if sailors sought good weather on the ocean they would pray to Poseidon and they would also pray to Proteus for the waters to remain calm, on both the sea and in rivers and lakes.