Sonar decoy
A sonar decoy is a device for decoying sonar. Most are released from submarines to act as a false target.
Submarine decoys[edit]
The first submarine decoys were the German Bold fitted to U-boats of World War II. These were a pellet of calcium hydride in a simple metal container. On contact with sea water, the calcium hydride decomposed to produce a trail of hydrogen gas bubbles that acted as a bubble curtain and reflected ASDIC impulses to produce a false target. The container trapped hydrogen and floated, with a crude spring valve to maintain buoyancy to keep it at a constant depth.
Later decoys, such as Sieglinde, were motorised and could deploy their false target away from the host submarine, increasing safety.
Torpedo decoys[edit]
Decoys were also used by surface ships to decoy the developing acoustic torpedoes. These were usually towed behind the host.
Example decoys[edit]
Bubble decoys[edit]
Reflective bubble targets
Hammer and explosive decoys[edit]
These were intended to swamp the listening device with noise
- Siegmund
Signature decoys[edit]
Towed decoys[edit]
- Foxer, a British towed decoy to decoy acoustic torpedoes away from surface ships. Also used by the US as FXR and the Canadians as CAT.
- T-Mk 6 Fanfare, US development of Foxer
References[edit]
- ^ Gannon, Robert (2009). Hellions of the Deep. Penn State Press. pp. 132–133. ISBN 978-0271038407.
External links[edit]
- "Sonar decoys". uboataces.com.
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