Bold (decoy)
Bold (also called Bolde, a term derived from kobold) was a German sonar decoy, used by U-boats during the Second World War from 1942 onwards. It consisted of a metal canister about 10 cm (3.9 in) in diameter filled with calcium hydride. It was launched by an ejector system colloquially referred to as Pillenwerfer (English: "pill thrower"). When mixed with seawater, the calcium hydride produced large quantities of hydrogen which bubbled out of the container, creating a false sonar target. A valve opened and closed, holding the device at a depth of about 30 m (98 ft). The device lasted 20 to 25 minutes. It replicated the echo of an Asdic-sonar submarine contact.[1]
The Royal Navy called it SBT (Submarine Bubble Target).
See also
[edit]References
[edit]- ^ Morgan, Daniel; Taylor, Bruce (2011). U-Boat Attack Logs: A Complete Record of Warship Sinkings from Original Sources 1939–1945. Seaforth Publishing. pp. xi. ISBN 978-1-84832-118-2.
External links
[edit]
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.
Cover photo is available under {{::mainImage.info.license.name || 'Unknown'}} license.
Cover photo is available under {{::mainImage.info.license.name || 'Unknown'}} license.
Credit:
(see original file).
