Bold (a term derived from
kobold
A kobold (occasionally cobold) is a mythical sprite. Having spread into Europe with various spellings including "goblin" and "hobgoblin", and later taking root and stemming from Germanic mythology, the concept survived into modern times in G ...
) was a
German
German(s) may refer to:
* Germany (of or related to)
**Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ger ...
sonar decoy
A sonar decoy is a device for decoying sonar. Most are released from submarines to act as a false target.
Submarine decoys
The first submarine decoys were the German Bold fitted to U-boats of World War II. These were a pellet of calcium hydri ...
, used by
U-boat
U-boats were naval submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare ro ...
s during the
Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
from 1942 onwards. It consisted of a metal canister about in diameter filled with
calcium hydride. It was launched by an ejector system
colloquial
Colloquialism (), also called colloquial language, everyday language or general parlance, is the linguistic style used for casual (informal) communication. It is the most common functional style of speech, the idiom normally employed in convers ...
ly referred to as ''Pillenwerfer'' (English: "
pill thrower").
When mixed with
seawater
Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appr ...
, 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 . The device lasted 20 to 25 minutes.
The
Royal Navy
The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by Kingdom of England, English and Kingdom of Scotland, Scottish kings from the early medieval period, the first major maritime engagements were foug ...
called it SBT (Submarine Bubble Target).
See also
*
Sieglinde (decoy)
Sieglinde was a sonar decoy used during the Second World War by German U-boats. ''Sieglinde'' was installed in chambers on the sides of the U-boat. It could be ejected to a considerable distance from the boat when attempting to hide from a seek ...
External links
Sonar decoys at uboataces.com
Sonar decoys
Weapons countermeasures
Sonar
U-boats
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