Bold (decoy)

The Bold was a device that was designed to deceive the enemy ASDIC localization for German submarines. It should be the submarine hunter feign a decoy under water, in the "shadow", the submarine should escape the enemy pursuit.

The first development was called " liar ". The device was not out of the experimental stage. The development was stopped, as was shown in experiments with S- systems that air bubbles produced an echo in the water. The news means test command (NPC ) then developed another device, the " Tarnbold " that could create air bubbles in the water. Later the device was simply called " Bold".

A Bold consisted of a cylindrical wire cage about 10 cm in diameter with a swimming cap, filled with a mixture of coarse ground calcium hydride, which was coated with water-soluble paint. This could produce in shallow water for half an hour of hydrogen gas bubbles that reflected the sound waves emitted by the opponent like a submarine. Three to five jokers sufficient to produce in shallow water a stronger echo than a submarine in the bow or stern location to location transmitter.

After trials in the Bay of Biscay and during a patrol in 1941, in which an enemy submarine hunter was successfully deceived, it was decided to equip the submarines with it. For an ejector was designed and built from 1942 on all front- submarines.

Thus, six cages are ejected under water. More could be recharged.

This Bold lock was called by the crew casually " pill launcher ". Since the effectiveness decreased at greater depths, 4 was still working alongside the Bold 1944 used for a more effective Bold 5, which was also launched in depths of 200 m.

The Bold had proved very successful until the war ended.