List of British Asdic systems


was British version of sonar developed at the end of World War I based on the work of French physicist Paul Langevin and Russian engineer M. Constantin Chilowsky. The system was developed as a means to detect and locate submarines by their reflection of sound waves. By the start of World War II in 1939, most British destroyers and smaller vessels were fitted with it in a variety of different sets.
NameDate of IntroductionDomeNotes
Type 1121920Fitted to some s and small escorts like P and PC-class sloops
Type 1191930s
Type 121Tested 1931 in First production retractable domeFitted in D,, F, and G-class destroyers, some cruisers and the sloop
Type 122DetachableDesigned for trawlers and other auxiliaries with a turbo alternator
Type 1231934DetachableReplaced Type 122, designed for ships with a high-frequency motor alternator
Type 1241934RetractableC,,,,, and destroyers, some sloops and older destroyers. First system with a range recorder
Type 1271937As per Type 122Designed for sloops, but widely fitted in frigates and older destroyers. Electronics as per Type 123
Type 128Tested 1937 in Retractable, L, and s
Type 141?No dome, but some modified with British dome as Type 141AAmerican QCJ/QCL system in Lend-Lease s, modified with British range and bearing recorders
Type 144Trials in in 1941RetractableFirst set specifically intended for ahead-throwing weapons like Hedgehog
Type 1451942?DetachableLike Type 144, but intended for slower escorts
Type 147Sea trials aboard, May 1943?Designed to work with Squid
Q attachment1943NADepth-measuring set with 3° horizontal beam, modification to existing systems