Developed during the First World War, depth charges remained the primary means of attacking submarines well into the Second, before being largely replaced by antisubmarine mortars and later missiles and torpedoes. Essentially large drums filled with explosives, depth charges were set off at a predetermined depth by special fuzes known as hydrostatic pistols.

0:00 Introduction
2:10 British Commonwealth Depth Charges of WWII
4:42 Hydrostatic Pistol Mk.VII** Introduction
6:06 Hydrostatic Pistol Mk.VII** Design and Operation
11:09 Hydrostatic Pistols Mk. XIV, XVI, XIX, and XX
13:29 Booster Placer/Extender Safety Mechanisms
15:15 US Depth Charges of WWII
16:30 US Hydrostatic Pistol Mk.6 Design and Operation
19:13 Outro


SOURCES:

http://michaelhiske.de/Allierte/USA/U...
https://maritime.org/doc/depthcharge6...
http://www.navweaps.com/Weapons/WAMBR...
https://www.bulletpicker.com/pdf/OP1...
http://www.maritimequest.com/library/...