The principle of firing projectiles forwards, instead of dropping depth charges over the stern, was considered viable, despite the failure of the Fairlie.

The propelling charge was part of the main weapon and worked against a rod (the spigot) set in the baseplate which fitted inside a tubular tail of the 'bomb'.

The adaptation of the bombard for naval use was made in partnership with MIR(c) under Major Millis Jefferis, who had taken Blacker's design and brought it into use with the Army.

The weapon fires a salvo of 24 bombs in an arc, aimed to land in a circular or elliptical area about 100 feet (30 m) in diameter at a fixed point about 250 yards (230 m) directly ahead of the attacking ship.

The system was developed to solve the problem of the target submarine disappearing from the attacking ship's ASDIC when closer than the sonar's minimum range.

The spigots were angled so the projectiles would land in a circular pattern with a diameter of 130 ft (40 m), about 200 yd (180 m) ahead of the ship's position.

[9] By the end of the war, statistics showed that on average, one in every five attacks made by Hedgehog resulted in a kill (compared with fewer than one in eighty with depth charges).

[3] In response to this new deadly threat to its U-boats, the Kriegsmarine brought forward its programme of acoustic torpedoes in 1943, beginning with the Falke.

These new "homing" acoustic torpedoes could be employed effectively without the use of a periscope, providing submarines a better chance to remain undetected and evade counterattack.

Initially it was used as a single weapon, but when this failed to be successful, it was upgraded to the "double squid" that consisted of two launchers placed in parallel.

[17] Weapons derived from the Hedgehog have been largely phased out from Western navies in favor of homing torpedoes, and in Russia and allied states like India by anti-submarine rocket launchers like the RBU-6000.