Hedgehog ASW weapon

[Blackie]

The hedgehog was a rocket propelled depth bomb with a contact fuze and it carried a rather small but effective charge. Launched from beds either fore or aft on asw vessels they created a pattern designed to "detect" subs. If one went off it meant a sub had been hit and then the ship would attack with depth charge cans, which were set to go off at a given depth. Hogs could kill alone but ashcans were "make sure" measure. Hedgehog was not a mine.

[Tiornu]

Hedgehog was a spigot mortar system, not a rocket system. You may be thinking of Mousetrap.

[Blackie]

No Tiornu, I'm thinking of hedgehog, the system I studied some 30 odd years ago when I was a budding Torpedoman.
I will wiave to your

spigot mortar

desciption. I used the word 'rocket' very loosely. The propelling charge did no more than throw the bomb in the air where it would hopefully not fall back on deck.
I never saw the system in operation but studied it and the device in school.

[Tiornu]

Fair enough. You definitely wouldn't have been studying Mousetrap in the 70's, as it was not very successful.

[phylo_roadking]

It was actually a development of the Blacker Bombard spigot mortar a variation on the WWI unsuccessful Grenatenwerfer 15 and 16. Originally intended for the Home Guard as an anti-tank weapon - its bulk, inaccuracy, loading procedure, flimsy construction, and a HUGE percentage of dud rounds - it was very unpopular; but Blacker as well as developing the idea into the PIAT, made the original Bombard's inaccuracy a virtue and constructed a multi-barrel area bombardment system!