HedgeHog weapons

[vanjast]

I've read an interesting book which states that the hedgehog mortars were set to automatically explode at one of two depths, 90 feet or 150 feet. There's no mention of contact detonation.. maybe this was an earlier type of Hog, as in some pics the hogs definitely have pins on them. In the book it says that the total force of all the hogs going off at the same time was equivalent to a lot more DCs, and if a sub was within the circle it would suffer badly. I'll scan the pages and book details ?

[Sailor Steve]

Direct reference confirmation would help, because this is the first I've ever heard such a thing. John Campbell's Naval Weapons Of World War Two definitely mentions contact-only, and the weapons themselves were only 17.8cm across, so any kind of depth-setting device would be difficult if not impossible.

As for an earlier type, I'm not sure how it could have that name since "Hedgehog" was a direct reference to that particular weapon's similarity to the animal's quills.

[vanjast]

I'll put all the stuff together... you know a person is talking genuine when he mentions 'words' of the trade in the correct places...!

[Sailor Steve]

Going by the old saying "The more I learn, the less I know", I figure I've learned enough by now to know I don't know anything. Based on what I've read, I believe certain things. If information comes to light indicating those things might be wrong, I'm ready to see that I can learn something new. Even the best sources can miss things. :sunny:

[vanjast]

Interesting equipment extracts from book.

https://www.dropbox.com/s/acz2jwttc1l65fg/BookCover.jpg

https://www.dropbox.com/s/w8unmqvk0sn4648/Book_NewSensorPg1.jpg

https://www.dropbox.com/s/1tf46gr8j057g8a/Book_NewSensorPg2.jpg

https://www.dropbox.com/s/ttwczr6ruvadxym/Book_NewSensorPg3.jpg

https://www.dropbox.com/s/cn38327ra216v5e/Book_NewSensorPg4.jpg

https://www.dropbox.com/s/089eym00ygs3cw6/Book_NewSensorPg5.jpg

https://www.dropbox.com/s/o8wl08pcfitshlt/Book_NewSensorPg6.jpg

https://www.dropbox.com/s/1dvkp9tvlgbpj6y/Book_NewSensorPg7.jpg

https://www.dropbox.com/s/eij7yw23pe3c3ey/Book_NewSensorPg8.jpg

https://www.dropbox.com/s/lnh8qbp4m6cyduz/Book_NewSensorPg9.jpg

https://www.dropbox.com/s/3rn2o7wk178igy3/Book_NewSensorPg10.jpg

[Sailor Steve]

While interesting, I still question its accuracy. I can find no other source that agrees with either the two depth settings or the statement that it used depth settings at all. I tried looking up Martin T. Gilbert, thinking he might be Martin Gilbert the well-known historian, but he's not, and the only reference I've been able to find was his authorship of this book. I looked up the book on Amazon, and the only review there gives it two stars (out of five), and mentions "some innacuracies", but he doesn't say what they are and he gives nothing that would show his qualification to make such a statement, so his "review" is not helpful at all.

If I had to make a choice at this point I would stick with Campbell's research credentials, but then I'm probably biased too.

[edit] I looked up "hedgehog" at www.uboat.net (http://www.uboat.net), and this (http://uboat.net/allies/technical/hedgehogs.htm) is their article. Their sole listed source also seems to be an interesting book.
http://uboat.net/books/item/2349

[Jimbuna]

I'm of the understanding there is a mix up between the workings of the Hedgehog and the Depth Charge here.

My understanding has always been that the attacking ship could only verify if a hit had been achieved when an explosion was witnessed because of the contact detonator....otherwise there would always be twenty four explosions at the end of a launch.

The bullets used percussion fuse, so that only direct hits this explosive detonated.

When unsuccessful attacks, the water was not dispersed and the use of further attacks ASDIC not hindered

http://www.desertwar.net/hedgehog-weapon.html

[vanjast]

Ja.. I found the 2 depth settings on the hogs a bit odd.. but it does make sense to have them explode all at once around a sub.. maybe it was the original idea that never took shape.

[Marcello]

Ja.. I found the 2 depth settings on the hogs a bit odd.. but it does make sense to have them explode all at once around a sub.. maybe it was the original idea that never took shape.

That was the working principle of the squid, using six charges exploding around the sub. The projectiles however had a mass in the same class of depth charges and a time fuze. I have not been able to see a mechanism that would allow setting an exploding depth in the standard hedgehog round. It seems to me that at most it would be possible to incorporate a single self destruct depth.

[Friedl9te]

but it does make sense to have them explode all at once around a sub.

Does it ?

A DC Mark VII contains 130kg explosives and the distance for a severe damage of a sub is 12-18 meters, 6-8 meters for an imediate loss of the sub.
A single Hedgehog contains 14kg of explosives and wouldnt have led to a severe damage to a sub, except it exploded very close or even in contact with the hull. If there were only two dephts to set, the sub would be too far away from the explosion in most cases.

If the other hedgehogs could have detected the pressure wave of the explosion of the one that got in contact to the hull and then activate/explode themselves, that would have made sense, in my opinion. But I think, they never had this ability.

[vanjast]

Well if you think of it..
One hog hits the sub and the rest 'explode in sympathy'...
The hogs that hit the sub naturaly would do the most damage, while the others going off together would shake thing up quiet a bit, possibly doing more internal damage.

There are conflicting stories about the hedgehog, but as one person at UBoat net pointed out.. That explosives were unreliable in WW2...
Maybe the hog was not supposed to explode in sympathy - they just did so anyway, according to Bob Whinney and others. Sometimes they did not go off ??

It would be great to get the proper facts, from design and experience.
:up:

[Jimbuna]

These links as well as the memories of my late father who experienced them say it all for me:

The benefits of this type of weapon is that the position of the U-boat is more accurately known and the projectiles do not explode unless they hit something meaning that ASDIC contact is not lost due to massive underwater explosions unless the attack is successful.

http://uboat.net/allies/technical/hedgehogs.htm

The missiles were contact fuzed, thus only detonating when hitting a submerged object, such as a submarine.

http://www.ussslater.org/tour/weapons/hedgehog/hedgehog.html

This weapon had the disadvantage of requiring a 'hit' before it could detonate.

http://www.naval-history.net/xGM-Tech-Anti-submarine%20Weapons.htm

[Aktungbby]

I believe the confusion stems from confusing the projectile hedgehog with the projectile 'squid mortar' a three war head firing device often mounted doubly with a triangle pattern and a specific depth setting Above and below the sub's estimated position from both aft mounted weapons. The hedgehog was a contact weapon, the Squid was not. Both weapon systems were to obviate a destroyer or escort's "blind spot" on sonar as it approached a submerged U-boat.

[Sailor Steve]

Actually it muddies it quite a bit. If you're going to copypasta an entire article it would be nice to provide a link to the article itself and erase some of the bizarre links going to random useless places. Wiki is a better source than a lot of people give it credit for, and this article is a very good one, but leaving links to such diverse subjects as "British", "mortar" and "fuse" add nothing to the discussion and show lazy scholarship.

[ridgewayranger]

Hi, Hav'n't been on the site for a while and have just seen a load of rubbish about Hedgehog. I was a TASI and taught these things to many young classes. I can categorically state that HH never had preset depths, it was an impact projectile with an inertia fuze. If one scored a hit it would explode and countermine the whole 24 salvo because they were close together, about 30 feet between projectiles. If no hits were obtained there was no water disturbance to blot out sonar. They did of course explode on hitting the bottom. They were fired in pairs by a ripple firing switch, to prevent the mounting from being driven down through the deck if all were fired simultaneously.

[Jimbuna]

Hi, Hav'n't been on the site for a while and have just seen a load of rubbish about Hedgehog. I was a TASI and taught these things to many young classes. I can categorically state that HH never had preset depths, it was an impact projectile with an inertia fuze. If one scored a hit it would explode and countermine the whole 24 salvo because they were close together, about 30 feet between projectiles. If no hits were obtained there was no water disturbance to blot out sonar. They did of course explode on hitting the bottom. They were fired in pairs by a ripple firing switch, to prevent the mounting from being driven down through the deck if all were fired simultaneously.

Not wishing to appear stupid but which parts do you consider to be rubbish?

I am genuinely interested.

[Aktungbby]

DONE http://en.wikipedia.org/wiki/Squid_(weapon (http://en.wikipedia.org/wiki/Squid_(weapon) but leaving links to such diverse subjects as "British", "mortar" and "fuse" add nothing to the discussion and show lazy scholarship.

Indeed! I find your argument supremely compelling on those three diverse items items you have mentioned; and apologize profusely for my lazy scholarship. Lazy scholarship in the world's foremost gaming forum is intolerable and should not be condoned.

[Sailor Steve]

DONE http://en.wikipedia.org/wiki/Squid_(weapon (http://en.wikipedia.org/wiki/Squid_(weapon)

Indeed! I find your argument supremely compelling on those three diverse items items you have mentioned; and apologize profusely for my lazy scholarship. Lazy scholarship in the world's foremost gaming forum is intolerable and should not be condoned.
Nor should going back and rewriting your posts over and over again until you get your digs in. In case no one else has noticed, the post I originally took you to task for has been edited nine times. You appear to be playing games, and it won't be tolerated for much longer.

[CaptBones]

Yeah, late to the party as usual, but I think Aktungbby got it right; the author of the book cited by the OP was most likely confusing HH with Squid, and/or recalling the use of both of them together in a tactical situation (no such thing as 100% reliable memory!).

During my Midshipman days, there were still a number of older DEs in service with HH and/or Squid mortars installed and "old hands" teaching at the ASW schools who had first-hand experience with using both HH and Squid in real-world ASW. If I could find my class notes, I'm sure they would agree with the evidence here and elsewhere that HH was strictly contact-fused and Squid was strictly depth-setting fused. Using them together would be as close to "ideal" as you'd likely get back in those "good old days".

Anyway, I'm glad everyone calmed down finally...none of us really appears to have enough hair to be spending any time pulling it out over things such as WWII ASW trivia...do we?:D

[vanjast]

Yeah, late to the party as usual, but I think Aktungbby got it right; the author of the book cited by the OP was most likely confusing HH with Squid,
Highly unlikely... This person was a qualified Officer Electrical Engineer, who installed these systems and then went to sea with them.

..and I can vouch as an electrical engineer.. you DON'T forget systems and how they work.. no matter what your age..:arrgh!:

[Sailor Steve]

Possibly he installed the firing systems, but did he work on the hedgehog or squid themselves? Was he a qualified expert in how the detonators work? I ask because he disagrees with every other source we've found so far. He could be right and they could all be wrong, but it seems unlikely to me.

[vanjast]

Having worked on naval systems myself, which are not isolated from other disciplines.. everyone learns about each others 'responsibilities' and systems.
All share the systems knowledge..

I'd imagine that expertise is isolated but closely knitted, but not so isolated, so much as to exclude general knowledge.

:up:

[Sailor Steve]

I understand that. I also understand that you are dead set on this book being the gospel truth, no matter what other authorities say. That's fine, but it seems there's nothing more to discuss.

As I said at the beginning, I'll take Campbell over anybody else, especially when supported by every other source, save this one.

[vanjast]

I understand that. I also understand that you are dead set on this book being the gospel truth, no matter what other authorities say.
Not so... It is possible that the first Hogs might have been preset depths or did he get the wrong info. But he certainly did not mix the hog up with the Squid or DCs.. it's quiet clear in those pages. He summarises the DCs and squid fairly well, why not the Hog.

The original question was about the preset depths, which I mentioned, sounded rather odd, and could there have been a very early Hog system that originally used preset depths, but was changed to contact detonation shortly afterwards - this is the history we know of.

I'm quiet OK with the HedgeHog as it stands..
:03:

[vanjast]

Sometimes you 'gotta have faith' :D

Two designs for the fuse, which became armed as the projectile passed through the water and fired on contact, were developed simultaneously. The successful one was mainly the work of Lieutenant Commander H. D. Lucas on the staff of the Chief Superintendent of Armament Design, assisted by D.M.W.D. From here the story is told by Gerald Pawle: http://www.mikekemble.com/ww2/hedgehog.html#hedgehog

http://www.goodeveca.net/CFGoodeve/cfg_bio.html

Maybe this is what Mr. Gilbert was on about - the arming depth.

[Sailor Steve]

The article as related by both sites are identical - one of them copies the other, so having two links is redundant. The second link appears to be the original. Also it would be nice if you quoted the exact lines you wanted to direct us to. Just linking the whole article, which is mainly about Mr. Goodeve's entire life and career, is not helpful.

While interesting, I don't see any mention of depth settings of any kind.

Two designs for the fuse, which became armed as the projectile passed through the water and fired on contact, were developed simultaneously.
So it armed itself when it entered the water, but was only ever a contact fuse. I don't see anything that supports your contention. Still, I might have missed it.

[Aktungbby]

:agree:

[vanjast]

I'm not saying that the Hog never had a contact fuse, this is written all over the history... It was about 'finding' this odd thing he'd written about the hedgehog..

Written history misses a lot of things and usually focuses on the main events and in that quoted section, looks like what could have been a source of misunderstanding
The hog had to arm at some depth... were these settable or just set at one depth by default (most likely this and as shallow as possible)
I had to find info on the hedgehog development 'program' to clarify this... Just accepting things is not good enough and those links (one a short autobiography and the other both having the same info) sort of helps clear things up a bit.

That's if you can trust the internet that is... :03: