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- Silent Hunter III (https://www.subsim.com/radioroom/forumdisplay.php?f=182)

- - Hedgehog (https://www.subsim.com/radioroom/showthread.php?t=219828)

Problem is that even in XXI you still get no report of a hedgehog attack, unlike for depth charges, so you have to guess when to start to run. But if you start to push the pedal to the metal too often and for too long you will collect a pack of escorts on your back. And that is not pretty, even with latest Bold countermeasures, Alberich and a lot of juice in the battery. Once you find yourself with 4-5 DEs trying to get you things get dicey even in a wunderwaffen.

One would have heard the projectiles hitting the water. The non-report must be a huge bug, right?

No uboat hit with spigot bomb ever survived

I'm not sure how much a passive listener on a uboat could pick up in time to permit his skipper to evade in a hedgehog 'encirclement'...practically none. Here is a fact I did not know or even consider beforehand: "The contact-fused bombs were filled with 32 pounds of Torpex – if one bomb hit the target it exploded and the rest of the pattern detonated too, greatly increasing the likelihood of a successful attack compared with depth charges." ALSO noteworthy as to evasion times: " Missiles were fired in pairs with an interval of either 0.1 or 0.2 seconds between pairs. The order was such that the missiles with the highest trajectories were fired first while those with the flattest trajectories were fired last. This allowed all missiles to hit the water at about the same time. Reload time was 3 minutes. When aimed to impact at 200 yards (180 m) from the firing ship, it took about 17 seconds from the time the missiles were fired until they sank to a depth of 200 feet (61 m) and 34 seconds to reach a depth of 600 feet (183 m). "HASTA LA VIS........:dead:" (no verbal funker to kaluen to helmsman command sequence can conceivably cope with 17-34 seconds-cut in half from the splashpoint!) Some of the advantages of this weapon were that 1) They only exploded if they hit something, which meant that the firing ship could more quickly make follow-on attacks if the previous attack was unsuccessful; 2) as unsuccessful attacks did not disturb the water, which meant that ASDIC/Sonar performance was not affected; and 3) the projectiles had a higher sinking rate than conventional depth charges which again sped up the time that it took to make follow-on attacks. " Required viewing: https://www.youtube.com/watch?v=5kAj9syecU0 Bottom Line: to the 'expensive problem' on the battlefield-uboats-there came a cheap...and very efficient and lethal solution.

You're right about that. The hydrophone would be of little use in detecting the pattern. Maybe one projectile but no more. How about the launch sound then? How much noise would the launching of the projectiles make? Would that have been heard in the boat - only 200 meters away but with a mass of water between, and the sounds of the engines covering some noise?

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Originally Posted by sublynx (Post 2309330)

Probably not much, I can't find footage with actual sound but I suspect it might not be much louder than a Bofors letting loose. In a combat situation with ASDIC hammering away, multiple engine noises...

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Originally Posted by Marcello (Post 2309348)

Probably not much louder than the K and Y gun depth charge launchers which were in routine use as well.

Doenitz, U-666, and a watery bourn!

YIPES! U-666, My avatar!! lost with all hands 2/10/44 mysteriously, but- in a postwar assessment, to HMS Fencer depthcharges- was participating in Wolfpack IGEL: http://www.cnrs-scrn.org/northern_mariner/vol05/tnm_5_1_33-43.pdf at the time...actually one of Doenitz's bigger failures. Igel in German is Hedgehog! No wonder I'm intrigued by the topic!:hmmm: :shifty: :dead:

Some notes on ASW weapons here. Squid looks a lot more deadly in practice - the bit I don't like is

Quote:

Ships with one mounting produced a triangular pattern with 120 foot sides and those with two mountings an additional pattern at a lower depth - hopefully with the target submarine between the two layers.

Squid was fitted to about 70 ships during WW2. Hedgehog was probably carried by hundreds towards the end of the war.

And the reason they had two layers to catch the sub in between is that with the blast radius and water pressure would crush the U-boat like a beer can. Certain kill. And shots that hit the boat from underneath do more damage because that's where the greatest concentration of valves, plugs, and flanges can be found. Very sinister...

Quote:

Originally Posted by Aktungbby (Post 2309328)

Great video.:/\\k: