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Cpt_Walrus
06-18-2005, 03:23 PM
I would like to know the following:

How did the captains and crew of the allied warships in WW2 knew when they damaged or killed a u-boat that was submerged?

twistedpretzel
06-18-2005, 03:32 PM
Pieces would come up? They could hear the hull of the sub exploding and popping from the destruction through their hydraphone?

StgShultz
06-18-2005, 03:32 PM
One way is to listen and you hear the missle explode on the sub or the sound it makes when it hits the deck or the sound of it imploding as it sinks too deep. Or lastly all the floatsum that floats to the surface including bodies.

Ratek
06-18-2005, 03:56 PM
If the sub was catastrophically damaged, it would in fact implode and make loud sounds, even make a similar splash as the Akula does in The Hunt for Red October, if it was shallow.
That was relatively 'easy' to detect.

If the sub only suffered deadly damage to the engines and diveplanes or similar (thus it would slowly sink) it couldn't be detected. But silence from a sub that had just been noisy was often taken to be a kill. Thus the claimed kills ended up being quite a bit higher than actual losses. So when a story tells of a destroyer blasting 6 subs in one day, be careful about it. But there were good destroyer aces.

Caseck73
06-18-2005, 05:11 PM
When a sub took damage and partially flooded, as it began it's final descent and was crushed, the sound of the metal hull shrieking as hull and bulheads collapsed were very distinctive sounds over hydrophone.

Additionally, sometimes when a sub was hit, it would detonate it's torpedoes, resulting in a brilliant flash from underneath the water, and a loud secondary explosion. (As reported by SEAWOLF sinking U-47.)

Also note, a depth charge damaging the stern section of a sub would usually result in a warping of the screw drive shafts, which also made a distinctive noise as the propeller shaft would rub each revolution, metal against metal.

stinkhammer6
06-18-2005, 08:00 PM
Other than the normal implosion sounds you would hear, if it was shallow enough youd hear the sub hit the coral or sand below, explosions from inside of the sub were heard, besides the guys screaming as water was rushing in the bilge from the oil reserve would float to the surface creating a slick, any wood from fruit crates would surface, life jackets, half drank bottles of wine that still had a cork in them, things of that nature.
Some sub commanders, providing the hull was well in tact would actually crash dive to the bottom to create all kinds of noise simulating the destruction of a sub, they would take damage of course but nothing like what a depth charge would do, usuall bow torpedo room took damage and flooding for the most part but then would shut down and do a quick quiet and lay there dormant, purge some oil from their bilge and wait for it to surface to create the oil slick I mentioned to simulate a kill, if the destroyers bought the bluff, they could ping all they want and still detect the sub but had no way of knowing if it was truely destroyed, but having heard the noise then seeing the oil slick, it usually paid off and after a lengthy time of waiting just to be sure, they would surface to periscope depth, if all was clear, they cleaned their pants and got the heck out of there. At certain depths they could even shoot debris out of a torpedo tube to simulate total destruction.

W.Irving
06-19-2005, 02:10 AM
Ejecting debris thru the tubes... wouldn't that give them away? First an immense blowing sound, then bits of rubbish conveniently surfaces. http://forums.ubi.com/groupee_common/emoticons/icon_razz.gif

Also, could they really operate the tubes at such a depth? I can't open the tubes below ~20 metres.

Well, a XXI could I suppose..

dannytherat
06-19-2005, 04:54 AM
In the book "Three Corvettes", Nicholas Monsarrat (author of "The Cruel Sea" and an officer on Flower Class corvettes during the Second World War) said that although oil and debris would be a reasonable indicator that a submerged U-Boat had been sunk, the most definite indicator would be floating bodies or parts of bodies.

V-MAN1981
06-19-2005, 05:08 AM
Originally posted by Ratek:
If the sub was catastrophically damaged, it would in fact implode and make loud sounds, even make a similar splash as the Akula does in The Hunt for Red October, if it was shallow.
That was relatively 'easy' to detect.

If the sub only suffered deadly damage to the engines and diveplanes or similar (thus it would slowly sink) it couldn't be detected. But silence from a sub that had just been noisy was often taken to be a kill. Thus the claimed kills ended up being quite a bit higher than actual losses. So when a story tells of a destroyer blasting 6 subs in one day, be careful about it. But there were good destroyer aces.

It was an Alfa not an Akula

VF-17_Jolly
06-19-2005, 05:18 AM
Originally posted by W.Irving:
Ejecting debris thru the tubes... wouldn't that give them away? First an immense blowing sound, then bits of rubbish conveniently surfaces. http://forums.ubi.com/groupee_common/emoticons/icon_razz.gif

Also, could they really operate the tubes at such a depth? I can't open the tubes below ~20 metres.

Well, a XXI could I suppose..

Flooding a tube and letting debris out at any depth is not impossible but emptying the tube of water would take a lot of compressed air due to the external pressure, i believe the the ammount of compressed air used to lauch a torpedo becomes greater the deeper one goes and because we can only fire torpedos that is why we cannot use the tubes below a certain depth.Unfortunatly debris release is not modeled in SHIII (although i think it was modelled in SHII)

Ratek
06-19-2005, 06:44 AM
Originally posted by V-MAN1981:It was an Alfa not an Akula

Rats! They look alike and have similar names and it is a long time ago I last watched the movie... Yes I'm excused. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

W.Irving
06-19-2005, 07:54 AM
So it's not a matter of the internal torpedo tube hatches being weaker than the external doors, thus making them unable to withstand the water pressure exerted on them when the outer doors are open?

Aren't the tubes normally 'blown' (empty) when there is no torpedo in them?
In that case, the crew could just put all their rubbish in a tube, close inner door, open outer, and hope the contents will find the way out.

VF-17_Jolly
06-19-2005, 10:05 AM
Since i am not sure how the plumbing on a sub work i thought this might make good reading. Its for US Navy fleet subs but the priciples are the same.

how torpedo tube work (http://www.maritime.org/fleetsub/tubes/index.htm)

W.Irving
06-19-2005, 11:01 AM
Interesting reading.

It says US torpedos could be launched at depths down to 200ft/67 metres. I haven't had the chance to upgrade to anything bigger than a VII, but surely the IX could launch torpedos beyond 20m?
The VII has a pneumatic system operating up to 120 bar (or if it was 200... hum, whatever).
That manual specifies the impulse pressure at 200ft to be 600psi - or 41 bar... http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

stinkhammer6
06-20-2005, 09:30 AM
I seemed to have started something with the debris thing. The original SH had that option and I do miss it. According to some sailors I know from the US submariners of ww2 their toilet closet (literally) was ran on compressed air as well, they called it the Flush and Duck. If the boat was at the right angle and moving at the right speed it would reverse to shot of air that was used to launch what ever it was you left in the toilet back at you instead of out of the sub. I bet the new guy on the sub had a pretty awful job of being the flush boy.

Psychfilm
06-20-2005, 10:39 AM
In U-boats offshore: When Hitler Struck America by Edwin Palmer Hoyt, he talked about a time when American Naval Ships caught what they thought was a "U-Boat" off the shore of North America and depth charged it for three days. Oil, Debris and even a body floated to the surface before the realized they had been attacking a recent ship wreck... Doh! http://forums.ubi.com/images/smilies/1072.gif

VF-17_Jolly
06-20-2005, 12:42 PM
Originally posted by stinkhammer6:
I seemed to have started something with the debris thing. The original SH had that option and I do miss it. According to some sailors I know from the US submariners of ww2 their toilet closet (literally) was ran on compressed air as well, they called it the Flush and Duck. If the boat was at the right angle and moving at the right speed it would reverse to shot of air that was used to launch what ever it was you left in the toilet back at you instead of out of the sub. I bet the new guy on the sub had a pretty awful job of being the flush boy.

Taken from:
HM Submarine Museum (http://www.rnsubmus.co.uk/)

Just to add to the toilet humour

The heads and wash places are along one side of the passageway leading into the Engine Room. Although there were two fresh-water distillers they used too much electric power to run continuously and water was always short on patrol; sometimes it had to be rationed and was generally limited to about one gallon for each man per day for all purposes including cooking and washing-up. There was certainly no water to spare for bathing and men rinsed the worst dirt off their hands in a communal bucket before having a more thorough wash in one of the basins. The heads (W.C.€s) were rather more civilised than in earlier submarines where the contents had to be blown direct to sea when €œpulling the plug€; in the old days this sometimes resulted in an occurrence known as €œgetting your own back€ when sea pressure overcame blowing pressure. Alliance had a sewage tank into which all the heads drained and this was blown periodically, usually at night when there was no risk of the bubbles being seen on the surface.
http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

ShinyBaldy
06-20-2005, 12:53 PM
g debris out at any depth is not impossible but emptying the tube of water would take a lot of compressed air due to the external pressure, i believe the the ammount of compressed air used to lauch a torpedo becomes greater the deeper one goes and because we can only fire torpedos that is why we cannot use the tubes below a certain depth.Unfortunatly debris release is not modeled in SHIII (althou


FYI - the US navy is currently developing a diaphram pressuization system to fire torpedos... the previous system involves a lot of tanks, pumps, high pressure valves, etc...

the newly developed system uses a rubber diaphram... imagine a diaphram in the middle of a chamber.. both sides are filled with air... suck air away from one side and the diaphram will move to the direction of the vaccuum... this stores the kinetic energy into potential. When they release the valve to let air reenter - the motion pushes the air in the other chamber into the torpedo tube and launches the torpedo out.

Interesting system that apparently is smaller, lighter and quiter.

VF-17_Jolly
06-20-2005, 02:48 PM
Originally posted by ShinyBaldy:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">g debris out at any depth is not impossible but emptying the tube of water would take a lot of compressed air due to the external pressure, i believe the the ammount of compressed air used to lauch a torpedo becomes greater the deeper one goes and because we can only fire torpedos that is why we cannot use the tubes below a certain depth.Unfortunatly debris release is not modeled in SHIII (althou


FYI - the US navy is currently developing a diaphram pressuization system to fire torpedos... the previous system involves a lot of tanks, pumps, high pressure valves, etc...

the newly developed system uses a rubber diaphram... imagine a diaphram in the middle of a chamber.. both sides are filled with air... suck air away from one side and the diaphram will move to the direction of the vaccuum... this stores the kinetic energy into potential. When they release the valve to let air reenter - the motion pushes the air in the other chamber into the torpedo tube and launches the torpedo out.

Interesting system that apparently is smaller, lighter and quiter. </div></BLOCKQUOTE>

Very interesting but unfortunatly does not apply to 60 year old boats,but as You point out the system on these old boats involves tanks and high pressure air systems, but as the US boats of the time could launch torpedoes from as deep as 200ft why can`t we even open the bow doors on SHIII subs let alone fire a torpedo below i think 12-15m(can anyone correct me)
Unless U-boats had a much less powerfull compressed air system there should be no reason why it shouldn`t be included.
I have yet to find the same kind of technical info on U-boats as is available for US Navy boats of the same era

ShinyBaldy
06-20-2005, 03:22 PM
Originally posted by VF-17_Jolly:
Very interesting but unfortunatly does not apply to 60 year old boats,but as You point out the system on these old boats involves tanks and high pressure air systems, but as the US boats of the time could launch torpedoes from as deep as 200ft why can`t we even open the bow doors on SHIII subs let alone fire a torpedo below i think 12-15m(can anyone correct me)
Unless U-boats had a much less powerfull compressed air system there should be no reason why it shouldn`t be included.
I have yet to find the same kind of technical info on U-boats as is available for US Navy boats of the same era

The only plausiable explaination was 1) programming made the decision or 2) the pressure at 200ft is too great for the torpedo hatch to survive. I won't be suprised if the Uboats had a weaker compressed air system for their torpedo tubes. Remember - they are smaller boats. Who needs to fire a torpedo as deep as 200ft is beyond me anyway. They had no real targeting system until the homing torpedo and active sonar. Even that was a risky shot...

*shrug*

stinkhammer6
06-22-2005, 11:26 AM
Scenerio for you: You have been spotted by a destroyer and you submerge, all of your attempts to elude the ship have failed and its charges damaged you badly, you go deep trying to get away from the charges but they are homing in on your depth, you have 2 torpedo's left and half of your crew is fixing leaks, but one or two more near explosions will seal your crews fate, you are at 200m, you know the destroyer type, sonar states they are 400m to your starboard and in about 45 seconds they will be directly in front of you. Would you not like to plot a solution for a torpedo to attempt to take out the ship thats about to kill you? Setting your torpedo depth for 3m means it will launch then surface and stabilize at 3m, by the time it does this coming from 200m under water moving to a target a mere 400m away would give them little to no warning of a torpedo heading their way. Kind of like a bull shark spotting a baby seal trodding along above it and it swims up quickly from below. Element of suprise my friend.

cirdan
06-22-2005, 07:14 PM
Originally posted by W.Irving:
So it's not a matter of the internal torpedo tube hatches being weaker than the external doors, thus making them unable to withstand the water pressure exerted on them when the outer doors are open?

Aren't the tubes normally 'blown' (empty) when there is no torpedo in them?
In that case, the crew could just put all their rubbish in a tube, close inner door, open outer, and hope the contents will find the way out.

hehe
we used to keep the beer in the aft torp tubes. I can just imagine the look on the crews faces if we had to blow that all out into the oggin.
At one stage I was dragging the beer out of the tube when the crew shut the door on me(at 600 ft down). It took all my nerve not to break into a panic but I had the knowledge that I was fairly safe as I was in there with all the beer and of course they eventually let me out - with two cases of beer.

Cirdan

cirdan
06-22-2005, 07:21 PM
Originally posted by VF-17_Jolly:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by stinkhammer6:
I seemed to have started something with the debris thing. The original SH had that option and I do miss it. According to some sailors I know from the US submariners of ww2 their toilet closet (literally) was ran on compressed air as well, they called it the Flush and Duck. If the boat was at the right angle and moving at the right speed it would reverse to shot of air that was used to launch what ever it was you left in the toilet back at you instead of out of the sub. I bet the new guy on the sub had a pretty awful job of being the flush boy.

Taken from:
HM Submarine Museum (http://www.rnsubmus.co.uk/)

Just to add to the toilet humour

The heads and wash places are along one side of the passageway leading into the Engine Room. Although there were two fresh-water distillers they used too much electric power to run continuously and water was always short on patrol; sometimes it had to be rationed and was generally limited to about one gallon for each man per day for all purposes including cooking and washing-up. There was certainly no water to spare for bathing and men rinsed the worst dirt off their hands in a communal bucket before having a more thorough wash in one of the basins. The heads (W.C.€s) were rather more civilised than in earlier submarines where the contents had to be blown direct to sea when €œpulling the plug€; in the old days this sometimes resulted in an occurrence known as €œgetting your own back€ when sea pressure overcame blowing pressure. Alliance had a sewage tank into which all the heads drained and this was blown periodically, usually at night when there was no risk of the bubbles being seen on the surface.
http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

We could have salt water showers pretty much at any time and we had soap specifically for salt water. Most of the crew didn't bother as you would stinck of diesel and sweat ten minutes after a shower anyway so you just got used to it. I do remember a toilet blow-back that flooded the control room once. That was funny because I rarely had to work there and most of the officers and senior crew had to put up with it until they got a civilian crew in to clean it up but only after a week of it. The compartment under the control room used to gurgle with the sewerage down there like it was a troll groaning.

Cirdan

stinkhammer6
06-23-2005, 09:53 PM
Wasnt in the navy but on a few ships in my time while in the marines so I got a good idea of what goes on while on a ship. I got bored of sleeping all the time so I created the great spoon shortage, every time I went to chow, I grabbed two spoons, used one, kept one and stashed it with the others I snagged. After about a month complaints about missing spoons were rampant. Then eventually a reward was put out for anyone returning the missing spoons, smelling a trap I put the box of spoons next to the hatch of the berthing area and got out of there. Spoons returned, I created turmoil and humor for everyone else humor.