Alberich

[Friedl9te]

Saw a documentation about "Alberich" yesterday. Alberich was a rubber coating of U-480 and some other boats. U-480 managed to sink 4 ships in the British Canal without beeing dicovered and this happened 1944 !!! No chance at all to find them if they were absolutely silent. Does anybody know if this is implemented correctly in GWX ?

For those who understand german.
http://www.youtube.com/watch?v=mkZFXNbkz2w
http://www.youtube.com/watch?v=5GCQ8Ava16M
http://www.youtube.com/watch?v=zarO5W1nR3M
http://www.youtube.com/watch?v=etKvM-mgae4
http://www.youtube.com/watch?v=OwuclvdJlkw

[flag4]

http://www.subsim.com/radioroom/showthread.php?t=155616


have a look here Friedl9te...it is available, but i have never got this far !


...also, have seen the documentary you have linked up. i saw it in english on Sky - History Channel...V.Good!!

[Friedl9te]

It was said "Supposedly it will reduce chance of detection by 10%", but this is not true.
Making absolutely no noise the UBoat with the Alberich was totally invisible for the ASDIC. The first stealth Uboat. I think this is not implemented correctly.

[irish1958]

It was said "Supposedly it will reduce chance of detection by 10%", but this is not true.
Making absolutely no noise the UBoat with the Alberich was totally invisible for the ASDIC. The first stealth Uboat. I think this is not implemented correctly.
This is easily implemented; disable the sensors for sonar, but leave alone those for visual and radar, which accounted for most of the U-boat kills later in the war, anyhow.
I did some extensive testing on Alberich sometime back and found that it is indeed helpful and made evasion a bit easier. If I recall correctly, it was with GWX 2.1

[Mittelwaechter]

As far as I know the Alberich was useful in shallow depths because the coating was compressed only moderately. In deep dives the effect of the coating was equalised in comparison to an uncoated U-boat.
And they had severe problems in fixing the coat on the hull, resulting in loose parts and increased sound and ASDIC signature.

[irish1958]

Mittelwaechter
Interesting.

[Brag]

As far as I know the Alberich was useful in shallow depths because the coating was compressed only moderately. In deep dives the effect of the coating was equalised in comparison to an uncoated U-boat.
And they had severe problems in fixing the coat on the hull, resulting in loose parts and increased sound and ASDIC signature.

If that's the case, the 10% gives us a sort of realistic result

[flakmonkey]

oddly enough, the same stuff alberich was made from (polyisobutene, also called oppanol) is found in chewing gum....hmmmm, just thought id share that useless fact:yeah:

[Friedl9te]

alberich was made from (polyisobutene, also called oppanol)

Sorry, that is not correct. The stuff Isobuten-Isopren-Kautschuk (Butylkautschuk) was used for Alberich and not Oppanol.

They are similar but have different propertys as well.

Oppanol ---> http://de.wikipedia.org/wiki/Polyisobutylen

Alberich & Chewing gum ---> http://de.wikipedia.org/wiki/Butylkautschuk

[flakmonkey]

Sorry, i stand corrected. this was my source (i guess i shouldnt beleive everything i read!):

"Greatly interested for reduction of the sonar echo of their U-boats, the Germans experimented with sound absorbing synthetic rubber-like laminated coating of about 4mm thickness, intended for efficiency reduction of Allied active sonar devices, which also possessed significant sound absorbing properties.

The material was called Oppanol, an transparent, versatile polymer (in essence form of polyisobutene, even today highly renowned chemical with applications assortment varying from chewing gum, adhesive plasters and double-glazing sealants through to cable insulation, roofing sealants and protective coatings applied to pipelines), impervious to water and gases, resistant to chemicals, physiologically harmless and with elevated adhesive properties. Renowned German company BASF patented a synthetization process for polyisobutene in 1931, and the product was later called Oppanol after the Ludwigshafen suburb of Oppau, where it was developed and produced. However, another seven years of research and development work were needed before it could be produced on an industrial scale. The first Oppanol plant went into operation in 1938, but in those times its military potentials still were completely overlooked.

This laminated material was secured to the outer hull with different adhesives. Although no conclusive tests were performed, Germans claimed that the sonar echo reflection of a U-boat equipped with Alberich coating was reduced by some 15 percent, although absorption varied with depth, temperatue and salinity. In addition, this maetrial also acted as a sound dampener, containing the U-boat’s own engine noise. Basically, the thin two-ply synthetic coating slightly oscillated while the submarine moved through the water, thus providing partial absorption and phase-shifting of reflected sonar impulses.

Although the principle was a completely scientifically sound one, numerous problems were encountered with the adhesion capacity of the special glue (ethylene-vinyl), which was not strong enough to keep the rubber panels in place. This resulted in the sheets being partially washed off, or flapped in the wake of the ocean current, causing hydrodynamic resistance and additional noise. Over time wave action and salt made the rubber panels come lose and actually created more noise than a boat that did not have the coating. It was also discovered that coating is decreasing the speed of the vessel by 1.5 knots. A further deficiency was the fact that adequate treating of the submarine hull was a highly time consuming and very laborious task.

Further research into more reliable adhesives was conducted, but up to the end of the war only a few U-boats had received this treatment. These coatings were intensively investigated in the US after the WW2, but they were not employed due to constantly present adhesion complexity.

Nevertheless, it is highly intriguing that in the early fifties the Soviet Union began providing its own Malyutka-class (Малютка = little one) of coastal submarines with these anti-sonar and anti-echoic coatings. They successfully evolved into real multi-purpose coatings, capable not only to reduce echo-footprint of the submarine, but also to absorb noise of the internal machinery. Important distinction, however, is that these solutions were feasible in application on double-hall submarines only, where coatings could be placed upon multiple sufaces."

[Friedl9te]

The two different substances PIB and PII are misleadingly sometimes both called Oppanol, etc. but should not be mixed up.

PIB (Poly-Iso-Butene) is, depending on the grade of polymerisation, an oil for lubrication, or a liquid with high viscosity and alway has a tendency to creep, even if it is highly polymerised.

IIR (Isobuten-Isopren-Kautschuk) is used for every purpose that was covered with natural rubber before. Tyres, thermal and accoustic insulation, sealants, membranes, gloves, etc. It was produced in Germany since 1943

SBR (Styrol-Butadien-Kautschuk) was another sythetic rubber well known as BUNA and produced in Germany since 1939.

I dont know exactly if IIR or SBR was used for Alberich, but I think it was IIR because of the better accoustic insulating properties.

[Jimbuna]

I believe the original question was "Does anybody know if this is implemented correctly in GWX ?"

The answer is.....nobody can give a definitive answer base on RL historically accurate figures, but I can say that under gaming conditions it was given a 10% more effective chance of making the U-boat harder to detect. This was intended to compliment the fact that it was an upgrade and therefore an improvement or aid.

[irish1958]

I believe the original question was "Does anybody know if this is implemented correctly in GWX ?"

The answer is.....nobody can give a definitive answer base on RL historically accurate figures, but I can say that under gaming conditions it was given a 10% more effective chance of making the U-boat harder to detect. This was intended to compliment the fact that it was an upgrade and therefore an improvement or aid.

And, in fact, on testing this proved to be so.

[FIREWALL]

I believe the original question was "Does anybody know if this is implemented correctly in GWX ?"

The answer is.....nobody can give a definitive answer base on RL historically accurate figures, but I can say that under gaming conditions it was given a 10% more effective chance of making the U-boat harder to detect. This was intended to compliment the fact that it was an upgrade and therefore an improvement or aid.

Jim... Now you know why I pester "you" with questions. :haha:

I could care less what it's made of. Interested more on if it will protect my arse. :DL

That bubble gum ain't cheap. :p2:

[Lt.Fillipidis]

Hmm...
If the actual coating that was 4mm thick could reduce detection by 10% then, in theory, an 8mm coating would double the effect and a 40mm coating would cease all noise. Plus, reducing the blast force by depth charges.

Is this correct or i should go get some math sessions? :arrgh!:

[FIREWALL]

How many coated uboots survived the war without being sunk ?


I'll stick to , go deep, silent running, 1knt and 10 degrees port then starboard thank you.

Has worked everytime so far.

[Jimbuna]

Jim... Now you know why I pester "you" with questions. :haha:

I could care less what it's made of. Interested more on if it will protect my arse. :DL

That bubble gum ain't cheap. :p2:

Well for what it's worth....I use it when it becomes available.

Provided I survive that long of course :DL

[Jimbuna]

Hmm...
If the actual coating that was 4mm thick could reduce detection by 10% then, in theory, an 8mm coating would double the effect and a 40mm coating would cease all noise. Plus, reducing the blast force by depth charges.

Is this correct or i should go get some math sessions? :arrgh!:

It doesn't work that way ingame I'm afraid.

Where in the files is 4mm used as a direct influence or indicator that the 10% efficiency saving is dependant on thickness?

The sensor parameters were tweaked to give an equivelant effect of a 10% reduction in the chances of detection under certain variable conditions.

Eg: Under test conditions an escort detects the U-boat at 400 metres....after file adjustments and under as near identical conditions as possible, the U-boat isn't detected until the escort is within approximately 350 metres.

[irish1958]

Again, after 3-5/1943 Hedgehogs, aircraft carriers, better and better radar, lots more ASW vessels, more bases including the Azores which closed the gap in the Atlantic sea lanes, intense pressure from superior officers,including Churchill and Roosevelt to stop the losses, reasoned tactics applied by experienced and talented naval officers, Admiral King getting his head out of his ass and finally understanding that the U-boats were a real problem and not just an irritation made sonar less and less important. The subs could be completely invisible to sonar and the losses would be about the same.
This, of course, would change with the nuclear subs that never needed to surface.

[Lt.Fillipidis]

It doesn't work that way ingame I'm afraid.

Where in the files is 4mm used as a direct influence or indicator that the 10% efficiency saving is dependant on thickness?

The sensor parameters were tweaked to give an equivelant effect of a 10% reduction in the chances of detection under certain variable conditions.

Eg: Under test conditions an escort detects the U-boat at 400 metres....after file adjustments and under as near identical conditions as possible, the U-boat isn't detected until the escort is within approximately 350 metres.

Im talking about real life, Jimbuna.
Theoreticaly, the thicker the coating the less sound is reflected back to the sonar/made by uboat. But how about in practice?

[NoLine]

Alberich's purpose wasn't to make sub more silent, but to reduce or eliminate the return of the ASDIC signal

cheers
Noline

[Mittelwaechter]

AFAIR - all 11 coated U-Boats were sunk - but none with the help of ASDIC!

[Jimbuna]

Im talking about real life, Jimbuna.
Theoreticaly, the thicker the coating the less sound is reflected back to the sonar/made by uboat. But how about in practice?

Ah right...my mistake :doh:

[Friedl9te]

AFAIR - all 11 coated U-Boats were sunk - but none with the help of ASDIC!

U480 was not sunk by human action. It sunk after having contact with a seamine in a secret minefield.

It was never located by ASDIC !

[irish1958]

U480 was not sunk by human action. It sunk after having contact with a seamine in a secret minefield.

It was never located by ASDIC !

You are right; the stuff worked. The point is that it didn't make any difference for almost all U-boats. Something else killed them, and they had no way to escape.

[Jimbuna]

U480 was not sunk by human action. It sunk after having contact with a seamine in a secret minefield.

It was never located by ASDIC !

That is dependant on what reference source you believe and in your case U-boat.net for one:

http://uboat.net/boats/u480.htm

I have in my possession two other reference books which put her sinking down to depth charge attack by the RN frigates HMS Duckworth and Rowley of the 3rd Escort Group, shortly after she had attacked convoy BTC.78 and sank the Oriskany.

The hunt lasted 6 hours on 24-02-45 position (4955Nx0608W) 11 miles south-west of Lands End, sufficient wreckage was recovered for a 'kill' to be claimed.

An interesting one is this :hmmm:

[Friedl9te]

Well, the fate of many boats ist not yet clear. 64 years after the end of the war, history of some boats must be rewritten.
For instance U869
http://de.wikipedia.org/wiki/U_869

After the sinking of the ships in the canal by U480, tons of depth charges were thrown but these droppings were not targeted in any way.
This tactic was well known and should lead the commander to panic induced reactions, so to reveal his true position.
They knew that there had to be a boat but they did not know where it was.
In the documentation, which is worth seeing, the wrecked boat can be seen.
The damaga pattern looks more like direct detonation of a big mine close to the hull. To hit a boat with depth charges in that way must be a lucky punch. Whereas hedgehogs or similar weapons would never had destroyed the structure of a boat so severely.

[Jimbuna]

U-869 is the latest classic example on the subject.

I find it kinda interesting how different reference works fail to agree or contradict one another after over 60 years.

It makes one wonder how many mistakes have been made....we'll probably never find out.

[FIREWALL]

You are right; the stuff worked. The point is that it didn't make any difference for almost all U-boats. Something else killed them, and they had no way to escape.

The ones that survived had good Kpllt's.

That's why I don't use it .

[Ford Prefect]

There's only really one way to find out as to the effectiveness of the stuff. You need to restore a U boat, coat it up, put it out to sea and test it using period sonar. There's too much contradictory evidence in the history books on which to base any theory.

[U2222]

There's only really one way to find out as to the effectiveness of the stuff. You need to restore a U boat, coat it up, put it out to sea and test it using period sonar. There's too much contradictory evidence in the history books on which to base any theory.

Surely in this day and age it could easily be replicated in a lab?
I knew they should not have cut up U534!:nope:

[Zilch]

Yeah...I'm sure there's a rationale for slicing that thing up. Even though it's better on the surface where people can appreciate it in some form, as opposed to the ocean floor, seeing it cut up like a sausage still makes me retch a little.

[Ford Prefect]

Surely in this day and age it could easily be replicated in a lab?
I knew they should not have cut up U534!:nope:

Possibly, but where's the fun in that? Surely having a working Uboat taking to the seas is a fun idea? I'd wager a fair number of folks on here would pay to have a ride on one.

[U2222]

Possibly, but where's the fun in that? Surely having a working Uboat taking to the seas is a fun idea? I'd wager a fair number of folks on here would pay to have a ride on one.

Yes, count me in.
Why should David Jason have all the fun.

[Ford Prefect]

Yes, count me in.
Why should David Jason have all the fun.

I thought that would sway you.