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.

[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]

Originally Posted by 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.

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]

Originally Posted by 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.

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

[Friedl9te]

Originally Posted by flakmonkey

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]

Originally Posted by 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.

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

[FIREWALL]

Originally Posted by 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.

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

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

That bubble gum ain't cheap.

[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?