Stealth technology

[Edwin]

Testing during the war and after showed that the Alberich tiles only reduced the active sonar signal (by absorbtion and redirection) by about 15%. Nice, but ultimately probably not worth the effort and expense.

I've always wondered why the 15% percent figure keeps getting quoted as there's no real source behind it. The German tests came up as follows (from Cold War, Hot Science Applied):

"Meyer and Oberst had undertaken theoretical, laboratory and full-sized trials to develop a coating that could be applied to U-boat hulls which would reduce the reflectivity of the hull to impinging sonar pulses. Their experiments demonstrated that the parameters of concern were the thickness of the hull plating and whether air or water was behind it. On this basis they developed a two-ply rubber sheet 4 mm thick, with the inner ply perforated by 2- and 5-mm holes which determined the resonant nature of the system. Although the theory proved useful, the material was developed in an empirical fashion involving the testing of some tens of thousands of different materials. Trials were carried out with a full-sized U-boat in the Skagerrak late in the war which seemed to show the efficacy of the system, with a claimed reduction in reflectivity of 20 per cent. As this was accompanied by a reduction in detection range of 60 per cent, these claims were treated sceptically by the report's translators."

60 percent is certainly a dramatic and worthwhile reduction IMO (even if it only applies to certain depths or acoustic conditions)

[mookiemookie]

Originally Posted by Edwin

I've always wondered why the 15% percent figure keeps getting quoted as there's no real source behind it. The German tests came up as follows (from Cold War, Hot Science Applied):

"Meyer and Oberst had undertaken theoretical, laboratory and full-sized trials to develop a coating that could be applied to U-boat hulls which would reduce the reflectivity of the hull to impinging sonar pulses. Their experiments demonstrated that the parameters of concern were the thickness of the hull plating and whether air or water was behind it. On this basis they developed a two-ply rubber sheet 4 mm thick, with the inner ply perforated by 2- and 5-mm holes which determined the resonant nature of the system. Although the theory proved useful, the material was developed in an empirical fashion involving the testing of some tens of thousands of different materials. Trials were carried out with a full-sized U-boat in the Skagerrak late in the war which seemed to show the efficacy of the system, with a claimed reduction in reflectivity of 20 per cent. As this was accompanied by a reduction in detection range of 60 per cent, these claims were treated sceptically by the report's translators."

60 percent is certainly a dramatic and worthwhile reduction IMO (even if it only applies to certain depths or acoustic conditions)

But from what I've read about the system is that the adhesive was flawed. Once the rubber coating was applied, the boat would submerge and the adhesive would fail in places, causing the rubber tiles to flap in the current, actually increasing the noise signature of the boat. This is why the idea was good in theory but flawed in practice.

[Kaleun_Endrass]

Originally Posted by mookiemookie

But from what I've read about the system is that the adhesive was flawed. Once the rubber coating was applied, the boat would submerge and the adhesive would fail in places, causing the rubber tiles to flap in the current, actually increasing the noise signature of the boat. This is why the idea was good in theory but flawed in practice.

I read somewhere that this was the reason why the first coating tested in early 1940 was withdrawn and and second approch to introduce a rubber coating was made in late 1944.

[java`s revenge]

I think that the modders of the great mod gwx3 has looked too much to das boot.

Nowadays a uboat is still difficult to track. I do remember an incident nearby the swedish coast. The swedish navy was searching for a russian sub but it was
never been tracked.

You can`t tell me that as in gwx3 that you were so easily to be found by
destroyers.

1 point, laying on the seabed with your sub. In real life you were unfindable.
You know what happens when you try it in sh3.

[sav112]

All I can say to on the subject of the resin to attach the Coating was that in the TV programme they discussed that U480 had to go in to get it repaired when the Captain bottomed the boat and it moved across the seabed under Ocean currents.

But the guy who survived said the boat Coating was strong after they got there act together in first blasting the hull in dry-dock with metal ball Barings to give a an ultra smooth and clean surface then painted with bonding coat.

But I’ll tell what that was crystal clear that when they dived on the boat the Coating was fantastically intact after being on the sea bed for over 60 years.