Hi,
I think you`re right on this,
last weekend I looked into my books,studied pictures of the late type VII-C`s,but found nothing.
I have seen this rubber mat only on type`s IX ,X,and the XXI............for now
.
The type XXIII I am working as we speek.
This is quote from the book''Uboowaffe,marine-kleinkampfverbande 1939-1945'' page54.
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It is 10 mm mat made of carbonyl steel and pernunbau(kind of rubber),whose surface resembled that of a waffle
and wich was able to absorb some 50% of the radar echo.Beginnig in September 1944,the ''waschmatte''
was used to wrap schnorkels heads,a modification found on some 100 U-boats by the end WWII.A different radar
countermeasure was fitted to schnorkels with a floater ball cutoff valve.A cilindrical shield from prof.J..Jaumann`s team,
called the ''leitwert-sumpf'',was proposed in early 1944.Constructedwith materials characteristic in electric condition,
the shield was covered with ''zelligelit'',a kind of plastic.Some 70mm thick,the shield produced a 65%radar echo reduction
for radar devices operating on a 9cm-long wave (even more satisfactory results were obtained during testing).
In view of such an outstanding performance,orders went out in mid 1944 to provide schnorkels ,as far as possible,oly with the
ball cutoff valve fitted with the ''leitwewrt-sumpfem''.Manufactured by the firm of IG-FARBEN,the first two shields were send
the yard at GW in early September 1944.Experiments were conducted with other materials absorbing radar waves.
Among available records are test of U-992,covered with a layer of wood,and U-680 and U-1209,
whose hulls were coated with glass wool.
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;)have a nice day.
my best regards,
Ron.
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