"Keith Willshaw" wrote in message ...
"robert arndt" wrote in message
om...
Alan Minyard wrote in message
. ..
On 12 Oct 2003 08:14:41 -0700, (robert arndt) wrote:



A typo, Al. Relax. The line should have read YF-23. Second, the Type
XXI and XXIII U-boats that did employ the Alberich covering were
undetected, so were Type VIIs with the stealth schnorkel raised. The
radar absorbing paint became the basis for the type found on the
latter U-2s and yes, we did steal the entire radar defraction scheme
from a single Russian source.

Well now given that most Type XXI's never left the shipyard I suppose
its accurate to say they werent detected. U-Boats that dont make
operational patrols are rather hard to spot.

Despite the fact that the design was completed in June 1943
and the first boat launched in May 1944 only 2 type XXI's ever
went on war patrol IRC and the first such patrol was on 30th April 1945 !

The Germans never detected any DeHavilland Vampires on radar
either, does that make it a stealth aircraft do you think ?

Keith

U-2511 and U-3008 both went out on patrols with U-2511 passing
undetected under a HMS Suffolk and carrying out a mock attack (under
strict orders not to engage). He returned to base where 12 other Type
XXIs were fully ready for operation, with another 30 boats in the
stages of trial and training. One thousand more were under
construction. The Type XXIII had 6 operational patrols with none
detected and the last U-boat victory of two British freighters sunk
May 7, 1945. 59 more were launched by wars end. Over 900 Type XIIIs
were under construction.
After WW2, the USN heavily tested the Type XXI boat (as did the
British, French, and Russians) and found the design quite stealthy.
The Type XXI also was fitted with a silent V-belt drive system in
addition to the Alberich covering.
The problem with Alberich was not the covering itself but the adhesive
used to attach it to the boats. Early Alberich trials resulted in
seperated sheets of the material coming loose. This was later remedied
by the time the coating was applied to the Type XIII, U-4709 being the
first to recieve the new adhesive.
Had these boats been produced in number and launched a year earlier
the Allies would have had a tough time countering them.

Rob