"Keith Willshaw" wrote in message ...
"Eunometic" wrote in message
om...


The German Type XXI u-boat had the an array sonar that was unusually
accurate and capable of ranging (and thereby plotting and evading
attacking ships) german hydrophones were based on passive arrays
electronicaly processed and distributed around the hull and were far
more accurate and sensitive than allied ones. Sonar ranging both
active and passive allowed the Type XXI to attack without use of
periscope.


In theory, in practise the vast majority of type XXI boats
built were of such poor quality that they were unfit for
service and only one ever went on patrol.

This of course delayed entry into service untill the defectice
building was remediated. However they formed the backbone of not only
the post war German navy but were extensively used by others.

Some XXI's were for example a long time in use
by:

France: U 2518 ("Roland Morillot", decomm. 1967)
Great Britain: U 2502, 2506, 2511, 3017, 3514
USSR: U 2529, 3035, 3041, 3515
USA: U 2513, 3008


The list of ships sunk by this type follows

Start of List
End of List

Not for lack of capabillity:

U 2511 (Korvettenkapitaen Adalbert SCHNEE) left Bergen at the end of
April
'45. On the next day she met a British Sub Hunter Group -- and was
detected
and attacked. But her sonar enabled her to plot the British movements
and
she escaped.

On May 4th she met a British group, the cruiser HMS Norfolk with her
escort.
They had been on the usual U-Boat alert, but didn't find U 2511.
Incidently
U 2511 was in a good position. Assuming, that Adalbert Schnee didn't
get his
oakleafs for nothing, he couldn't have missed a cruiser at 700m
distance,
but the BDU had already ordered to cease fire. Back in Bergen, the
Norfolk's officers didn't believe, they had been targeted, until, they
read the log book of U 2511.

Apart from their superb sonar, great speed, range and diving depth
these u-boats had secondary creeper drive opperated via 12 v belts
that made them essentialy undetectable at speeds of up to 6 knots.





Keith