On Mar 17, 7:42*am, "William Black"
wrote:
"Jim Wilkins" wrote in message
...
Safe zones.

Your submarines operate only in areas where you tell people not to shoot at
submarines.
William Black

In other words, not where the U-Boote might be defending the invasion
convoy. OTOH the Germans who survived to write their books didn't
attack when the convoy escorts were nearby.

British submarines:
http://www.mikekemble.com/ww2/britsubs.html

jsw