On Mar 16, 11:40*pm, Bill Kambic wrote:
O...

People forget that the RN had subs in 1940, too. *If the Kriegsmarine
had tried an invasion they would have been as subject to attack as the
Allies were in '44 and without any significant anti-submarine
capability.....

In the presence of U-Boote how would British subs communicate that
they were friendly to attacking British destroyers? Many ships fired
at friendly aircraft that they could clearly see but not properly
identify.

jsw