On Wed, 17 Mar 2010 16:31:00 -0400, Peter Skelton
wrote:

On Wed, 17 Mar 2010 07:27:50 -0700 (PDT), Chris
wrote:

On Mar 17, 7:38*am, Jim Wilkins wrote:

In the presence of U-Boote how would British subs communicate that
they were friendly to attacking British destroyers?

They wouldn't be able to. However, it is very unlikely that the
British destroyers would be worrying that much about U-boats. Their
best defense against U-boats would be speed: by moving fast (which
they will want to do anyway to avoid all those Luftwaffe planes, to
find and bring to battle the KM forces, and even to tip over the
invasion barges with their bow waves) they won't give submerged
submarines much of a chance to get into position: unless the submarine
is already in the correct position they won't be able to engage.

The KM invasion forces, on the other hand, will be tied to the 3-4
knot invasion barges, so there will be a lot of slow, tempting targets
for the RN submarines.

They'll have to surface and use their guns. Not much of the
invasion fleet was big enough to torpedo. The RN did not muster
subs in or near the channel, they had better use for them
elsewhere.

Peter Skelton

Wouldn't it take a particularly stupid admiral to try and use subs as
an invasion barge escort?

Also, while barges were a critical lift, there were also a fair number
of larger, coastal trade vessels that would have to be pressed into
service to carry the heavy stuff, including supplies of fuel. These
would have made fine targets for RN subs.

The U-Boat force would not be messing around with barges in the
Channel. They'd be setting up to intercept the Home Fleet as it came
south to "welcome" the invasion force.

Remember, too, the old saw: Amatuers study tactics; professionals
study logistics. There is no way the KM could have protected the sea
lift necessary to make any invasion possible.

Of course we see these things with the aid of 20/20 hindsight. At the
time I suspect there was more "fog of war" involved in decision
making.