Jon, W3JT wrote:
"Folks unfamiliar with WW II history must also note that the US had
almost no sub forces in the Atlantic since Germany had only a very small
surface Navy amd no coastal or open shipping."

The emphasis should be on the "almost"!
Germamy began the war with 3 formidable "pocket battleships" as I
recall. There were American submarines in the Atlantic. Headquarters are
at New London, CT. My brother was a WW-2 U.S. Navy submarine officer.
His boat was stationed in the Atlantic operating from the U.S. Virgin
Islands. He managed a leave home by snagging rides on Catalina flying
boats conducting anti-submarine patrols in the Atlantic. He observed
real anti-submarine actions while a passenger aboard the Catalinas. My
brother was assigned to a new ship from its keel laying. He took it
through the Panama Canal to the Pacific where after several missions it
became a craft on permanent patrol as the result of enemy action with no
known surviors. His family misses him.

Best regards, Richard Harrison, KB5WZI