A good read focusing on German submarine warfare early in WWII is ‘Operation Drumbeat’. The U.S. was totally unprepared for submarine warfare and a handful of German subs wreaked havoc up and down the east coast of the U.S. Shipments of oil were halted completely at one point due to the Germans sinking so many tankers.
That was a good book.
I saw the evidence of the U-boat attack on fuel barges... In the 1960’s on the south New Jersey Shore — just south of Atlantic City. The sand had these stripes of black and mom had us check our feet for “tar balls” before going into the house. This was from a sinking of a fuel barge off of Sea Isle City, NJ
some clippings
http://www.pressofatlanticcity.com/news/press/cape_may/how-a-german-submarine-attack-forever-changed-cape-may/article_10872806-2fb2-5907-abee-c07880ac94dd.html
http://whitedeercafe.blogspot.com/2011/12/rudolph-rudy-plappert-nazi-submariner.html
Even given the lack of US preparations, we lost a lot of ships and tankers unnecessarily in the first months of the war. US leaders refused to take basic precautions....
My father was in Florida at the time and he said they would go to the beach and watch the fires from the torpedoed tankers.
Southern railway and other roads had oil drag trains running up and down the coast for that very reason.Few picture exist because of wartime regulations photographing trains.The one I have seen was impressive with a string of 8000 gallon tank cars as far as you could see.