The Americans lost 15 MILLION tons of shipping (including cargo tonnage) from late 1941 to late 1944 simply because of the deadly efficiency of the U-boats against lightly-armed merchant shipping, which was the primary delivery method from the U.S. for War materiel.
There are countless thousands of new items of war equipment on the bottom of the Atlantic - tanks, guns, trucks, Caterpillar tractors, jeeps, huge numbers of aircraft engines and spares - everything that Armies needed to operate.
It took the Americans far too long to find ways to effectively counter the U-boat menace. For the U-boats, destroying merchant shipping was like a shooting ducks on a pond, and the merchantmen losses were appalling.
The U-boats sank a total of 2828 Allied ships, and the vast majority of them either carried new war materiel, or were oil tankers.
Rommel lost his major advantage and the opportunity to wipe the Allies out in Africa, simply because the Germans did not understand the importance of logistics and the need to keep up the required level of vital supplies and spares for mechanised forces.
Rommels tanks ran out of fuel because the Germans weren't organised enough to keep up the level of fuel that Rommel required for his advance.
No doubt the Desert Fox was furious over the lack of support that saw his advance stalled for such a basic requirement.
To add to the irony, he was operating in the area where the some of the worlds greatest supplies of oil were located and produced!