Operation Drumbeat and the U-boat search for weak defences

How did Operation Drumbeat exploit weaknesses on the US east coast?

U-boats concentrated where escorts, convoys, and aircraft coverage were weakest, forcing the Allies to build costly defences before the threat could shift elsewhere.

Operation Drumbeat sent as many U-boats as possible into an area where American escort, convoy, and air arrangements were still thin. The method was to exploit a weakly defended zone, force the Allies to invest in escorts and infrastructure there, then threaten another area before those resources could be freely shifted. Returning to an earlier zone remained possible, so the Allies could not safely strip away the defences they had just created. The account treats this as an effective operational pattern while stressing that Dönitz executed an inherited doctrine rather than inventing it. A later comment asks whether his longer war and more advanced boats produced a less effective anti-shipping campaign than Germany achieved in the First World War.