May 1943 - U-Boat Aces Had 3 Weeks Before Radar Made Atlantic Crossings A Death Sentence

The morning of May seventh, nineteen forty-three. Korvettenkapitän Herbert Schultze stood in the conning tower of U-forty-eight, scanning the horizon through Zeiss binoculars. The Atlantic stretched empty in every direction. No smoke trails. No masts. No aircraft. Just endless gray water under overcast skies. Schultze had been hunting convoys for four years. He'd sunk twenty-six Allied merchant ships totaling over one hundred and eighty thousand tons. He wore the Knight's Cross with Oak Leaves. He was one of Germany's most decorated submarine commanders. And for the first time in his career, he was afraid.
Not of depth charges or destroyers or the brutal mathematics of convoy warfare. Schultze feared something he couldn't see, couldn't hear, couldn't detect until it was too late. Three weeks earlier, the rules of Atlantic combat had changed in ways that made no sense. Ships that should have been blind were finding submarines with impossible accuracy. Aircraft were appearing without warning from Metox radar receivers that had worked perfectly for eighteen months. Escorts were coordinating attacks with precision that suggested they could track submerged submarines through methods German intelligence couldn't identify.
Something fundamental had shifted. Schultze didn't know what. Nobody did. But the casualty reports told a story more terrifying than any depth charge attack. In April, fifteen U-boats had been lost. That was higher than normal, concerning but not catastrophic. In the first week of May alone, another fifteen submarines had been destroyed. The loss rate had doubled overnight. Experienced commanders were disappearing. Boats that should have returned to Lorient or Saint-Nazaire simply never arrived. Radio contact ceased. Search aircraft found nothing. Entire crews vanished into the Atlantic without explanation.
Admiral Karl Dönitz, commanding U-boat operations from headquarters in Paris, had ordered every available submarine to concentrate against convoy ONS-five in late April. He'd assembled wolf packs Star and Fink, comprising forty-three U-boats total. It was one of the largest concentrations of submarines ever deployed against a single convoy. The battle for ONS-five had opened on April twenty-eighth when U-six-fifty spotted the merchant ships four hundred nautical miles south of Greenland. Dönitz expected a massacre. Forty-three submarines against forty-three merchant ships escorted by just seven destroyers and nine corvettes.
Instead, it became a disaster. The convoy lost thirteen merchant ships over six days of continuous attacks. But the U-boats lost six submarines sunk outright and seven more damaged so severely they had to abort their patrols. Thirteen percent of the attacking force destroyed. Another sixteen percent crippled. In exchange for sinking ships the Allies could replace within weeks from American shipyards now producing merchant vessels faster than Germany could sink them.