U-Boats Surfaced To Charge While Type 271 Radar Picked Periscopes At Night

U-Boats Surfaced To Charge While Type 271 Radar Picked Periscopes At Night
North Atlantic, May twenty-fourth, nineteen forty-three, zero six hundred hours, and Grand Admiral Karl Dönitz sat in his headquarters at the Hotel am Steinplatz in Berlin, staring at the message he was about to transmit to every U-boat commander still alive in the Atlantic, knowing this order would mark the end of everything they had fought for since nineteen thirty-nine, the admission that his wolfpacks had been defeated not by better seamanship or superior tactics but by a technology his technical experts had assured him was impossible, a radar that could see in darkness what human eyes could never detect, and the numbers on his desk told the story in blood—forty-two U-boats destroyed in a single month, one thousand eight hundred and thirty-two of his best submariners dead, twenty-five percent of his entire operational strength annihilated, all because British escort corvettes carried a device in a perspex lantern that could detect a periscope at nine hundred yards in pitch darkness while his boats sat on the surface charging their batteries, completely unaware they were being watched.
The message went out at zero six fifteen hours: withdraw from the North Atlantic convoy routes immediately, and in that moment, as Dönitz would later write in his memoirs, "We had lost the Battle of the Atlantic," though what he didn't know, what he couldn't know, was that the technology defeating him had first been tested on a small Flower-class corvette named HMS Orchis in the Firth of Clyde on March twenty-fifth, nineteen forty-one, when a prototype device designated Type two seven one had tracked a submerged submarine at four thousand yards and detected its periscope at nine hundred yards, ranges that British radar engineers at the Telecommunications Research Establishment had achieved using a cavity magnetron operating at ten centimeters wavelength, a frequency band that German radar warning receivers couldn't detect, creating a blind spot that would prove fatal to the U-boat arm.
The British operator sitting at his Type two seven one console aboard HMS Orchis that March morning in nineteen forty-one had watched the green trace on his A-scope display, adjusting the gain control as the target submarine raised its periscope for a practice attack run, and there it was—a sharp spike at nine hundred yards, clear as daylight though the Scottish morning was thick with mist, the ten-centimeter waves penetrating the sea clutter that would have swallowed the return on older metric radars, and he called out the bearing to the bridge, "Contact bearing zero four five, range nine hundred yards, probable periscope," not knowing he was witnessing the first successful demonstration of a technology that would sink forty-two U-boats in a single month two years later.