After Germany declared war on the United States in December 1941, Rear Admiral Karl Donitz launched Operation Paukenschlag -- Operation Drumbeat -- sending U-boats to prowl the American East Coast. The Outer Banks of North Carolina became the prime hunting ground for a simple reason of geography: the continental shelf is narrowest here, allowing submarines to lurk in deep water just offshore while merchant ships passed close to land. Allied vessels were almost comically vulnerable. No convoys ran along the East Coast for the first half of 1942. Ships sailed with their lights on, without zigzagging, silhouetted against the shore by the glow of coastal settlements and lighthouses. The Germans called this period the Second Happy Time. For the men aboard the merchant ships, it was anything but.

The toll was staggering. On the night of January 23, 1942, U-66 under Robert-Richard Zapp spotted the British tanker Empire Gem and the American ore carrier Venore off Diamond Shoals. A spread of torpedoes struck Empire Gem on the starboard side and she immediately burned and sank. Additional torpedoes found the Venore. Fifty-five of fifty-seven men on Empire Gem died, along with seventeen from the Venore. On March 26, the tanker Dixie Arrow, carrying crude oil from Texas City to New Jersey, took three torpedoes from U-71 off Cape Hatteras and broke in two. Able Seaman Oscar Chappell turned the burning ship into the wind to give trapped crewmen on the bow a chance to escape, and was killed by the flames for his trouble. Eleven of the thirty-three man crew perished.

Not every victim was American. The 443-ton British trawler Bedfordshire was deployed from Morehead City to hunt a U-boat near Ocracoke Island on May 10, 1942. Captain Lieutenant Gunther Krech of U-558 shadowed the trawler through the night. At 5:40 the next morning, a torpedo struck Bedfordshire and she sank with all thirty-seven hands. Two bodies washed ashore and were buried by the Americans on Ocracoke, creating a small British cemetery that still stands. Weeks later, when the British trawler Kingston Ceylonite struck a mine off Virginia Beach and more bodies drifted to Ocracoke, they were interred alongside the men of Bedfordshire. That quiet graveyard on a Carolina island remains a piece of sovereign British soil, maintained by the U.S. Coast Guard and visited each year on Commonwealth memorial occasions.

The Allies eventually struck back. On the night of April 13, 1942, the destroyer USS Roper detected U-85 on radar within sight of Bodie Island Lighthouse. The submarine fired a stern torpedo and opened up with its deck gun, but the Roper evaded everything, closed to 300 yards, and raked U-85 with gunfire before dropping eleven depth charges. All forty-six German crew members died. Some were found wearing civilian clothing with American currency and identification cards, suggesting the submarine had been landing agents on the mainland. On May 9, the Coast Guard cutter Icarus caught U-352 off Cape Lookout. Lieutenant Maurice D. Jester maneuvered his ship and dropped seven depth charges, forcing the U-boat to surface, where the Americans opened fire until the German crew abandoned ship. Jester received the Navy Cross. German casualties in Torpedo Alley totaled 100 dead and forty captured. The U-boat campaign was ultimately defeated by the convoy system, belatedly implemented in mid-1942.

The seabed off the Outer Banks is a ship graveyard unlike any other in American waters. The wrecks of Empire Gem, Dixie Arrow, Bedfordshire, U-85, U-352, and dozens of others lie scattered across the continental shelf, some in waters shallow enough for recreational divers. The hatch of U-85 is displayed at Cape Hatteras Lighthouse, and its Enigma machine resides at the Graveyard of the Atlantic Museum in Hatteras village. In all, German submarines sank roughly 400 ships with 5,000 deaths across the waters around North America during the war. The concentration of loss off the Outer Banks -- 80 to over 100 vessels in a single stretch of coastline -- remains a sobering reminder that World War II reached American shores in ways that are often forgotten.