It wasn’t the US Navy or Coast Guard that controlled America’s Atlantic waters in early 1942. It was the U-boats of Nazi Germany.

By Brian John Murphy

It was a bone-chilling January night for the men on the conning tower of U-123. The skipper, Lieutenant Captain Reinhard Hardegen, peered through high-powered Zeiss binoculars at a huge glow on the northwest horizon. Hardegen and his crew on the tower were the only German fighting men to see this sight since hostilities had begun a few weeks back, in December 1941—the lights of New York City. U-123 was the first German submarine—the first of many—to go hunting in American waters in World War II.

For seven months, from mid-January to early August 1942, German U-boats would take control of America’s East Coast waters, sinking freighters and oil and gasoline tankers—anything and everything steaming off the coast. Ship by sinking ship, the Nazis achieved a victory over the United States comparable to and even more devastating than the one the Japanese had enjoyed at Pearl Harbor a few weeks earlier. For months, the US Navy failed to come up with a plan to end the slaughter. Meanwhile, the American people were not being told how close they were to disaster.

When Adolf Hitler declared war on the United States in December 1941, U-boat skippers were more than ready to take the fight to American shores. In their view, President Franklin D. Roosevelt had already declared war on Germany long before; American warships accompanied convoys bound for Britain, and shots had been exchanged between German subs and American ships. The interference of the United States, hiding behind its nominal neutrality, crimped the aggressive style of U-boat skippers and was a thorn in the side of Admiral Karl Dönitz, commander of the U-boat arm of the navy.

Dönitz promptly began planning to take the conflict to the shores of the United States. He worked out a plan that called for scores of submarines to prowl the US coasts and virtually halt shipping there. But Berlin was reluctant to commit so many resources to the effort. Some subs would have to go to Norway to guard against a supposed British invasion. Still others were to be sent to the Mediterranean— which Dönitz regarded as a trap for U-boats—to support Lieutenant General Erwin Rommel’s Afrika Korps. In the end there were only nine subs available for operations in American waters and about five battle-ready ones that could set out at once. One of those subs was Hardegen’s U-123.

Given these paltry resources, Dönitz still expected to make quite an impression on the Americans. He labeled his effort Operation Drumbeat—Paukenschlag in German, a word with overtones of thunder and lightning—and assigned to it captains he was sure could stir up American waters.

In U-boat pens all over the coast of western France, German shore personnel and seagoing crews loaded torpedoes and 88mm shells into designated boats. Hardegen’s boat was a long-distance Type IX. Type IX boats would do most of the heavy lifting early in the operation; medium-sized Type VII boats would join in later.

Every inch of space on the cramped U-boats was given over to supplies. One toilet on U-123 was turned into a storage room, leaving only one other for the crew to use. Canned foods were stowed away deep, followed by fresh foods that would be eaten early in the cruise, much of it bearded with mold by the time it was served. The fuel bunkers were filled with diesel fuel, adding to the stench in the boat. Soon there was a medley of noxious odors and deadly fumes—combustion gasses from the diesel engines, body fluids and waste, rotting food, ripe sweat (bathing and shaving were discouraged), and stale air that had not managed to go through the primitive carbon-dioxide scrubbers.

As the men loaded the boats for what obviously would be a long cruise, excitement grew. In time the men were told that Dönitz had ordered that each boat in the force attack shipping in American waters on the same day—January 13, 1942.

The shocking attacks would target America’s Atlantic seaboard, which was under the care of Admiral Adolphus “Dolly” Andrews, commander of the Eastern Sea Frontier of the United States. Andrews needed destroyers to protect American coastal ship traffic, but they were not forthcoming from Commander in Chief of the US Navy Ernest King, who was sending some to the Pacific and most of the others to convoy duty on transatlantic runs. All Andrews had at his disposal were a few obsolete destroyers, yachts converted to antisubmarine service, and a few coast guard cutters. Neither Andrews nor King were ready to learn the lessons that had been so painfully taught to the Brits in their antisubmarine wars. As U-123 and her sister ships U-130, U-66, U-109, and U-125 approached the American coast undetected, King and Andrews were doing almost nothing to protect shipping along the eastern seaboard.

Hardegen started his drumbeat by sinking the large freighter Cyclops 300 miles east of Cape Cod, Massachusetts, on January 12, a day earlier than Dönitz had prescribed. The United States did not respond. Moving his boat on the surface, Hardegen continued on his way. The next day, he was surprised to find the Montauk Point Lighthouse, at the tip of Long Island, operating and providing him with a clear navigational fix. Hardegen lacked good charts for these waters, but he was agreeably surprised that cars, houses, streetlights, and advertising signs were lit all along the coast, giving him a good idea where he was at all times. He was about 60 miles off Montauk Point when he noticed an object looming ahead. He recalled that it was lit up from stem to stern, as though there were not a war on.

Hardegen maneuvered his sub for a good shot at the vessel, which he correctly made out to be a tanker. He did not bother diving. As soon as he had a firing solution from the ship’s calculator, he ordered torpedo tubes one and four flooded. Then he cried, “Los! Los!” (Fire! Fire!) Two “eels,” or torpedoes, shot into the water. One ran deep; the other ran true. About 50 seconds later, the crew of U-123 heard a loud explosion. From the conning tower, Hardegen saw a ball of flame rising about 75 feet above the target, followed by a mushroom of black smoke. The U-boat crewmen picked up a distress call on the 40-meter waveband: “Hit by torpedo….40 miles west of Nantucket Lightship…. Norness.”

Incredibly, the Norness remained afloat despite the fires on board. Hardegen maneuvered his boat to give tube five at the stern a shot. “Los!” The explosion came right under Norness’s bridge, silencing her radio room. Hardegen fired one more shot at the Norness, from tube two at the bow. After a 26-second run, the torpedo detonated and the Norness began to come apart. It sank straight down, the stern wedging into the sea bottom and leaving about 30 feet of the bow exposed above the waves. The Norness’s bow stood as a testament to Hardegen’s daring, operating in enemy seas so shallow, so close to shore.

Hardegen would bring the U-123 into even shallower waters on this cruise. He toyed with the idea of sailing right into New York Harbor, but decided that would be suicidal. His maps were sketchy at best. His position chart for the Ambrose lightship that marked the entrance to the harbor channel, for example, was a tourist map of the New York area. Hardegen still wanted to go in close to shore, however, and he headed for a light he took to be a buoy marker. At the last instant, the officers on the conning tower realized the light was on shore Just before the 123 grounded on the beach of Long Island, the engines were thrown into full reverse and the boat made a getaway.

Hardegen continued to sink Allied shipping on New York’s doorstep. On January 15, U-123 sent two eels into the Coimbra, a British tanker that broke and then exploded. “The effect was amazing, strong detonation, fire column reaching 200 meters and the whole sky was illuminated…,” Hardegen later wrote. “Quite a bonfire we leave behind for the Yankees as navigational help.” He did not bother submerging his boat after the attack, yet no US response came. No planes ventured out after the sub and no destroyers left for sorties. In fact, nothing stopped Hardegen from making another kill: the freighter San José. This latest victim was sent to the bottom in shallows 1,000 yards away from the coast guard base at Atlantic City, New Jersey, where an unarmed patrol craft that had been sent out to find the U-boat was having its engines repaired.

On January 18, Frigate Captain Richard Zapp and his U-66 got on the scoreboard off Cape Hatteras, North Carolina. Zapp positioned his boat in what was probably the busiest sea lane on the eastern seaboard and waited for prey. On his first predawn morning on station, opportunity came Zapp’s way in the form of a fully loaded oil tanker, the Allan Jackson, bearing more than 72,000 barrels of crude oil. Zapp stalked the tanker for four hours, then put two torpedoes into her. The tanker broke up and burned. U-66 spent a day submerged and then went hunting that night and found a Canadian passenger liner, the Lady Hawkins. Two torpedoes were enough to send her to the bottom. Of 300 passengers and crew, only 96 survived.

Hardegen and the U-123 were still busy. They were operating off Hatteras on the night of January 19, when they found a target—the City of Atlanta. Two eels sank the freighter, taking more than 40 men down with her. That same predawn morning, Hardegen’s boat spotted three more targets coming up over the northern horizon and sank one of them, the brightly lit freighter Ciltvaira. Against the advice of his officers, Hardegen sped after a second target and began firing on it with his 88mm deck gun. There was an eruption of fire when the gun found its target, the Malay, which ran for Norfolk, Virginia, and made it the next day, though hardly in one piece.

Hardegen and the crew of U-123 had given a virtuosic performance since their arrival in American waters. They had attacked eight ships and had sunk six of them without the Americans firing a single shot in response. On the way home, U-123 sank two more ships using only her deck gun. Hardegen would receive the Knight’s Cross of the Iron Cross for his feats.

Meanwhile, Zapp was not idle. Still off North Carolina’s Outer Banks, U-66 sank the freighter Olympic with two shots. In a double score on January 23, Zapp torpedoed the tanker Empire Gem, and three minutes later, the freighter Venore, which was laden with iron ore from Chile. Zapp sailed for home, having used up all his torpedoes.

By this time, other U-boats were also causing havoc along Admiral Andrews’s Eastern Sea Frontier. From January 11 to January 31, 1942, the boats of Dönitz’s operation attacked 40 ships and sent almost all of them to the bottom. These were the easiest pickings the U-boats had enjoyed since their first months against the British in 1939, which U-boat men had dubbed the “Happy Time.” Soon, the days of Operation Drumbeat were known as the “Second Happy Time.” Flush with success, Dönitz sent more and more U-boats into the battle.

Andrews appealed in vain to King for the firepower to fight back: destroyers, planes, whatever it took to track down and kill the seeming horde of U-boats that were having their way in American waters. At this point in the battle, however, neither King nor Andrews was ready to accept the conclusion the British had reached early on: the only way to get merchant vessels safely through U-boat–infested waters was by guarded convoy. Instead, scarce assets like destroyers and coast guard cutters were sent out on hunting expeditions in the heavily traveled sea lanes. They weren’t escorting merchantmen, which would attract U-boats, but instead were hunting subs much in the random way a novice sport fisherman hunts fish in the open sea. The results of those first weeks of hunting were hundreds of depth charges expended (including some dropped on the wreck of the Civil War ironclad gunboat USS Monitor), but no Nazi subs sunk. The U-boats held complete sway over the Eastern Sea Frontier.

The Germans kept up the tempo of the attack, sinking another 32 ships in February. By now the U-boats were not strictly adhering to the doctrine of attacking only at night and lying on the bottom during the day. On February 2, Lieutenant Captain Werner Winter made a daylight attack with his U-103 on the tanker W.L. Steed, 100 miles off Ocean City, Maryland. After hitting and stopping the tanker with a single torpedo, Winter shelled the hapless tanker for 40 minutes with his 88mm deck gun. The U-boat was close to the tanker when it exploded, causing a pulse of heat that made the men on 103 shield their faces from the blast.

Two days later, Winter sank the 3,000-ton banana boat San Gil off Virginia and then doubled back north. His hunting instinct proved sound when he found the tanker India Arrow, loaded with diesel fuel, about 20 miles southeast of Cape May, New Jersey. He stalked the ship until it was perfectly silhouetted by the lights of Atlantic City. Then he put a single eel into her, and she went up in flames. When Winter and his crew turned away, she was sinking as men burned alive on her decks. On the night of February 5, Winter continued his war on the American tanker fleet, attacking China Arrow off Cape Hatteras. Two torpedoes failed to sink the tanker, which was equipped with a state-of-the-art fire suppression system. So, Winter finished off China Arrow with shells from the 88mm deck gun.

The Germans used the month of February to expand their hunting area south of the Carolinas to Georgia and Florida. On February 19, Corvette Captain Ulrich Heyse in U-128 made an attack in broad daylight off Jacksonville, Florida, against the 8,201-ton tanker Pan Massachusetts. Carrying gasoline and fuel oil, the ship burned fiercely after being hit by two torpedoes. For a change, there was a response from shore. A coast guard cutter and two navy planes went out to investigate and assist with rescue, though U-128 escaped without being attacked. On February 22, U-501 attacked the tanker W.D.Anderson just 12 miles from the lighthouse at Jupiter, Florida. Torpedoes detonated an explosion on the ship that was heard all the way down in Miami.

Old hunting grounds continued to yield rich results for the Germans. On February 26, U-578 attacked the tanker R.P. Resor, carrying 78,729 barrels of oil. The ship burned for two days, shedding smoke that was visible to crowds for miles along the New Jersey coast. Only two of the 50 men aboard survived the blazes.

Great Britain was beginning to worry deeply about the United States’ lack of response to the German offensive in its waters. When the British admiralty suggested that the United States adopt a coastal convoy system, King, who detested the British, replied coldly. Nonetheless, he did accept the Brits’ offer of 24 antisubmarine trawlers to operate in US waters.

King also gave Andrews the US destroyers Jacob Jones (DD-130) and Dickerson (DD-157) for hunting subs. The two ships steamed out of New York and past the pyre of the R.P. Resor. The Resor’s tormentor, U-578, commanded by Corvette Captain Ernst-August Rehwinkle, was still in the area and watched the progress of the Jacob Jones with a hunter’s interest. At 5 a.m. on February 28, Rehwinkle put two eels into her. One of them exploded the magazine. As the shattered ship went down, her depth charges detonated, killing crewmen who were struggling in the water. Of 200 men, only 11 survived. U-578 escaped without being attacked.

February ended in flames and catastrophe. March was just as bad, with 48 attacks, almost all of which ended in sinkings. Tankers continued to be the number one target of the U-boats, and shortfalls in oil and oil product deliveries were beginning to seriously worry the oil industry. Oil companies were afraid they would be unable to deliver enough heating and fuel oil for the northeastern states. Complaints were beginning to reach President Franklin Roosevelt, who was perhaps the only man King listened to.

Meanwhile, the lights of the American shore still blazed, silhouetting tankers and freighters for eager U-boat captains. The targets themselves continued to steam with their navigational lights lit. Sometimes entire ships were lit brightly from stem to stern. Small wonder then that the month ended with nasty tanker sinkings courtesy of U-124 and Lieutenant Captain Johann Mohr. Mohr believed all he needed to do was post himself near a navigational buoy and wait for the targets to come to him. He wasn’t far wrong. On March 21, while patrolling near Frying Pan Buoy off North Carolina, U-124 spotted the Esso Nashville. German torpedoes met the tanker. A massive explosion lifted the 13,000-ton ship and its 78,000 barrels of fuel oil off the surface of the ocean and slammed it onto its side. Another tanker, the Atlantic Sun, hove into view, and Mohr tried a long distance torpedo shot that hit but did not sink her; she escaped to Beaufort, North Carolina. On March 23, off Point Lookout, North Carolina, Mohr hit the tanker Naeco and set it ablaze with his last torpedo. A fire broke out that incinerated the tanker’s captain, Emil Englebrecht, and his entire watch. Another explosion turned the Naeco into an inferno. When rescuers arrived the next day, the site of the sinking was a vista of burned, floating corpses.

In the early morning hours of March 26, the slaughter of tankers off the Outer Banks continued when the Dixie Arrow hove into view of Lieutenant Captain Walter Flaschenberg’s U-71, which had stationed itself off the Diamond Shoals Lighted Buoy. It was 9 a.m. when the U-71 attacked. Able Seaman Oscar Chappel was at the Dixie Arrow’s helm. After the torpedo attack ignited a raging fire, most of the crew assembled at the bow of the burning ship. Chappel turned the ship into the wind to blow the flames away from his shipmates—and back toward himself—and locked the wheel in place. He was overtaken by the flames and incinerated. The U-71 hung around to watch the spectacle when the unexpected happened: a destroyer attacked! USS Tarbell (DD-142) pinged the U-71 with its sonar and made a depth-charge run at her. The charges missed, however, and U-71 zigzagged away to the east as fast as her electric motors could drive her.

The intervention of USS Tarbell was an exception to the general poor luck antisubmarine forces had in finding U-boats. Although few of the ships hunting the subs were aggressive, it was really the doctrine that guided their hunting—that individual ships should hunt on their own—that was to blame. The doctrine was firmly embedded, though, and it manifested itself afresh in Andrews’s desperate decision to resurrect a trick from World War I. Three Q ships—merchantmen fitted with concealed armament to snare attacking U-boats—were fitted out. Only one, the Atik, made contact with the enemy. Unfortunately, that enemy was the returning Hardegen and his U-123, which promptly sank the Atik. The other Q ships never sighted any enemy vessels.

By mid-April there were slight indications that the U-boat battle might yet turn in favor of the Americans. USS Roper (DD-147), a destroyer fitted with radar, was out hunting off North Carolina just after midnight on April 14, when her radar found a solid target at a range of 2,700 yards. The skipper, Lieutenant Commander Hamilton Howe, wasn’t sure the target was a sub until it started zigzagging. All doubt was erased when a torpedo just missed the Roper’s bow. Her powerful searchlight found the sub’s conning tower about 300 yards away, as the U-boat was turning hard to starboard. One of the Roper’s .50-caliber machine guns opened up, cutting down the crew of the enemy’s 88mm deck gun. Machine gun rounds continued to sweep the enemy decks as the Roper opened fire with a three-inch gun. The first round hit the conning tower; other three-inch rounds also found the sub, which sank into the water stern first. Roper then depth-charged the wreck for good measure. With the sinking of the U-85, the United States was at last on the scoreboard.

Tactical changes were in the works for Andrews’s fleet, which by April was made up of 23 large and 42 small antisubmarine vessels, including the British trawlers. The new system grouped merchant ships into mini-convoys dubbed “bucket brigades.” During the day, the convoys would be escorted on their way, and at night, they would put in at sheltered harbors. Planes, including Civil Air Patrol craft, would fly overhead. The mere sight of an airplane was known to send U-boats diving, so even an air patrol Piper Cub might disrupt an enemy attack.

These measures slowed but did not stop the loss of merchant ships. One tactic merchants had used to avoid attack was to sail 300 miles east of the Outer Banks, but the U-boats found them and continued the slaughter.

At the end of April, King and Andrews agreed that Andrews would take direct control over tanker sailings. All tanker traffic on the coast was ordered into port to await further orders. While Andrews worked on what to do next, the seaborne hauling of oil was halted, which hampered the Allied war effort from the oil-hungry factories of New England all the way to the empty petrol tanks of old England. A solution was needed fast.

Meanwhile, the range of the submarine war was increasing. In May and June, Dönitz expanded operations into the Florida Keys and the Gulf of Mexico. The mouth of the Mississippi turned out to be a particularly lucrative killing ground for the U-boats.

By mid-May planning was coming together for a true convoy system for the Eastern Sea Frontier. As convoys were implemented, U-boat skippers began to notice that sightings of individual ships occurred much less frequently. When ships were sighted, they were found in clusters with trawlers, cutters, and destroyers scurrying about in escort. Overhead, army and navy patrol planes kept an eye out for subs. The risks of attacking grew as the waters and skies filled with sub-hunters. The rejuvenated American effort began to take a toll on the Germans. The coast guard’s Icarus sank U-352, and army pilot Lieutenant Harry Kane dropped two depth-bombs on the U-701 in a perfect attack that put the sub on the bottom for good.

In May and June 1942, as the convoy system was still being phased in (with increasing enthusiasm from King, a former foe of convoys), there were 87 attacks on Allied shipping. In July and August, with well-escorted convoys moving under air cover and with the coast finally blacked out at nighttime, there were only 26. In June one U-boat was sunk, in July three, and in August one. The battle for the Eastern Sea Frontier was ending. Dönitz brought his remaining forces home in August.

The U-boats had scored the most one-sided and damaging victory against the United States of any foreign naval power. Germany had sunk 233 ships off the East Coast and in the Gulf of Mexico and killed no fewer than 5,000 seamen and passengers. Every month of Operation Drumbeat, German subs destroyed 3.5 percent of the tanker fleet for a total of 22 percent. The operation caused major disruptions in war-material production and in the shipping of supplies to the war fronts. This was Germany’s first strategic victory of the war that directly impacted on the American

Brian John Murphy of Fairfield, Connecticut, writes frequently for America in WWII magazine. This article originally appeared in the October 2006 issue of America in WWII. Find out how to order a copy of this issue here. To get more articles like this one, subscribe to America in WWII magazine.

Photos: U-boats at a Nazi base in Europe; the tanker Dixie Arrow a U-boat torpedoed it off North Carolina’s Outer Banks on March 26, 1942; a U-boat man slogs aboard the coast guard cutter Spencer, which sank his U-175 off Ireland; Y-guns (this example is shown aboard Patrol Craft 556) lobbed giant cans full of TNT at U-boats; and an official navy poster recruiting U-boat hunters.