World War II had been in progress for six weeks when on the evening of October 12, 1939, the German submarine U-47 surfaced off the Orkney Islands at the northern tip of Scotland. While the officers standing in the conning tower observed the twinkling lights ashore to the west, only the captain, Kapitänleutnant Günther Prien, knew the purpose of their mission. Security surrounding it had been so tight that only now, with the climax approaching, would it be possible to tell his men the reason for so daring a foray into enemy waters.
Following a night of observation, U-47 submerged and withdrew eastward. As it settled on the bottom, the motors were cut and Prien ordered the crew to assemble in the forward mess. The time had come to reveal to these young men—average age of 20—that the following day, they would be entering Scapa Flow.
A Symbolic Mission
Scapa Flow had a special significance to the officers and men of Germany’s Kriegsmarine. It was at Scapa Flow that the pride of Germany during World War I, the High Seas Fleet, with which it had sought to challenge the Royal Navy for control of the seas, had been scuttled, laid to rest in a final defiant act following the defeat of its armies in northern France and Flanders. There, its ships lay as they still do, in 15 fathoms of water. The superb natural harbor provided ample protection for large numbers of British warships and a perfect position from which to intercept German vessels attempting to escape into the North Atlantic. Prien was proposing an extraordinary act.
The German Navy was very much the least favored of the three services at the outbreak of the war. The glory went to the Army and in its support, the Luftwaffe, as they sliced through Poland in a few short weeks. The mind-set of Hitler’s high command was geared to fighting battles on the continental landmass, and little imagination was applied to the problems faced by naval forces. Nor were the consequences, either tactical or strategic, considered of an enemy whose principal strength was naval.
The importance of the U-boat arm was overlooked in favor of large surface units such as the battleships Bismarck and Tirpitz. Kommodore Karl Dönitz, the head of the U-boat arm, desperately wanted a major success to impress upon Hitler the importance of developing the U-boat program. While serving as a U-boat commander in World War I, Dönitz had himself slipped his boat into a defended harbor in Sicily and gotten out again without detection. If such a feat could be repeated, it could prove a calamitous blow for the Royal Navy in both materiel and prestige, and equally glorious proof of the value of his submarines.
Dönitz had been appointed commander of the new Nazi submarine fleet in September 1935, during the years of appeasement when the British unilaterally gave the Germans the go-ahead to start building submarines once again via a naval treaty. The Germans had been prevented from doing this as part of the settlement of World War I, but they had maintained their skills through antisubmarine warfare training. A thoughtful and far-sighted commander who knew that Britain could not be defeated by a few isolated successes by powerful submarines, Dönitz was desperately keen to ensure he had the wherewithal to conduct a protracted campaign with a substantial fleet that could wear down the British through sustained and heavy attrition. He wanted the ability to sweep an area of sea and then concentrate for night attacks, and for this he needed quantities of relatively simple boats. The Type VII boats, such as U-47, were perfectly suited to his requirements.
“Get Your Boat Ready”
To have even the most remote chance of success in Scapa Flow, Dönitz needed intelligence. U-16was sent to reconnoiter the waters, tides, and currents while all available charts were collected together with aerial photographs. Close examination of these suggested that Scapa Flow was not as well defended as they had expected. The antisubmarine booms and sunken blockships had been sufficient during World War I when two German submarines were lost attempting similar operations, but gaps were now apparent and the traditional defenses no longer offered complete protection to the anchorage. The best route was through Holm Sound, which divided into a number of smaller channels, one of which, Kirk Sound, was incompletely defended by blockships. If the timing was right, at slack water on a dark night, a surfaced boat could slip through the gap. It was a dangerous undertaking, but not an impossible one.
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The commander of such a raid would need to be a first-class seaman with no lack of raw courage. Dönitz chose the 31-year-old Prien, a fervent Nazi and a relative newcomer to the service. Born in 1908 in Leipzig and brought up in great poverty, he was inspired as a boy by the Portuguese explorer Vasco de Gama. Prien first went to sea at age 16 and moved up from cabin boy to merchant captain before the Depression threw him out of work. The expansion of the Navy as Germany began its rearmament program enabled him to return to sea, and there he immediately shone as a natural U-boat commander.
Prien possessed the “sixth-sense” needed for such work, together with a common touch that made him both liked and respected by his men. To Dönitz, “Prienchen” was the ideal skipper for this special task: he had scored the U-boats’ first official victory (not counting the liner Athenia, sunk on the first day of the war—even the Nazis denied that publicly). He had sunk three ships totaling over 66,000 tons on his first war patrol and won the Iron Cross, Second Class.
Standing before Dönitz in the Weichsel, Prien glanced at the charts on the table and saw the map of Scapa Flow on top. He could barely contain himself as Dönitz outlined his “Special Operation P.” Finally, Dönitz asked, “Do you think a determined commander could get his boat inside Scapa Flow and attack the enemy’s forces lying there?” He gave Prien 48 hours to look over the accumulated charts, photos, and intelligence and deliver a carefully thought-out assessment.
After supper at home, Prien sent his wife and young child out for the evening and spread the documents on his writing table. Dönitz had been planning the venture for some time, and there was a wealth of intelligence. Aerial photos taken as early as September 6 showed the entire Home Fleet at anchor and antisubmarine booms and sunken ships blocking the bay’s seven entrances. A U-boat scouting the inlets had found scant defenses but 10-knot rip tides. Navigation, even in daylight, would be tricky at best. But in Kirk Sound, the northernmost of the Flow’s three eastern inlets, the blockships Thames, Soriano, and Minich lay just far enough apart that a U-boat might zigzag through in the slack water just after high tide.
The tide on the night of October 13 would be one of the highest that year, and there would be no moon. “I worked through the whole thing like a mathematical problem,” Prien related in his autobiography, Mein Weg Nach Scapa Flow (My Way to Scapa Flow—most recently published by Tempus as U-Boat Commander). The next day he reported ahead of deadline. Dönitz was at his desk. “He did not acknowledge my salute; it seemed as if he hadn’t noticed it. He was looking at me fixedly and asked, ‘Yes or no?’”
Prien answered, “Yes, sir.”
“Very well,” said Dönitz as he came around to shake Prien’s hand. “Get your boat ready.”
An Elite Crew, an Advanced Ship
The crew selected for this mission were all hand-picked volunteers, already proven in their ability to handle the extreme pressure of submarine warfare. Oberleutnant zur See Englebert “Bertl” Endrass, the first officer, would later become a U-boat ace in his own right in U-46 and U-567. Oberleutnant zur See Amelung von Varendorff, the second officer, would captain U-213, and the other 42 men of crew were all volunteers, products of the grueling U-boat school that required 66 simulated attacks on the surface and 66 more submerged before the firing of a single torpedo. On October 8, U-47 was ready to set sail from Kiel.
Passing through the Kiel Canal and entering the North Sea, the Germans headed for Heligoland for final trim trials. The Type VIIB U-boat was the most advanced model in the German Navy at the time, although it was not strictly a submarine in the modern sense and was capable of only short distances under water at low speed. U-boats normally traveled on the surface unless attacked by aircraft or surface vessels. Attacks would be delivered on the surface if possible, unless against well-defended convoys. These boats were armed with 15 torpedoes with four bow-firing tubes and one at the stern. U-47 was also armed with an 88mm deck gun and a 20mm antiaircraft gun.