The Vulnerable Kriegsmarine Targets Scapa Flow
When World War II began, the Kriegsmarine was in a tight spot. Badly outnumbered by the Royal Navy's Home Fleet, the outbreak of war in 1939 meant that "Plan Z" – an attempt to build a navy capable of directly opposing the Royal Navy – would not be completed in time to be of use to Germany in its battle to defeat Britain. The result was that Germany had only the two Scharnhorst class battlecruisers and the three Deutschland class pocket battleships to oppose the most powerful navy in the world. Even when the battleships Bismarck and Admiral von Tirpitz came online over the next two years, Germany would still not be capable of beating the Royal Navy.
Because of its complete inferiority in terms of firepower and hulls, the German navy faced a stark choice: remain primarily a coastal defense force until attrited to irrelevance, or conduct bold strikes in the desperate hope of throwing the Royal Navy off balance. The latter being judged more suitable, plans were drawn up to attack the Royal Navy in such a way that its relentless patrols of the North Sea would be disrupted, allowing surface raiders and U-Boats greater access to the Atlantic shipping lanes. A raid on the Home Fleet's primary base at Scapa Flow in Scotland was judged to be the best means of achieving this.
U 47: Gunther Prien’s Type VII U-Boat
Raids on Scapa Flow had been attempted in the past. During the First World War two submarine raids were launched but inflicted no damage due to British patrols and the underwater obstacles guarding the entrances to the anchorage. Aware of the extreme difficulties that would have to be overcome, Karl Donitz, the head of the German U-Boat arm, chose Gunther Prien and the crew of the U 47 to launch the raid.
U 47 was a Type VII U-Boat, which was to be the most heavily produced class of German submarines with over seven hundred members – of which the majority were sunk in the perilous Battle of the Atlantic. This vessel carried a crew of around 50 and displaced under a thousand tons even when submerged. Roughly 220 feet long and 20 feet wide, the Type VII U-Boats could dive to nearly 1000 feet and make nearly 18 knots on the surface and 8 knots submerged. They were armed with five torpedo tubes (4 in the bow and one in the stern) and carried fourteen torpedoes in all.
The U 47 and its siblings were meant to provide the primary commerce raiding arm of the Kreigsmarine. With a long range and good maneuverability, these U-Boats were to form the backbone of the German submarine force right up until the end of the war, and very nearly won the Battle of the Atlantic.
HMS Royal Oak: The Ill Fated Battleship Sunk in Scapa Flow
World War Two was revolutionary in many ways, but one of the most important involved the complete movement from infantry based warfare backed by spotter aircraft, artillery, and naval engagements between battleships to the modern style of warfare that revolves around tanks, attack aircraft, aircraft carriers, and submarines. The raid on Scapa Flow was one of the earliest indicators of this radical shift.
The Royal Navy's Home Fleet was tasked with bottling up Germany's navy in port, blockading German merchant shipping, and destroying any German vessels daring enough to put to sea. To accomplish this it was equipped with two aircraft carriers, two battlecruisers, and a full six battleships. One of these was the HMS Royal Oak, a Revenge Class battleship that was also a veteran of the Battle of Jutland, fought in 1916.
Though old, the Royal Oak still represented the potency of battleships. She weighed in at over thirty thousand tons, was over 600 feet long, and was armed with eight fifteen inch and twelve six inch naval guns. She was better armed than the largest German capital ships at the time, and was deficient as a naval asset mostly in her 21 knot maximum speed which kept her and her crew of over 1000 relegated to second-line duties.
HMS Royal Oak’s Fate Approaches: Gunther Prien takes U 47 into Scapa Flow
Scapa Flow was considered by the Royal Navy to be near-impervious to submarine attack for two reasons. First, there were sunken ships in the channels leading to the anchorage that prevented any underwater entry. Some were placed there specifically to make it a difficult harbor to penetrate, and others were remnants of the German High Seas Fleet of World War I, which was scuttled in Scapa Flow after the end of that conflict (which made Scapa Flow a symbolic as well as practical target). Second, the channels were subject to wild currents that made them perilous to navigate without an experienced pilot aboard who knew the ins and outs of the harbor.
So it was that there was a low alert level inside the anchorage on the night of October 13th when Gunther Prien and crew brought U 47 into the base of the Home Fleet. It was not an easy task. The submarine ran aground on a sandbar once, and the unpredictable currents very nearly carried her out of the channel and into a dead-end sound. Threading through the blockships while on the surface, U 47 was vulnerable to being spotted from the shore or by anything afloat near to the submarine. It is largely because of the sheer daring on the part of the crew of the submarine that the attack on Scapa Flow has taken on a near legendary status in the pantheon of naval history.
Two Failed Torpedo Attacks, Then a Terrible Explosion
Once through the channels U 47 was free and clear. Searching for a target, the submarine's crew found two: HMS Royal Oak and an old seaplane tender, the Pegasus (mis-identified as a battlecruiser in the darkness of the harbor).
Under the northern lights, the U-Boat approached the Revenge Class battleship, fully aware of her size and strength. It was now the morning of the 14th of October, and after taking careful aim, U 47 unleashed a spread of three lethal torpedoes at the battleship and supposed battlecruiser from three of the forward tubes (the fourth tube malfunctioned). The crew waited, watching, counting down the seconds it would take for the torpedoes to reach their targets…
And there was an explosion – but only one, and it was muffled. U 47 turned towards the exit to the harbor, fully expecting the British vessels to come alive and attack – and as the stern torpedo tube was unmasked by the vessel's turn, Gunther Prien ordered its torpedo fired at the targets while the forward tubes were reloaded, hoping that he might get another shot before the defenses began attacking.
This torpedo missed as well. But to the shock of U 47's crew, there was no response from the British. Unbeknownst to them, one of their torpedoes did hit HMS Royal Oak's bow, and tore a hole in it. But the crew of the massive ship simply assumed normally combustible items stored in this part of the ship had detonated, and those not engaged in managing the damage incurred went back to sleep.
U 47 turned in the night, and fired three more torpedoes. All struck the Royal Oak, and she exploded with a thunderous roar.
The Sinking of the HMS Royal Oak: Consequences
More than 800 sailors died in the sinking of the Royal Oak, including over one hundred Boy Seamen under the age of 18 – it had up until that time been a standard
Royal Navy practice to bring apprentice sailors on board warships in port. This practice was ended soon after the HMS Royal Oak went down. The site of her wreck, still leaking oil, has been designated a war grave by the British government.
U 47 and Gunther Prien returned home to Germany as heroes, and the attack served its role, in part. The Royal Navy was forced to expend additional effort on developing its anti-submarine forces which materially affected the blockade. Soon after German vessels were slipping through into the Atlantic, and wreaked their share of havoc on British commerce.
This, one of the first meetings of battleship and submarine in combat, was a signal moment in naval history and a transition point to the modern incarnation of naval warfare, where the battleship has been retired as a vessel of war.