Every year on 14 October, a Royal Navy diver swims to the bottom of Scapa Flow in the Orkney Islands. He carries with him a Royal Navy ensign. His destination is the remains of a once mighty battleship, the pride of the Royal Navy, HMS Royal Oak. The diver takes his time in flying the ensign from the ships flagstaff. Even in the murky cold waters the current makes, it seems as if the flag is flying on the battleship once more. It was her destruction in the windy wilderness of these remote islands that truly marked the passing of the baton of capital ship from battleships to submarines – the very weapon system that sank her with the loss of 835 lives.
HMS Royal Oak was a Royal Sovereign class battleship designed and built just in time to see service in the closing stages of the First World War and had seen action during the Battle of Jutland. Armed with eight 15 inch guns, she was the epitome of battleship technology. Ranged against this behemoth was a small, sleek, agile and stealthy submarine, the U-47, commanded by the brilliant young German Lieutenant Gunther Prien.
At the time of the attack, the Second World War was just over a month old – too soon for the British public to have fallen under the spell of ‘The Phoney War’. News from Europe already told of staggering German successes in the East and the prospects of more to come. The Royal Navy, at a heightened state of alert, had moved the majority of its fleet to the large natural anchorage of Scapa Flow. This deep water anchorage was ideally located to allow the battleships and battlecruisers of the Royal Navy easy access into both the North Atlantic and, crucially, the North Sea to intercept and destroy German warships emerging from the Baltic region.
Whilst extremely useful to the Royal Navy, Scapa Flow did have its downsides. The area is full of navigational hazards both natural and man made. It was also a rather daunting billet for sailors used to runs ashore in Plymouth, Portsmouth or Chatham. The only entertainment was a small hall or a distant public house.
Scapa Flow had provided a home for the Royal Navy during the First World War and many of the defences found there in late 1939, dated from the earlier conflict. Many were in a state of disrepair which had a direct result on the tragedy that befell HMS Royal Oak.
To the Germans, Scapa Flow was a place of shame and humiliation for it was here that after the end of World War One the entire surviving German High Seas Fleet was interned. It was here that on 21 June 1919 the fleet of battleships and battlecruisers scuttled themselves on to the bottom of the anchorage.
In October 1939 the defences at Scapa Flow were, slowly, being made suitable. Extra manpower was being diverted into erecting boom defences around navigable channels not used by the Royal Navy vessels and the local fishing fleet. Minefields and heavy anti aircraft and anti ship guns were being sited at key strategic locations. Lieutenant Gunther Prien was, despite his youth, an experienced submarine commander. The crew of U-47 respected and admired him; his charisma urging them on to achieve their orders. His orders this time were to strike a blow for the ‘Fatherland’. Even Prien could not believe the audacity of what his superiors proposed.
Prien was to take his U-boat across the North Sea, penetrate the defences, battle the severe tide races and treacherous undercurrents around Scapa Flow, find and sink as many ships as possible and then escape back to Germany. At the time, Scapa Flow was one of the most heavily defended locations on Earth.
As U-47 approached Scapa Flow, it was just minutes from midnight on the night of 13 October 1939. The submarine crept agonisingly slowly forward constantly on the lookout for enemy vessels and defences. Onboard the tension was immense as the enormity of his task meant Prien stayed close to his submarines’ periscope. All around him his crew manned their positions in silence, painfully aware that any error could result in their destruction.
The only light that night came from the Northern Lights, but even this spectral illumination was sufficient to allow Prien to see his course. Ahead of him, as he set a course for Kirk Sound, were a number of sunken block ships, each connected with heavy sea hawsers and chains to prevent exactly what U-47 was attempting – entry into the inner anchorage. Prien’s plan was to surface and sail over the barriers – when he did his U-boat was snared and grounded. The ships’ company worked frantically to release their boat and after the screw propeller had churned the water U-47 was once again free to manoeuvre and proceeded into Scapa Flow.
Prien had expected to find the majority of the Royal Navy’s battleships and battlecruisers at anchor, but as fate would have it, most of the major units had been ordered to sea. The one major exception was HMS Royal Oak; she remained in harbour to provide anti aircraft defences for the anchorage.
Onboard HMS Royal Oak, most of her crew were asleep in their hammocks believing Scapa Flow to be impenetrable by submarines. At 0058, U-47 started to close the distance to the battleship. Prien noted, in his after battle report, that the battleship stood out like a fortress, framed by the Northern Lights and made a perfect target.