Over two World Wars, Scapa Flow in the Orkneys, was the main Fleet Anchorage in the British Isles for the Royal Navy,

During WW1, the German Submarine UB-116 commanded by Oberleutnant Hans Joachim Emsmann had, in October 1918, attempted to penetrate this British Base, but had come to grief on a mine, and was lost with all hands.

Just after going to war against Britain in September 1939, the German U-Boat Commander, Admiral Donitz, was keen to upset both the Royal Navy, and her First Lord of the Admiralty, Winston Churchill, by breaching the defences of Scapa Flow and sinking a major Naval Vessel.

In September 1939, U-14 had carried out a patrol in that area and brought back valuable information about the approaches to this major Fleet Base.

In addition, the Luftwaffe, on the 26th. of September, had managed to obtain excellent photographs of this seemingly impregnable anchorage. At least the British believed it was inviolable; but not so, thought Donitz.

The defences of Britain's major naval base were still not complete 6 weeks after the commencement of hostilities with Germany.

Donitz studied the reconnaissance photographs, and decided that a 50 foot gap existed between the blockships which had been sunk in the northern end of the most eastern entrance in Kirk Sound, and he thought that a surfaced Submarine could penetrate this narrow access at the time of slack water.

But, a night attack would be mandatory.

On Sunday the 1st. of October 1939, Donitz sent for one of his best submarine Captains, Kapitanleutnant (equivalent to our Lieutenant Commander) Gunter Prien, and offered him the mission of taking his U-Boat, U-47, into Scapa Flow to sink a major British warship.

Prien had been born at Leipzig in Saxony in 1909 , and left school at 14, to become a cabin boy at sea.

He rose to be a Merchant Marine officer, but come the depression, he was out of a job. Somewhat embittered by being unemployed in his early twenties, Prien joined the Nazi Party in 1932, and in the following year joined the Navy as an Ordinary Seaman. He was quickly seen as Officer material, became a Cadet, joined the Submarine service and by 1938 had risen to command level.

When WW2 broke out, Prien was in command of U-Boat 47, and had recently been married.

It was made quite clear to Prien, that he could refuse this task without damaging his bright career, but Prien after studying the plans overnight, decided to accept this formidible challenge.

On the 8th. of October 1939, Prien took U-47 through the Kaiser-Wilhelm-Kanal and cleared her into the North Sea. Whilst enroute to Scapa Flow he took particular care to avoid any vessels that might betray his whereabouts. At 2331 (11.31 PM) on the 13th of October (obviously not a superstitious sailor) Prien commenced his run into the British Naval stronghold.

Because of the strong currents obtaining in this area, he chose the slack water period (the time in between the tide changing from ebbing to flowing or vice versa, when there is no actual water movement) and navigated his boat on the surface, between vessels sunk in the channels by the British, designed to stop such a passage by a U-Boat or any other enemy craft.

At one stage of Prien's approach, he was so close to the shore that a passing car's headlights illuminated his crawling submarine, but he continiued undetected.

Just after midnight on the 13/14th of October, he noted in his War Diary at 0027 (2.27 AM) " WIR SINDIN SCAPA FLOW!!" (WE are in Scapa Flow!!)

For the Royal Navy it was fortunate that the major units of the Home Fleet had not yet returned to Scapa Flow after chasing a strong German Naval Force, led by the Battlecruiser Gneisenau, which had sortied into the North Sea.

Inside the anchorage, Prien looked for any likely targets and sighted two large ships to his north. At 0058 (58 minutes past midnight) he fired a spread of 3 torpedoes, and after 3.5 minutes, one explosion was heard. Prien was pleasantly suprised when it did not appear to attract any attention from the British.

He swung his boat, and then fired the stern tube, but without any success.

His crew rapidly reloaded the torpedo tubes and at 0122 (1.22 AM) another 3 fish were fired. 3 minutes later, explosions were heard, and the 31,000 ton Battleship, HMS Royal Oak sank in 13 minutes, leaving only 375 survivors.

She took 24 Officers and 809 Sailors with her to a watery grave.

Amongst her survivors was the only Australian on board. Lieutenant Commander F.N. Cook RAN.

Royal Oak was the second largest ship sunk in the war by a German U-Boat.

Notwithstanding the swift incoming currents, Prien was able to pilot his U-47 away from the hunting British Destroyers, and he slipped out of Scapa Flow to head for home.

The British wrongly announced that they had sunk the offending U-Boat.

On the 14th. of October, the BBC announced :

 "This is the BBC Home Service. Here is the news bulletin. As it was reported late this morning, the Secretary of the Admiralty regrets to announce that HMS Royal Oak has been sunk, it is believed by U-Boat action. Fifteen survivors have been landed....."

Prien had achieved a magnificent coup, he took his boat back to Wilhelshaven, arriving there on the 17th of October at 1144, (11:44 AM )

The entire crew were flown to Berlin to be personally greeted by Hitler, and Prien was awarded The Knight's Cross, and Hitler entertained the crew to lunch.

Prien in his U-Boat career, sank 31 ships for a total of 194,103 tons, and was involved in 10 patrols, spending 237 days at sea on this duty.

He went missing on the 7th of March 1941, in the North Atlantic, near the Rockall Banks, it is not certain how he or U-47 died, but for many years it was believed that HMS Wolverine was responsible for sinking this U-Boat. Later intelligence suggests that Wolverine actually attacked a different German Submarine.

The loss of U-47 may have been caused by mines, by its own circling torpedoes, or by an attack by HMS Camellia and HMS Arbutus, both  Royal Navy corvettes.

By whatever means he was killed, Gunter Prien, who had lived by the Sword, had now died by the Sword. 

Germany had lost one of her U-Boat aces.