The Sinking of British Battleship, HMS Royal Oak, at Scapa Flow, by German Submarine, U-47

This Marshall Islands stamp depicts Gunter Prien sinking Royal Oak, after he penetrated Scapa Flow
This Marshall Islands stamp depicts Gunter Prien sinking Royal Oak, after he penetrated Scapa Flow
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.

Gunter Prien

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.

Map of Scapa Flow

Appendix 1 is an extract from Gunter Prien's Log of  U-47, covering his penetration of Scapa Flow, and sinking of the British Battleship HMS Royal Oak, in September 1939.

Appendix 1

Extract from Log of U-47, 15th Sept. - 21st Oct. 1939.

Time   Position, Wind, etc.   Incidents 
1100   Heligoland Bight. Wind SE 1. Cloudy   Left port (Kiel) on special operations, Operational Order North Sea No. 16, through Kiel Canal, Heligoland Bight, and Channel 1.

Exact positions cannot be given as under special orders all secret documents were destroyed before carrying out of order


South of Dogger Bank. Wind SSE 4-5. Overcast, very dark night. Lying submerged. After dark, surfaced and proceeded on our way. Met rather a lot of fishing vessels.


North of Dogger Bank. Wind SSE 7. Overcast.  During day lay submerged; at night continued on course.


Devil's Hole. Wind ESE 7-8, Overcast   During day lay submerged off Orkneys. Surfaced in the evening and came in to the coast in order to fix exact position of ship. From 2200 to 2230 the English are kind enough to switch on all the coastal lights so that I can obtain the most exact fix. The ship's position is correct to within 1.8 nautical miles, despite the fact that since leaving Channel 1 there was no possibility of obtaining an accurate fix, so that I had to steer by dead reckonings and soundings.


E. of Orkney Islands. Wind NNE 3-4, light clouds, very clear night, Northern Lights on entire horizon.   At 0437 lying submerged in 90 meters of water. Rest period for crew. At 1600 general stand-to. After breakfast at 1700, preparations for attack on Scapa Flow. Two torpedoes are placed in rapid loading position before tubes 1 and 2.

Explosives brought out in case of necessity of scuttling. Crew's morale splendid. Surfaced at 1915. After warm supper for entire crew, set course for Holm Sound. Everything goes according to plan until 2307, when it is necessary to submerge on sighting a merchant ship just before Rose Ness. I cannot make out the ship in either of the periscopes, in spite of the very clear night and the bright lights. At 2331, surfaced again and entered Holm Sound. Following tide. On nearer approach, the sunken blockship in Skerry Sound is clearly visible, so that at first I believe myself to be already in Kirk Sound, and prepare for work. But the navigator, by means of dead reckoning, states that the preparations are premature, while I at the same time realize the mistake, for there is only one sunken ship in the straits. By altering course hard to starboard, the imminent danger is averted. A few minutes later, Kirk Sound is clearly visible.

13/10/39 contd.

It is a very eerie sight. On land everything is dark, high in the sky are the flickering Northern Lights, so that the bay, surrounded by English mountains, is directly lit up from above. The blockships lie in the sound, ghostly as the wings of a theatre. I am now repaid for having learnt the chart beforehand, for the penetration proceeds with unbelievable speed. In the meantime I had decided to pass the blockships on the Northern side. On a course of 270 I pass the two-masted schooner, which is lying on a bearing of 315 in front of the real boom, with 15 meters to spare. In the next minute the boat is turned by the current to starboard. At the same time I recognize the cable of the northern blockship at an angle of 45 degrees ahead. Port engine stopped, starboard engine slow ahead, and rudder hard to port, the boat slowly touches bottom. The stern still touches the cable, the boat  becomes free, it is pulled round to port, and brought on to course again with difficult rapid maneuvering, but; we are in Scapa Flow.  

0027  It is disgustingly light. The whole bay is lit up. To the south of Cava there is nothing. I go farther in. To port, I recognize the Hoxa Sound coastguard, to which in the next few minutes the boat must present itself as a target. In that event all would be lost; at present South of Cava there is no shipping; so before staking everything on success, all possible precautions must be taken.

0055  Therefore, turn to port is made. We proceed north by the coast. Two battleships are lying there at anchor, and further inshore, destroyers. Cruisers not visible, therefore attack on the big fellows. Distance apart, 3000 meters.

0116  (time queried in pencil, 0058 suggested) Estimated depth, 7.5 meters. Impact firing. One torpedo fixed on the northern ship, two on the southern. After a good 3 1/2 minutes, a torpedo detonates on the northern ship; of the other two nothing is to be seen.

0121  (queried to 0102) (suggested time 0123, in pencil)   About! Torpedo fired from stern; in the bow two tubes are loaded; three torpedoes from the bow. After three tense minutes comes the detonation on the nearer ship. There is a loud explosion, roar, and rumbling. Then come columns of water, followed by columns of fire, and splinters fly through the air. The harbor springs to life. Destroyers are lit up, signaling starts on every side, and on land 200 meters away from me cars roar along the roads. A battleship has been sunk, a second damaged, and the other three torpedoes have gone to blazes. All the tubes are empty. I decide to withdraw, because: (1) With my periscopes I cannot conduct night attacks while submerged. (See experience on entering.) (2) On a bright night I  cannot maneuver unobserved in a calm sea. (3) I must assume that I was observed by the driver of a car which stopped opposite us, turned around, and drove off towards Scapa at top speed. (4) Nor can I go further north, for there, well hidden from my sight, lie the destroyers which were previously dimly distinguishable.

0128 At high speed both engines we withdraw. Everything is simple until we reach Skildaenoy Point. Then we have more trouble. It is now low tide, the current is against us. Engines at slow and dead slow, I attempt to get away. I must leave by the south through the narrows, because of the depth  of the water. Things are again  difficult. Course, 058, slow - 10 knots. I make no progress. At high speed I pass the southern blockship with nothing to spare. The helmsman does magnificently. High speed ahead both, finally 3/4 speed and full ahead all out. Free of the blockships - ahead a mole! Hard over and again about, and at 0215 we are once more outside. A pity that only one was destroyed. The torpedo misses I explain due to faults of course, speed, and drift. In tube 4, a misfire. The crew behaved splendidly throughout the operation. On the morning of 13/10, the lubricating oil was found to have 7-8% water in it. All hands worked feverishly to change the oil, i.e. to get rid of the water and
to isolate the leaking point. The torpedo crews loaded their tubes with remarkable speed. The boat was in such good form that I was able to switch on to charge in the harbor and pump up air. 

0215  Set SE course for base. I still have 5 torpedoes for possible attacks on merchantmen.

0630  57° 58' N, 01° 03' W   Lay submerged. The glow from Scapa is still visible for a long time. Apparently they are still

1935   ENE 3-4, light clouds, occasional rain, visibility bad towards land, otherwise good  dropping depth charges. Off again, course 180°. This course was chosen in the hope that we might perhaps catch a ship inshore, and to avoid U-20.


0600   56° 20' N, 0° 40' W   Submerged and lay at 72 meters. From 1000 onwards, depth charges were dropped from time to time in the distance. 32 depth charges were definitely counted. So I lie low, submerged, until dusk.

1823   Wind NE 5, sea 4, swell from E, cloudy, visibility good. Surfaced. On surfacing, Norwegian steamer "METEOR" lies ahead. W/T traffic from the steamer is reported in error from the W/T office; I therefore fire a salvo far ahead of the steamer which is already stopped. The steamer is destined for Newcastle on Tyne, with 238 passengers. Steamer immediately allowed to proceed. It is reported later by the W/T office that the steamer did not make any signals.


0702   54° 57' N, 2° 58' E, Wind NNW 2-3, visibility good. General course 180°. Submerged on the Dogger Bank. 3 drifting mines sighted, 54° 58' N, 2° 56' E. No measures taken, owing to the proximity of fishing vessels. Proceeded submerged throughout the day.

1856   54° 51' N, 3° 21' E, Wind NW 2, light clouds, visibility good. Surfaced. Course 128°. Steered course of 128° into Channel 1.


0404  Channel 1 passed. From 0404 to 0447 chased fishing vessel escort ship no. 808; gave recognition signal eight times - no reply received. This fool did not react until V/S was used at a distance of 500-600 meters. With such guardships, an incident such as my operation could occur in our waters also.

1100  Entered port - Wilhelmshaven III.

1144  Tied up.

1530  Crew flown to Kiel and Berlin


1600  Crew returned. Sailed for Kiel.

2330  Met an armed fishing trawler at anchor with riding lights in the stretch between Elbe I and Elbe II. I pass him with darkened ship at a distance of 40 meters. Apparently he sees nothing, because no recognition signal is made.


0120 Tied up at Brunsbüttel Lock.

1300  Tied up at Holtenau Lock.

Operation completed.



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