REPORT

ON

Reproduced from

British Admiralty translation

N.I.D. 24/T. 16/45

Sources consulted:

K.T.B. (Log) of Fuehrer der U-boote West (Konteradmiral DÖNITZ) covering the period 1/10/39 - 31/10/39.

Log of U-47.

Operational Orders, B.d.U., 1939/42, Part 2.

A.     General Information, Planning, etc. Source, K.T.B., F.d.U. West.

        The receipt of a wireless signal from U-47 on 15/10/39: “Operation successfully completed. “ROYAL OAK” sunk. “REPULSE” damaged.”, gives rise to Dönitz comments in his log on what he describes as “the successful completion of a long-prepared undertaking - penetration by a U-boat into Scapa Flow”.

        The possibility of such an operation is stated by Dönitz to have been under consideration since the beginning of hostilities, but exhaustive research among the archives has failed to reveal any definite record of discussions on the subject. The only definite mention that can be found which involves a higher authority than Dönitz himself is under the date 15/10/39 in his log: “I decide to proceed with the operation, and obtain approval from the Supreme Commander of the Navy in a personal interview at Naval H.Q.” This statement appears in the course of a recapitulation by Dönitz of the planning which he personally carried out prior to the operation. No date is given for the interview mentioned above, but from internal evidence it appears to have taken place at some date after September 26.

        From Dönitz' summing-up, it appears that the first step to be taken was a request that Naval H.Q. should draw up a chart of Scapa, showing location of supposed defenses. Special air reconnaissance was carried out (26 September). The results of this, described as excellent, gave a complete exact picture of Claestrom Sound, over Risa as far as Switha; parts of Hoxa Sound; Holm Sound; Scapa Bay; and Kirkwall.

        Meanwhile during the period 13th to 29th September U-14 made a special reconnaissance trip to the Orkneys, bringing back detailed reports, mainly concerning tide conditions, lights, and possible warship patrols. The entire report is to be found attached as an appendix to Operational Order No. 16 (North Sea), i.e., the Order handed to Prien

        In Dönitz' log it is stated that the Commander of U-14 held the view that a penetration into Scapa Flow through Hoxa Sound would be possible. Examination of aerial photographs, however, convinced Dönitz that this was not so. Further air reconnaissance of Hoxa Sound was carried out, which reinforced that a penetration at this point was impracticable. He states his view as follows: “I hold that a penetration through the boom in Hoxa Sound is hardly possible, and a penetration through Smitha Sound and Claestrom Sound is impracticable on account of the boom defense there.” His decision was that the attempt should be made through Holm Sound. The following is his appreciation of the situation there:

        “Holm Sound is protected exclusively by two apparently sunken ships lying obliquely in the navigable water of Kirk Sound, together with one ship lying on the north side. South of these obstructions as far as Lamb Holm there is a gap, 170 meters wide, 7 meters in depth up to the shallow water. Also north of the sunken ships there is a small gap. the

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        Kaplt. Prien was specially chosen as suitable to carry out the operation, personally briefed by Dönitz, and given carte blanche in the matter of tactical procedure. The attack was to be made if possible on the night of 13th/14th October, as on this date both low tides occurred during the hours of darkness, and it was new moon at this period. Dönitz states that U-47 was to carry torpedoes (“G.7 e”) only, it being decided to use torpedoes instead of mines, as by this means, in case of a hit, there was a greater likelihood of achieving a successful result.

        All U-boats operating off the Orkneys were withdrawn well in advance (4th October) in order to avoid arousing alarm or suspicion in the area. Last minute air reconnaissance was carried out, to confirm the presence of heavy units of the British Fleet in the area. U-47's general instructions were embodied in Operational Order No. 16 (North Sea), dated 5th October, and she left port (Kiel) on October 8th.

B.    Detailed Information (actual carrying out of the operation, etc.)

        On his return to base, Prien made the following observation, as recorded in Dönitz log: “Penetration and return through Holm Sound was possible, under great difficulties. Very little room by the block-ships; very strong tideway; on retirement, opposing current of 10 knots. No guard or watch on Holm Sound.”

        His course in and out on the surface past the block-ships in Kirk Sound is clearly shown on the track-chart attached to his log, a reproduction of which is attached herewith (Appendix 2).

        Two definite torpedo-hits are stated to have been observed by Prien: (1) forward on “REPULSE”, (2) “ROYAL OAK” seen to blow up. After observing (2), U-47 immediately left Holm Sound, observing after her departure considerable depth-charge activity in progress.

        A detailed account of the whole operation is to be found in Prien's own log, a translation of the relevant passages being attached herewith (Appendix 1).

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NID 24/T16/45

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

Time		Position, Wind, etc.		Incidents
8/10/39
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
9/10/39
		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.
10/10/39
		North of Dogger Bank. Wind SSE 7. Overcast.		During day lay submerged; at night continued on course.
11/10/39
		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.
13/10/39
		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.

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Time		Position, Wind, etc.		Incidents
8/10/39
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
9/10/39
		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.
10/10/39
		North of Dogger Bank. Wind SSE 7. Overcast.		During day lay submerged; at night continued on course.
11/10/39
		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.
13/10/39
		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.

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Time		Position, Wind, etc.		Incidents
8/10/39
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
9/10/39
		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.
10/10/39
		North of Dogger Bank. Wind SSE 7. Overcast.		During day lay submerged; at night continued on course.
11/10/39
		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.
13/10/39
		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.

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				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

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				maneuvering, but; we are in Scapa Flow.
14/10/39
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

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				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

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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.
15/10/39
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.
16/10/39
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.
17/10/39
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

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20/10/39
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.
21/10/39
0120				Tied up at Brunsbüttel Lock.
1300				Tied up at Holtenau Lock.
				Operation completed.

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