CONFIDENTIAL (Reference to this report must specify Serial No., Place and Date.)
Serial       155-C-48       at       F.P.O., N.Y.       Date       3 April  , 1948    
(Start new series each year, c,. 1-43, 2-43.)
From       COMNAVNORGER         MONOGRAPH INDEX GUIDE NO.                                          
(Ship, fleet, unit, district, office, station, or person) Make separate report for each main title. See O. N. I. Index Guide.
(Directive, correspondence, previous related report, etc., if applicable)
Source       As noted herein.       Evaluation       B-2          
(As official, personal observation, publication, press, conversation with--
(identify when practicable, etc.)
A-1 to F-0 etc.
Ref: AB/EN 3-10; SER.4312416--11-18-42
Subject       GERMANY, Navy, Historical, Operations (U-47).      
      (Nation reported on)     (Main title as per Index guide)     (Subtitles)     (Make separate report for each title)      

BRIEF. (Here enter careful summary of report, containing substance succinctly stated; include important facts, names, places, dates, etc.)

Authentic account of U-47's (ex-
Kapitaenleutnant Guenther PRIEN) penetration
of SCAPA FLOW and attack executed on battle-
ship units of the British Home Fleet.

* * * * *

1. Ex-Admiral Wagner Fuerbringer, German Navy, is the source of the below-given account of the U-47's SCAPA FLOW undertaking in the early part of World War II. It will be recalled that ex-Kapitaenleutnant Guenther Prien, Germany Navy, (later missing from another undertaking), was in command of the U-47 when this venture was carried out against the British Home Fleet. The below description of this exploit formed the basis of Fuerbringer's lecture before the Japanese Admiral Nomura and his Staff in 1941. Prien subsequently published a book on this undertaking but for obvious reasons had to obscure certain details. In order not to deprive Prien's wife of an opportunity for realizing a little money through publication of a subsequent book, including all of the details given in the below account, Fuerbringer requested that the details he has now provided not be publicized; however, no objection would be voiced in disseminating same to official U.S. Navy circles.

2. Fuerbringer entered the Imperial German Navy in 1907, was retired in 1920, and recalled to active duty as an "Erganzungsoffizier" in 1935. During World War I he was a

Distribution By Originator             CINCNAVEASTLANTMED(1).          

Routing space below for use in O. N. I. AA 72356 |       CLASSIFICATION       |
Op-29 Anti Sub Development Detachment
Op-31 (3) CIA (4)
Op-34 (3) MID (7) Op-32-F-114 (2)
CinCLantFlt       32-Y (3)
CinCSubLant       32-F-2 (3)
CinCPacFlt       32-F-111
ComSubPac       32-FN
BuShips (4)       32-F-11 (2)
U.S. Naval Sub Schl.      
U.S. Naval War Col.       SER/FIR
USN Sch; gen.Line, Newport      
JCS (Hist. Section)      


Serial: 155-C-48 of 3 April 1948.
Subject: GERMANY. Navy. Historical. Operations (U-47).

well-known U-boat Commander and during World War II he was initially assigned to O.K.M. where he worked in U-boat questions and later (1942) he was appointed Chief of Ruestungsinspektion Ostland, with headquarters in Riga. After ex-Grossadmiral Doenitz assumed Supreme Command of O.K.M. in early 1943, Fuerbringer, along with almost all other officers who were senior to DOenitz, was retired. In view of his assignment as Chef der Ruestungsinspektion Ostland (1942/43), he has now been solicited to draw up an essay on the potential of the Baltic ports of NARVIK, REVAL, RIGA, BALTIC PORT, WINDAU and LIBAU which work will be forwarded to the Department when completed.

* * * * *


"The decision of Seekriegsleitung (Naval Operations) to penetrate SCAPA FLOW--the main anchorage of the British Home Fleet--with a U-boat and to attack English units anchored there was based on the following:

(a) Various observations and reconnaissance had indicated that the blockade thrown up around Scapa Flow was technically primitive in at least two of the six entrances and that English guarding thereof was not thoroughly effective. It was thus held that a breakthrough via one of the two entrances in question appeared to have certain prospects of success if the undertaking were prepared with the required circumspection and executed cold-bloodedly and resolutely.

(b) Intelligence and aircraft reconnaissance apparently confirmed that the security of the ships anchored in Scapa Flow was, in general, being carried out by inadequate forces and in more or less weak form. Thus it was concluded that if this bay could be forced sans detection, then the prospects for the U-boat's escape after launching its attack against the anchored units would present no undue difficulties.

(c) General confidence prevailed that on its return trip the U-boat would encounter precisely the same difficulties attending the forcing of the entrance assuming that the escape was made in the shortest possible time directly after launching the attack and without being detected.

Accordingly, the undertaking was prepared within the framework of the foregoing points. Left open at the time was the question as to which of the two entrances should be chosen to break through into the bay, namely, the passage through SKERRY SOUND, or that through KIRK SOUND. Selection of the entrance route, of course, depended on which one offered the most favorable possibilities. Both routes had the great


Serial: 155-C-48 of 3 April 1948.
Subject: GERMANY. Navy. Historical. Operations (U-47).

advantage of having their coastal areas practically entirely uninhabited, and therefore no special apprehension needed to be attached to detection of the U-boat from ashore while making its passage. SKERRY SOUND, however, appeared to have the disadvantage of being blockaded more effectively. Thus Seekriegsleitung finally decided upon using the KIRK SOUND entrance. True, this channel was blockaded (guarded) by three anchored ships, but north and south of this blockaded area towards the shore there was a small opening, unguarded, and one of these two openings was to be used by the U-boat for breaking through. It was decided to use the northern opening as this was still marked by an anchored bark and would be easy to recognize in darkness.

Kapitaenleutnant Prien was chosen to carry out this most difficult undertaking. After the very secret preparations had been completed, his boat left port and proceeded to the northern North Sea and from there felt its way cautiously to the approaches of HOLLY SOUND. All the daylight observations that had been made in the bay had led to the belief that the planned chance of success, providing that:

  1. the same conditions of blockade, as observed by day, also prevailed by night; and

  2. the night would be sufficiently light to afford recognition of details of the narrow passage.

The difficulties imposed on the U-boat's commander in forcing penetration were primarily navigational in character. He therefore indoctrinated himself so well in this field that he was able to memorize the minutest detail on his chart and as a result he did not have to refer to his chart for even a second during the break-through passage.

There were no reliable reports at hand as regards the laying of mines and nets and therefore the U-boat in question had to be protected with all appropriate technical security measures It had also to be taken into account that the U-boat might possibly encounter enemy ships at close range and therefore its guns had to be kept ready for instant action.

Due to the navigational difficulties attending the passage of KIRK SOUND, the planned time of starting the break-through was to conform to conditions of "Stauwasser" (stagnant or calm sea). However, due to the necessity for traveling submerged for a long time--which had been unforseen--Prien's boat arrived in HOLM SOUND behind schedule. Sea conditions showed that the break-through would have to be made with the current. This was an unfavorable circumstance because the break-through would now develop at a much greater speed than was advisable in view of the totally unknown waters (area) and the possibility of encountering surprises in these channels. Therefore the boat's speed would have to be reduced in order to afford opportunity to survey the channel and in so doing the very important factor of maneuverability would be adversely challenged.


Serial: 155-C-48 of 3 April 1948.
Subject: GERMANY. Navy. Historical. Operations (U-47).

When the U-47 surfaced by darkness at ROSE NESS, somewhat behind schedule, the entrance into HOLM SOUND was clearly recognized. Insofar as could be determined, the entrance was not under guard. However, visibility conditions were bad; everything on land was pitch black while the skies were radiating the bright Northern Light. The bay itself was thus peculiarly lighted, whereby dead ahead over the water's surface great visibility prevailed, while on both sides of the coast there was impenetrable darkness and uncertainty.

Proceeding further into the bay the U-47 sighted a sunken steamer on the port side. Prien concluded that he was now in KIRK SOUND and pulled up close aboard the steamer. In the interim the helmsman established that the turn had bee made to son and that the U-47 was on a false course. Almost simultaneously Prien realized that he had erred and had inadvertently entered SKERRY SOUND. At the same moment the boat was turned to starboard with hard rudder and avoided in good time the threatening danger of being forced by the strong current into the sunken steamer.

A few minutes later KIRK SOUND was clearly observed on the port side and the U-47 headed in. The three guard ships were clearly recognized; shortly thereafter the U-47 picked up the two-masted bark which lay just ahead of the guarded area. The U-47 had scarcely passed the latter at about 15 meters distance when it was caught by the current, making it impossible for the boat to use its rudder effectively, and which forced the boat to starboard close inshore. At the same time, the anchor chains of the northern guard ships were clearly seen, 45 degrees north, ahead. It was precisely now, when the boat was unable to get its rudder to respond, that the time had some when decision had to be made to try to steer through the almost hair-like thin stretch between the anchor chains and the nearby shore. Tense seconds followed until efforts to get the boat under control and to set it on the right course succeeded. Scarcely had this been done than there followed several sharp impacts which shook the entire boat--it had grounded and was being held fast on the bottom.

Prien summed up the situation in a fleeting second with his chief engineer who was on the command bridge at the time. And almost instantly the order was given by the bridge to open the air pressure valves for blowing out the diving tanks which had been previously flooded. Seconds later the boat raised itself from the bottom, resumed passage and was so maneuvered that only the end of the stern hit the anchor chain of the guard ship with a loud ring. Almost simultaneously the boat was again caught by the current and veered to port, threatening to ground on the shore. Prien ordered emergency full speed and was able to bring the boat under control again on the desired course. Now there were no further obstacles to overcome; the forcing of the Sound had succeeded. The U-47 was now in Scapa Flow and steering a western course in the center of the bay. There was not time for the crew to reflect


Serial: 155-C-48 of 3 April 1948.
Subject: GERMANY. Navy. Historical. Operations (U-47).

on the miracle. The night was still almost daylight over the water's surface. And now the most important phase of the mission imposed itself: Just what was the situation as regards the anchored south of CAVA island where strong English fores were supposedly concentrated! All glasses on the bridge were pointed ahead--everyone wanted to be the first to detect the English ships. But, to the disappointment of everyone, the anchorage south of CAVA was completely void of ships.

In the shock accompanying this discovery the U-47 had momentarily neglected to pay any attention to the numerous guardships to the south of HOXA SOUND. These ships suddenly loomed up so clearly that it appeared impossible for the U-47 to escape detection. With hard port rudder and maximum emergency speed the boat was brought on an opposite course. Anguishing minutes of uncertainty passed, but the guard ships apparently had not been aroused by the U-47's presence, and soon the boat was brought to the safety of darkness close inshore. It was now that the entire bay was thoroughly surveyed for the first time for it was not believed that absolutely no targets were in the area. Suddenly the lookouts reported that just north of CAVA island two heavy battleships were at anchor; these became plainer from minute to minute. Their enormous hulls shaped up against the background like huge dark mountains. Further inshore several destroyers were sighted.

The moment had now come to take advantage of the situation. The U-47 approached the coast as close as it was navigationally safe to do in order to remain undetected by the guard ships and destroyers in the north and proceeded in a northerly direction. Upon nearing the anchored battleships the U-47 turned hard towards them and at 3,000 meters range launched a surface bow-torpedo attack. Of the three torpedoes fired within three and one-half minutes, only one found its target--the battleship further to the north. The other two torpedoes missed. Already during the running time of the first torpedoes the U-47 turned at high speed to carry out a stern attack--this was a salvo of two torpedoes. After three minutes both torpedoes hit the closest battleship. In the meantime the boat turned around again to renew a bow-attack; even faster than previously the loading crew placed the three reserve torpedoes in the tubes. With enormous repercussion this last torpedo salvo left the tubes and again registered three hits on the nearest battleship and again these hits were confirmed by water and fire spouts extended high into the skies. All of this was observed when the U-47 started out on its return trip at full speed.

In the interim the entire bay had become alive. Destroyers lighted up the sinking battleships with their searchlights. Ashore, autos were using their headlamps and spotlights, and it appeared that they had sighted the boat with the aid of the lighted skies and were now attempting to hasten its trapping. Now the race between the U-47 and its pursuers developed.


Serial: 155-C-48 of 3 April 1948.
Subject: GERMANY. Navy. Historical. Operations (U-47).

Despite the darkness of the coasts, the steering route for KIRK SOUND via SKILD[...]UOY POINT was found quickly, but scarcely had this corner been rounded than the full fury of the counter-current from KIRK SOUND was met. At this moment when the top speed of the boat meant everything, the question arose as to whether the machinery would respond instantly or move only slowly ahead. Minutes seemed like an eternity.

As ebb-tide was running, the level of water had dropped so greatly in the interim that the passage through the northern [..."]--where the U-47 had hit bottom on its inward journey--could not now be risked. Therefore the outward passage would have to be made through the "hole" in the southern blockade which was entirely new. In order to negotiate this passage which was a very narrow strip between the guardships and the shore, steady maneuvering was required. Scarcely had the boat forced its way through this "hole" than directly ahead at very close range a mole was sighted which for an instant invited danger by ramming. Because of the unfavorable light conditions it could not be seen which side of the mole should be followed. Prien instinctively gave the boat hard rudder to starboard and in so doing did what was right. Now the boat was in a free channel and now, after an almost endless 3,000 meters of uncertain passage, the proper diving depths had been reached. And thus the U-47 had defeated the efforts of its pursuers. The boat's return to home port was negotiated without special events.

This undertaking of the U-47 was something that happens but once in a lifetime and constituted the most daring feat ever accomplished by a German submarine. The Commander and crew accomplished exactly that which was possible to do under the given circumstances. The boat's success might have been considerably greater if 3 battleships and ten cruisers had not left for sea during the late hours of the afternoon in question."


Transcribed and formatted for HTML by Patrick Clancey, HyperWar Foundation