F.d.U./B.d.U.'S War Log

16 - 28 February 1941

PG30283

     
 
 
 
Date
Position, Wind, Weather
 
and
Sea State, Illumination,
Events
Time
Air Pressure, Moonlight etc.
 
 
 
 
16.2.
 
In operational sectors in the operational area:
 
U 73 Grid AE 73 t0 82
U 107 Grid 76 and 84
U 48 85 to 94
U 96 87 and 88
U 52 AM 11 and 12 (return passage on 16.2)
U 103 AL 31 and 32
U 123 as weather boat between 220 and 250 W, south of 580 N.
   
Proceeding to operational area:  U 69 south of the Faroes;  U 147 off Bergen, where it will put in for exercises inside the Fjord;  U 95, putting out of Lorient on the evening of the 16th;  U 108 putting out of Heligoland on the evening of the 16th.
 
On return passage to Lorient:  U 37, U 94, U 101 which reported the sinking of two ships of altogether 11,000 tons, and U 52 which reported being on return passage on the evening of the 16th.
 
6 Italian boats are in the area south of 580 west of 150.
 
 
The consideration that, for the time being, the thing to do is to obtain the clearest possible picture of traffic in the northern area, and that above all this will have to be obtained by a narrow, as far as possible unbroken line of boats, leads to a new disposition.  The disadvantages resulting from the lack of depth in the disposition of the boats in the event a convoy being intercepted, will have to taken into account.  The boats are assigned operational areas with a depth of 40 sea miles in the following grids:
 
U 73 7395 AE ; U 107 7643 AE
U 48 7932 AE; U 96 7949 AE
U 69 3135 AL; U 103 3174 AL
 
 
U 73 reported that there was no traffic in its area hard south of Iceland, no activity owing to weather conditions.  The sending of such messages, also by means of short signals, is forbidden owing to the danger of D/Fing.  The 10,000 ton tanker Edwy F. Brown (Grid AL 2435) reported having been torpedoed from U 103's area.
   
   
A reconnaissance report from Fliegerführer North of a battleship in Grid AM 3260 unfortunately arrived very late via both Group North and Group West as U 69 must have been approximately in the same area.  Group North is requested to insure quicker communication.
    
  
            
 
 
- 16 -
 
     

 

     
 
 
 
Date
Position, Wind, Weather
 
and
Sea State, Illumination,
Events
Time
Air Pressure, Moonlight etc.
 
 
 
 
17.2.
  After about AL 64, aerial reconnaissance yielded no results.  The urgently needed reconnaissance to the north, approaching from Stavanger/Aalborg, is still not possible owing to the weather conditions at these airfields.  Air reconnaissance is still further restricted by the fact that only one aircraft is available every day for about 14 days owing to much needed training of crews for the FW 200.I am willing to put up with these restrictions in order to attain higher figures later.
 
  U 46 put out of Heligoland for its operational area.
   
  A daylight air attack has taken place, in Brunsbüttel at midday, on Route Green in the Heligoland Bight several days ago.  This proves the necessity of proceeding during daylight in this area in a shallow sea only with anti-aircraft escort, in deep water submerged.
   
18.2.
  Torpedoed, according to Radio Intercept reports, during the night.  English steamers "Siamese Prince" and "Shaftsbury" in AM 1435 (presumably by U 69) and the American steamer "Black Osprey" in AE 7967 (presumably by U 96 or 48).  In the last few days therefore, 5 ships have been torpedoed between 590 30' and 610 30' North.  It is possible that traffic will be diverted to the north or south.  Our own boats are still in the north.  In the south the Italians have received instructions to move about 80 seamiles to the north to close the gap between the German and Italian boats.
 
 
The English D/F Service presumably intercepted U 123's weather report sent from AL 42 and U 94's approach message.  In spite of the distance, the first bearing is correct to within about 50 seamiles, the second fairly inaccurate (about 150 seamiles out).  All the same, this is yet another indication that the English D/F Service is in a position to D/F short signals also, to an increasing degree.  The boat received orders to vary the wave length used.  Apart from this the Naval War Staff has, following a telephone request from me, decreed that only one message is to be sent daily, except on special occasions, such as in the event of remarkable changes in weather conditions.
   
  U 97 has put out of Heligoland.
   
 
  U 37 has put into Lorient.  Operations on the convoy reported by Radio Intercept Service, and the maintenance of contact while repeatedly attacking from the forenoon of 8.2 to the afternoon of 10.2., are a particularly fine achievement on the part of the Commander.He was thereby the indirect cause of "Hipper's" success on 11.2.  Although "Hipper" it appears, only sank one steamer in this convoy, this operation lead to the interception of another convoy.
 
   
 
  In the evening the British steamer "Seaforth" of 4,199 tons was torpedoed, perhaps by a boat on the return passage (without reporting the fact).
       
                
            
    
 
 
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Date
Position, Wind, Weather
 
and
Sea State, Illumination,
Events
Time
Air Pressure, Moonlight etc.
 
 
 
 
19.2.
  Air reconnaissance at last over the northern area to Stavanger (one aircraft) sighted an apparently unescorted west-bound convoy consisting of 45 ships in AM 3443 in the afternoon.  Operations must be attempted by the boats - fairly well placed in the north.  The convoy appears as likely to deviate to the north as to the south.  I have therefore decided in favor of a patrol line lying in the center, ahead of the reported "W" course of the convoy.  The convoy's speed must be presumed to be 7 to 8 knots.  The boats can reach a patrol line lying to the west of the midday position of the convoy sailing at a speed of 7 knots.  If the convoy is sailing at a speed of 8 knots the boats should encounter it on the last stretch of their outward passage.  The boats are therefore ordered to take up position in patrol lines with a depth of 6 seamiles from Grid 2111 to 2377 at 1200.  U 73, 107, 48, 96, and 69 are concerned, U 103 reports having started upon the return passage.  This means a distance of 25 seamiles between boats, adequate, in view of the size of the convoy and the anticipated good visibility.  Two Italian boats will extend the patrol line to the south.
 
  Three aircraft are to carry out reconnaissance at hourly intervals from dawn on the probable convoy forces.
   
  U 108 has received instructions to proceed via the northern tip of the Faroes along the south coast of Iceland between 160 30' W and Reykjavik in order to ascertain whether there is any traffic there at all.
   
  U 46 has been ordered to operate between the Shetlands - Faroes - Cape Wrath, both boats (U 108 and 46), as it seems increasingly likely that at least a part of the British traffic has been diverted from the Northern Channel.
 
 
U 97 has put out of Heligoland, U 94 and U 101 have put out of Lorient
   
  U 94 (Lt. Kuppisch) operating west of the Northern Channel and to the North of Rockall Bank only since the 9.1., has sighted and sunk:
  In grid 8955 AE a steamer of 2,500 tons presumably bound for Iceland from England.
 
  In grid 4130 AM a steamer of 7,500 tons, in the convoy reported by U 93 on 29.1.
 
  In grid 2970 AM a steamer of 9,000 tons.
 
  The attacks were carried out with great determination.  The boat was attacked with depth charges for five hours on 29.1.
 
   
 
  U 101 (Lt. Mengersen) at sea since 24.1, was beaten off and forced to submerge by convoy escort forces on 29.1 and likewise by a smaller convoy on 30.1. which the boat unfortunately failed to report.
     
            
            
    
 
 
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Date
Position, Wind, Weather
 
and
Sea State, Illumination,
Events
Time
Air Pressure, Moonlight etc.
 
 
 
 
  Later it sank 2 steamers of 6,000 and 5,000 tons.  In addition, the boat had one or two unexplained electrical torpedo misses, which, together with those reported by U 37, give rise to great anxiety.  The matter is being looked into thoroughly.
 
20.2.
  Report of convoy in AM 2393, course 3000, at 1050, was sent by air reconnaissance at about 1130; the aircraft gave the position as correct and sent bearing signals.  Two further aircraft in 2 waves are approaching as continuous contact relief.  The situation appears therefore to be "a cinch"; the boats have received orders to attempt to establish contact.  At about 1400 the second aircraft's convoy report was received.  It was reported to be in AM 2733 and to consist of 31 steamers, 1 destroyer and 4 patrol boats, as opposed to the 40 unescorted steamers of the first convoy.  This position was also reported as "correct for U-boats".  Immediately afterwards one of the two Italian boats, which should be in the patrol lines, reported being in a totally different position far to the west; whether the other boat is in position is doubtful.
   
  The situation is at present as follows:  The convoys general course, according to aircraft reports of yesterday and early today, is 2600 and indicates roughly the southern flank of the German boats.  At the moment, these are operating to the north on a course of 3000 reported by an aircraft.  If this course was only temporary, and the enemy's general course somewhat west or slightly more to the south, there is danger of the convoy passing to the south of the boats, especially as the Italian boats cannot be counted on being to the south of the German boats.  It is better therefore, not to allow the boats to operate freely on aircraft reports, as previously ordered, but rather to attempt to intercept the convoy by means of a narrow patrol channel, as formerly, without considering the Italians.
   
  U 73, 107, 48, 96 and 69 received orders to form a patrol channel from AM 2148 to 2518.  For this purpose, they were to steer a course of about 1800 across the convoy's line of approach; the convoy should have reached this position by nightfall.
 
 
It cannot be presumed that both aircraft reports refer to the same convoy.  A radio intercept report was received in the afternoon, according to which an English Naval unit reported their convoy being attacked by aircraft in AM 2514 at 1230.  That is, 20 seamiles south of the patrol channel first allocated, where in fact, the Italians should be.  It has long been suspected however, that position reports of this kind are misleading.  For the time being therefore, I left the boats in the patrol lines last ordered, relying on the last aircraft report.  If this was correct as regard position, then contact should have been established before 1900.  This had not occurred at 2000.  The last chance was to take the radio intercept report as correct, and base further operations on it. 
   
  This i what happened, in as far as that boats received orders to take up position in a new patrol channel from AL 3821 to 0362, at high speed.
          
                        
            
    
 
 
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Date
Position, Wind, Weather
 
and
Sea State, Illumination,
Events
Time
Air Pressure, Moonlight etc.
 
 
 
 
    According to the English report the convoy can reach this position towards 1500, the boats should also be able to be there by that time, at the latest.  Only one aircraft, on the return flight from Stavanger, is available as reconnaissance, and this will operate in the area in question.  Three Italian boats are to extend the patrol channel to the north (2) and the south (1).
   
    U 47 put out of Lorient with orders to proceed to the area off the Northern Channel.
   
21.2.
  Towards 1130, a message was received from the aircraft returning from Stavanger, reporting the convoy's position in AL 3861 at 1030.  Westerly course.
   
  This message would tie up with both the Radio Intercept report from AM 2514, and the aircraft report from AM 2733.
 
 
This will have to be taken as correct as it is the only information.  On the other hand, as the boats have been making for their new position since yesterday evening in a wind of approximately strength 4 to 7, their position is not clear.  In particular, it is impossible to decide whether the boats are to the west or the east of the convoy.  It is most probable that they are to the east of the convoy, otherwise the convoy and U-boat courses must have crossed one another.  A fixed deployment of the boats is no longer possible with this uncertainty.  They are therefore, only ordered to operate on the convoy's reported position, and to attempt to establish contact.
   
    A Radio Intercept report was received towards 1300, according to which the convoy reported yesterday in AM 2514 in a Radio Intercept report, was today in AL 3455 at 1030, and was bombed by aircraft.  The longitude agrees with the aircraft report entirely, the latitude differs by 110 seamiles.  It would have been scarcely possible for the aircraft to have been in this position.  Once more then, there is a considerable difference between the Radio Intercept and the aircraft report.  This increases the suspicion that either the information given by the Radio Intercept Service is wrong, or that the English disguise their radio signals by means of a kind of recognition signal setting disc.  The aircraft report was therefore in all probability the more reliable, and further operations were based on it.  The search yielded no results, however, and was broken off at dusk.  The operations carried out since the first aircraft report at midday on the 19th, were, therefore, unsuccessful.  The reason for this is as yet obscure, it may lie in the following points:
   
1) In deployment, as the boats were sent from their patrol lines to operate on the convoy immediately on receipt of the first aircraft report, at midday on the 20th.  It would have been better perhaps, not to have dispersed the patrol lines at once, instead, for the time being to have tried to contact the convoy by means of a wide rake, and then, only when a U-boat was in contact with the enemy, to have allowed the boats to converge on it.
                                            
            
    
 
 
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Date
Position, Wind, Weather
 
and
Sea State, Illumination,
Events
Time
Air Pressure, Moonlight etc.
 
 
 
 
   
2) In that the U-boats did not reach the ordered positions owing to weather conditions, bad visibility, incorrect fixes, or that they were unlucky in their operations.  This point can be settled on the return of the boats.
3) In the weather, its influence on the positions and opportunities of the U-boats.
4) In the inaccuracy of the aircraft reports.  I intend to clear up all questions connected with this, personally, with KG 40 on the 24th, and to obtain an accurate picture of the navigational possibilities and achievements of the aircraft.
5) In the Radio Intercept reports.  3 Naval War Staff and 1 Naval War Staff suggest a clarification of the question of grading radio intercept messages.
   
22.2.
  From messages requested during the night:
 
a) U 73, 107, 96 and 69 remain in the operational area.  U 107 and 96 may soon be expected to begin the return passage.
b) U 48 is on the return passage, this boat has sunk a steamer of 4,351 tons.  U 52 reports on the return passage, having sunk 2 steamers of 7,000 tons.  Also in operational area:  U 108 off Iceland;  U 123 with freedom of movement;  U 95 as weather boat;  U 46 in the operational area between Shetlands - Faroes - Herbrides.  Outward bound:  U 552, U 97, U 47 (to the Northern Channel); U 147 (to the area Shetlands - Faroes - Herbrides - southern section);  U 73, 69, 96, 107, 552 and 97 receive operational area west of the Faroes - Herbrides area between 610 30' and 580 30' and between 70 and 120.  The impression that there is traffic here has been strengthened by events of the last few days.  Here too, a certain amount of co-operation with U 46 and later U 147 is possible.
   
  2 Italian boats are proceeding to AE 76 and 79 and AL 37 and 39.  
   
 
An aircraft returning from Stavanger reported a convoy in AN 1435.  U 552 and 46 are to operate for the time being.  This message was later corrected, the position being given as AM 2321, convoy of 40 ships, 5 destroyers, course 2600.  This corrected message was not received until 1200.
 
  U 73, 96, 69 must be in a fairly favorable position, U 107 less so.  As the boats, however, have been proceeding at "cruising speed" which can vary considerably, since the evening of 21.2, their position was too uncertain to insure the formation of a patrol line ahead of the convoy before nightfall.  In order to at least take up some kind of formation, U 73, 96 and 69 received orders to search in 20 seamile wide lines, between 600, 30' N and 590 30' N.  U 107 and U 123 which were further off were not restricted.  U 552 was to pursue if the outlook was favorable, U 46 was to remain in the operational area.  Shortly afterwards, U 107 reported being on return passage.
          
                                       
            
    
 
 
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Date
Position, Wind, Weather
 
and
Sea State, Illumination,
Events
Time
Air Pressure, Moonlight etc.
 
 
 
 
A Radio Intercept report of an aircraft attack on the convoy gave its position as AM 5371, course 2740, speed 7 knots.  The speed only was used as a basis for operations, the position is so inaccurate and an air attack cannot possibly have taken place at the point given, this proves conclusively that the information given by Radio Intercept control station no longer applies.
     
  U 73 established contact in AM 1369 at 1616, the aircraft report therefore must have been very good.  Contact must be maintained at all costs.  The night promises the best opportunities for attack.
     
  U 73 received instructions to send bearing signals and only to attack when ordered to do so.  U 96, 69 and 123 were free to attack (by day though, only under particularly favorable conditions) and were to report contact immediately in a short message.  U 73 would then be free to attack.  U 95 was also ordered to operate on the convoy and therefore relieved of weather reporting duties.
   
  No further messages were received from U 73.  It is unlikely in these circumstances, that another boat established contact during the night.
   
 
Early tomorrow morning therefore, an attempt must be made to again intercept the convoy by means of a patrol channel.  U 73, 96, 69 and 123 should then, if they have not gained contact before 2200, take up position in offensive lines from AL 2658 to AL 2869 at 1000 and approach the convoy on a course of 650, speed 7 knots.  An Italian boat is to extend the line on either flank.  These offensive lines must lie ahead of the convoy, even if the enemy's speed is 10 knots.  The contact boat is merely to maintain contact, and not to attack, so as not to be beaten off during the day.  U 99 has put out of Lorient for the north, U 105 for the south.
 
23.2.
  U 96 picked up the convoy at 1000 in AL 3552 and maintained continuous contact.  U 73 came up at 1200 and U 69 at 1530 and they reported in a short message.  The convoy deviated to the north.  U 95 and U 123 should also have been in a favorable position.  An aircraft belonging to KG 40, detailed to reconnoiter, did not appear, the convoy was at the limit of its range.
   
  U 124 put out of Lorient for the south.
     
 
24.2.
  U 96's convoy dispersed during the night after the U-boat attacks.  The following reported:
      U 96 - 7 ships 55,600 tons (3 to 26,500 from 1 convoy, including 1 auxiliary cruiser.)
      U 107 - 4 ships 21,000 tons
      U 95                (3 - 18,000
                        
            
    
 
 
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Date
Position, Wind, Weather
 
and
Sea State, Illumination,
Events
Time
Air Pressure, Moonlight etc.
 
 
 
 
    U 73 - 1 ship 6,500 tons (1 - 6,500?
  U 69 - 3 ships 25,900 tons (3 - 25,900
    U 103 - 4 ships 33,204 tons
                 22 ships 160,200 tons (10 - 76,900 from convoy
   
  U 69, 96, 107 and 123 had to start the return passage owing to torpedo and fuel shortage.  U 95 and U 108, possibly also U 97, should be able to attack during the day.  The short messages requested from the other boats giving their position, were not received.  U 552 was therefore free to attack, but lost contact at 2305 and this was not regained, although U 95 and U 97 were in the vicinity.  There was no message from U 108.  It was not until later that U 97 reported having sunk one steamer and one tanker (together 16,000 tons) damaged a further tanker, and started on the return passage.  This was fundamentally wrong (except in special circumstances).  The boat should have taken over contact duties on its own initiative, thereby enabling U 552 to attack.
   
 
U 74 put out of Heligoland for Bergen, where the boat is to exercise for about 4 days before putting out on operations.
 
25.2.
  U 103 and U 52 put into Lorient.  For the first part of their operations they saw little and had few opportunities of attacking.  U 103's total result:  4 ships of altogether 33,204 tons, U 52 - 2 ships of altogether 7,000 tons.
     
    U 552 regained contact with a section of the convoy in AE 7915, U 95 requested and received bearing signals, it must therefore have been in the vicinity.  Contact was lost, however, towards evening.  It appears pointless to continue this operation, especially as the convoy is dispersing and the weather was bad.  The boats are assigned to the following operational areas if they are not in contact with the convoy:
      U 108 between 140 00' and 170 00' West.
                        "         610 00' and 600 20' North.
      U 552 south of this to 590 40' North.
      U 95 south of this to 590 00' North
      U 70 is destined for the area north of this position.
      This area covers the traffic routes mainly observed recently.
       
      U 552 lost contact with the convoy during the night, as it dispersed.  Offensive action was restricted.  Operations on this convoy are therefore discontinued.
            
            
    
 
 
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Date
Position, Wind, Weather
 
and
Sea State, Illumination,
Events
Time
Air Pressure, Moonlight etc.
 
 
 
 
    U 47 picked up an outward bound convoy in AM 4430 at 1411.  The boat was temporarily beaten off by aircraft but was again on the scene at 1900.  U 97 and U 73 were detailed for action and ordered as a precaution to take up position in a patrol channel with U 47 at 1000 on the 26th, in case contact was lost.  Two Italian boats extended the patrol lines on the flanks, one aircraft was operating as reconnaissance. U 47 established contact, the patrol line therefore, became superfluous.  U 73 and U 99 were expected to come up, also U 97, which admittedly had no torpedoes ready for firing, and could only act as contact.
   
26.2.
  U 46 (between the Faroes and the Orkneys) received orders to return for a new screw.
   
  U 47 maintained continuous contact, but reports stopped coming in at 1700.  As the boat reported later, it had been beaten off and attacked with depth charges.  22,000 tons of shipping were sunk.  At 1931 however, U 97 took over as contact - it must also be taken into account that this boat was detailed to operate on the convoy without torpedoes.
   
  Towards 2400 the convoy dispersed, U 97 maintained contact with two steamers for a while, the contact was completely lost.  The boats, U 47, 73, and 99 which must be in the vicinity according to their reports, were ordered to proceed in the general sailing direction.  A steamer (Balistan 6,803 tons) was reported to have been torpedoed at 0515 in a Radio Intercept report.  A strict distribution of operational areas for the boats does not appear to have any point in this case.
 
 
According to U-boats reports, I.K.G.40 attacked with considerable success, at midday with one, in the evening with five aircraft.
   
27.2.
  U 73 began the return passage.  U 70 received the operational area north of U 108 (see 25.2) as far north as 610 40' North.  The concentration in the south of U 147's operational area Orkneys - Faroes was lifted.
     
      U 48 put into St. Nazaire, U 37 put out of Lorient for the south, UA put out of Heligoland for the Atlantic, U 74 put into Bergen for exercises lasting about four days.
       
      The search for the remaining steamers belonging to the convoy was unsuccessful.  Air reconnaissance did not receive the order to search for the convoy in time, and merely sighted two isolated steamers in the area of yesterday's attack.  The boats received the following orders:  U 97 to proceed to the weather reporting area, U 47 and 99 to cover the position of yesterday's attack, where there must still be some damaged steamers in the Rockall Bank area.
                                
            
    
 
 
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Date
Position, Wind, Weather
 
and
Sea State, Illumination,
Events
Time
Air Pressure, Moonlight etc.
 
 
 
 
28.2.
  U 96 and U 123 put into Lorient.
   
    From U 96's report:
  On 20.2, the boat obtained bearings on the beacon signals in both the aircraft messages, at 1050 and 1200.  Both beacon radiations indicate a position near that reported by 2 aircraft in AM 2733.  (see K.T.B. of 20.2).
   
  From this one must conclude that the first position report sent by an aircraft was incorrect, and in actual fact only referred to one convoy in the position reported by the second aircraft.  Recognition of this fact would have been of considerable value to B.d.U. the outcome of the operation would, with this knowledge, have been different.  Inference from this is as follows:
 
1) Considerable unreliability of fix must be expected in the case of aircraft messages.
2) It is impossible to operate directly on an aircraft message and assemble in the area given, rather, contact must be attempted by means of the broadest possible raking operation.  Direct operations on the enemy may be started upon only when a U-boat has established contact, thereby confirming the position of the enemy.
3) A knowledge of the U-boats bearing results, is necessary in order to check aircraft reports and the disposition of the rake.  In the future, in a case like this, the boats must report their position bearing direction, for the time being by wireless.  A simplified method is being prepared; under certain conditions by means of undecyphered wireless messages using reference points.
 
 
Apart from this, the sinking of 7 ships and 47,333 tons is a particularly fine achievement on the part of Lt. Lehmann-Willenbrock whose tenacity in maintaining contact contributed largely to the success on 23.2.  U 123 (Lt. Moehle), encountered fairly lively isolated traffic in the grid AL 42 and 51, during weather reporting duties, and sank 4 ships of altogether 33,130 tons.  The result is all the more gratifying as it was believed that the boat had encountered little, if any, traffic.  Boats must be more frequently requested to send traffic reports.
   
    U 48 had bad luck and sighted very few ships, it sank 2 ships of altogether 8,640 tons.
     
                                     (signed):  DÖNITZ
       
       
       
                            
            
    
 
 
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