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C.B.  04051 (86)
"U 523"
Interrogation of Survivors
October, 1943
This Report is not to be considered accurate in all respects, having been prepared before complete information was available.  It is therefore not to be taken as historically correct.



          This book is the property of His Majesty's Government.  
          It is intended for the use of the recipients only, and for communication to such Officers under them (not below the rank of Commissioned Officer) who may require to be acquainted with its contents in the course of their duties.  The Officers exercising this power will be held responsible that such information is imparted with due care and caution.  


Attention is called to the penalties attaching to any infraction of the
Official Secrets Acts.
C.B.  04051 (86)
"U 523"
Interrogation of Survivors
October, 1943
  N.I.D. 07015/43.  


          The following report is compiled from information derived from prisoners of war.  The statements made cannot always be verified; they should therefore not be accepted as facts unless they are definitely stated to be confirmed by information from other sources.  


  Introductory Remarks  
      (i)  General;  (ii)  Ship's Company;  (iii)  Commanding Officer;  (iv)  First Lieutenant;  (v)  Second Lieutenant;  (vi)  Engineer Officer;  (vii)  Medical Officer.    
  Details of "U 523"  
    (i)  Type;  (ii)  Displacement;  (iii)  Builders;  (iv)  Armament  (a)  Guns,   (b)  Armour Plating,  (c)  Torpedoes,  (d)  Torpedo Tubes;  (v)  Diesels;  (vi) Superchargers;  (vii)  Main Motors;  (viii) Switchboards;  (ix)  Batteries;  (x)  Welding;  (xi)  G.S.R.;  (xii)  Radar;  (xiii)  R.D.B.;  (xiv)  S.B.T.;  (xv)  Diving Performance;  (xvi)  Hydroplanes;  (xvii)  W/T Equipment;  (xviii)  Badge;  (xix)  Field Post Number;  (xx)  Flotilla;  (xxi)  Base.  
  Third and Last Patrol of "U 523"  
  Sinking of "U 523"  
  General Remarks on U-Boats  
    (i)  G.S.R. and Radar:  (ARadar.  (a)  Operational Use, (b)  Details of Equipment,  (c)  Aerial,  (d)  Future Developments.  (BG.S.R.  (a)  Details of Equipment,  (b)  Aerials,  (c)  Operational Use,  (d)  Recent and Future Development;  (ii)  Armament:  (a)  105 mm. (4.14 in.),  (b)  37 mm. (1.45 in.),  (c)  37 mm. (1.45 in.) Twin Mounting,  (d)  20 mm. (0.79 in.) Single Mounting,  (e)  20 mm. (0.79 in.) Quadruple Mounting,  (f)  Ammunition,  (g)  Gun Platform,  (h)  Armour (1)  Bridge Superstructure,  (2)  Single 20 mm. (0.79 in.) Quadruple Mounting, (j)  Training,  (k)  Radar Controlled Sights;  (iii)  Development of A.A. Defense;  (iv) Hydrophones;  (v)  Helicopter Trials;  (vi)  W/T Procedure in the Bay of Biscay;  (vii)  "Mein" W/T Receiver; (viii)  Allied Depth-charges;  (ix)  Minesweeping Escort for U-Boats;  (x)  1,200-ton U-Boats;  (xi)  New Type of U-Boats;  (xii)  U-Boat Losses.  
  Miscellaneous Remarks  
      (i)  Destroyers;  (ii)  "Scharnhorst;  (iii)  Torpedo Recovery Vessel "T.F.6;  (iv)  Minesweeping;  (v)  Dockyard Workers at Lorient.    
APPENDIX "A."  Building and Working up of "U 523"
APPENDIX "B."  Early Patrols of "U 523"
      (i)  1st Patrol;  (ii)  2nd Patrol.    
APPENDIX "C."  Nominal Roll of U-528"
      (i)  Survivors;  (ii)  Casualties;  (iii)  Total crew.  
  (C50786)                                                                                                                             B*  


         U-BOAT, SUNK BY H.M.S. "WANDERER" ON 25th AUGUST, 1943.
  (i)  General  
          "U 523," a 740-ton U-Boat, commanded by Kapitänleutnant Werner Pietzsch, was sunk at 0629 G.M.T. on 25th August, 1943, by H.M.S. "Wanderer" in position 42° 03' N., 18° 02' W.  
          She was on her third patrol when she was sunk.  She had been singularly unlucky since her commissioning in June, 1942.  Her first patrol was delayed several weeks, owing to the ramming of "Scharnhorst" during working up.  Once at sea, the only success she claimed was the coup de grâce to an 8,000-ton freighter, already torpedoed by "U 527."  Her second patrol had only lasted five days; she was heavily damaged by an aircraft attack on 24th Amy, 1943, and forced to return to base.  Further, on her third and last patrol, she had made an abortive attempt to sail on 2nd August but had to return on account of sabotage to her fuel.  She finally put to sea on 16th August, 1943.  
          A feature of particular interest in this report is additional information on Radar and G.S.R. (see Section V (i) ).  Further information on U-Boat armament is also included, from a "U 461" prisoner still under interrogation, (see Section V (ii) ).  
  (ii)  Ship's Company  
          Of "U 523's" complement of 53 there were 37 survivors.  These included the Captain, Second Lieutenant, Engineer Officer and a medical officer.  Junior ratings severely criticised their superiors for extreme lack of courage at the time of the sinking and said that the higher proportion of casualties to senior ratings was because they had left the U-Boat precipitately and were mown down by gunfire.  
          The two Chief Petty Officers to survive, respectively 26 and 28 years of age, had both joined the German Navy before the war.  The coxswain had served in the U-Boat arm since 1938.  The surviving Chief Stoker had done his U-Boat course in early 1941, having previously served in minesweepers.  The only Stoker Petty Officer had also served in a previous U-Boat.  
          Of the 30 other ratings to survive only two had served in any other U-Boat and few of them were more than 20 years old.  
  (iii)  Commanding Officer  
          Kapitänleutnant Werner Pietzsch, aged 26, had joined the navy on 1st April, 1935, just a month before his eighteenth birthday.  He was trained in "Gorch Fock."  In 1938 he was attached to the 1. Marine Artillerie Abteilung (1st Coastal Gunnery Division), he later joined torpedo boats, and his ship was sunk while escorting a convoy.  After joining the U-Boat arm, he served as officer of the watch in "U 129" under Kapitänleutnant "Niko" Clausen.  
          He was affable and well-mannered, but could not conceal from his interrogators that he was an ardent National Socialist and violently race-conscious.  He advocated the most brutal measures against the so-called "inferior" races.  
          He appeared to be a man of little imagination and was slow in the uptake.  He was evidently disliked by his ship's company and one prisoner said that although a great disciplinarian in harbour, at the time of the sinking lost his nerve altogether.  
  (iv)  First Lieutenant  
          The First Lieutenant was Leutnant zur See Waldemar Halfpap, of the 1939 term.  He did not survive and nothing is known of him.  
  (v)  Second Lieutenant  
          Leutnant zur See Alexander Cornelius Grau was the Second Lieutenant.  At the time of writing this report he was still in hospital at Gibraltar and has, therefore, not been interrogated.  
  (vi)  Engineer Officer  
          The Engineer Officer was Oberleutnant (Ing.) Walter Lorch, aged 24.  He joined the German Navy in April, 1937, and had served in destroyers before joining the U-Boat arm.  "U 523" was his first U-Boat.  
          He was uncouth and an arrant liar.  
  (C50786)                                                                                                                              B*2  


  (vii)  Medical Officer  
          The Medical Officer, Marinestabsarzt Paul Geissler, survived but was not interrogated.  It is known that in 1938 he was at the naval hospital, Wilhelmshaven, as Marineunterarzt, seniority 1st August, 1938.  Prisoners stated that he had a choice of serving at the Russian Front or in the U-Boat arm, and had chosen the lesser of the two evils.  
          Equivalent German and Royal Naval ranks used in this report are:  
Korvettenkapitän Lieutenant-Commander.
Kapitänleutnant Lieutenant.
Oberleutnant zur See Sub-Lieutenant.
Leutnant zur See Junior Sub-Lieutenant.
Oberfähnrich zur See Midshipman.
Fähnrich zur See Junior Midshipman.
Marinestabsarzt Surgeon-Lieutenant.
Marineunterarzt Medical Officer of the rank of Midshipman.
          The suffix "(Ing.)" in place of "zur See" denotes Engineer Officer, thus Oberleutnant (Ing.) = Sub-Lieutenant (E) The suffix "der Reserve" denotes a Reserve Officer.  
  Type IX C.
  Displacement 740 tons.
  Builders Deutsch Werft, Finkenwerder, Hamburg.
  Armament (aGuns.  One 105-mm. (4.14 in.) forward; two twin M.G.s 81 on bridge;  two single 20-mm. (0.79 in.) on "bandstand" and a 20 mm. quadruple mounting on additional lower "bandstand."
      There were two ready-use ammunition lockers for the quadruple 20-mm., one each side in the step between the two "bandstands."
      It was stated that the additional lower "bandstand" was built in at Lorient before the last patrol.  The original after 37-mm. (1.45 in.) gun was removed after the first patrol.  Prisoners also said that prior to the last patrol, the machine guns on the bridge had been Type 15.
      (bArmour Plating.  The bridge fairing was armoured all around at the same time as the firring of the additional "bandstand."  Two steel screen doors about 22 mm (0.86 in.) which were fitted between the bridge and the "bandstand," meeting just abaft the attack periscope.
      (cTorpedoes.  On her last patrol she carried 21.  Prisoners stated that after the first patrol two of the eight upper deck containers were unshipped.  It was agreed that six "Curly" torpedoes were carried as well as a number of Pi. 2 pistols.  The relative number of air and electric torpedoes was not cited.
      (dTorpedo Tubes.  It was stated that before her last patrol she was to have been fitted with new steel torpedo tubes in place of her bronze ones.  The latter had in any case to be removed on account of damage sustained during her second patrol.  The new tubes were not available in time, and the bronze ones were repaired and refitted.
      One prisoner said that several U-Boats are now fitted with steel tubes, on account, it was presumed, of a copper shortage.
  Diesels Two M.A.N. 9-cylinder diesels, each developing 2,200 h.p.  The Captain stated that during trials "U 523" proved to be the fastest of her series, once attaining 18.3 knots.  Another prisoner gave her theoretical maximum speed as 18.6 knots at 460 r.p.m.
  Superchargers Turbine superchargers driven through gearing ("Turbinengebläse).  The were said to make 3,500 r.p.m. and use 125 h.p.  They were connected when the diesels were running at 420 r.p.m., when they cause a temporary drop of 30 r.p.m.  The fly-wheel of these superchargers was said to weigh six hundredweight and to have a diameter of 150 cm. (59 in.).  The were said to be much quieter than the "Büchi" type usually fitted to M.A.N. diesel but not as satisfactory.


  Main Motors Siemens-Schuckert.
  Switchboards New Siemens-Schuckert.  These had small levers instead of the wheels of the older type os Siemens switchboard.  They were said to be similar to the B.B.C. make, but very much smaller.
    (N.I.D. Note.  A new type of Siemens switchboard was mentioned in C.B. 05051 (75), page 5.)
  Batteries During the air attack on the second patrol "U 523's" batteries were badly damaged, and new ones were subsequently fitted at Lorient.  These were Type M.L.A. 1,000 with a capacity of 13,000 amp./hours per battery.
  Welding Both electric and acetylene equipment carried.
  G.S.R. Metox R.600 with "magic eye" visual tuning indicator and oscillograph was fitted originally.  This was replaced before the last patrol by a "Hagenuk" receiver.  There was a drum-shaped aerial on the bridge.  Alternatively a "Southern Cross" aerial was carried as a spare, and there was a figure eight G.S.R. aerial on the back of the Radar "mattress."  (For details of the "Hagenuk" receiver, see Section V (i).)
  Radar Radar was installed before the last patrol.  A German type set was fitted in the control room and an extensible 'mattress" type aerial was fitted on the port side of the bridge.  (For further details, see Section V (i).)
  R.D.B. Two to three boxes, each containing approximately 40 balloons, stowed in the galley and control room.  Two hydrogen bottles were fitted on the bridge.  The Captain of "U 523" usually released one or two balloons at dusk.
(xiv)   S.B.T. Fitted.  It was used during the attacks prior to her sinking, when according to one prisoner, several charges were released.  He said that they were unable to use further charges on account of the pressure of water at the depth to which they had dived.
(xv)   Diving procedure The Engineer Officer claimed that she had dived to 270 metres (approximately 880 ft.) during the attack before she was sunk.
(xvi)   Hydrophones Multi-unit (G.H.G.), with normal 48 microphones on the U-Boat's bow.
(xvii)   W/T Equipment One 200-watt H/F/transmitter and one 150-watt L/F transmitter and an all-wave receiver, by Telefunken, in the W/T office.
      A 40-watt emergency all-wave transmitter and a receiver of the same type, both by Telefunken, in the listening room, as a reserve.
      A "Mein" (Lorenz) receiver was embarked before the last patrol.  (N.I.D. Note.  A "Meine" receiver was mentioned in C.B. 04051 (84) page 7.  See also Section V (vii) of this report.)
      A Telefunken radio receiver for receiving broadcast programmes was carried in the W/T office.  There were ten loud-speakers with Siemens amplifier, to enable programmes to be heard throughout the U-Boat.  Permission from the Captain had to be specially obtained.
      Aerials were the normal jumping wire and D/F loop.
(xviii)   Badge "U 523" had a red devil folding a trident painted on either side of her bow.  The flotilla badge of a large cross and a grey U-Boat was painted on her bridge.
(xix)   Field Post Number M.06935.
(xx)   Flotilla Tenth.
(xxi)   Base Lorient.
  (C50786)                                                                                                                              B*3  


          "U 523" sailed from Lorient on Monday, 2nd August, 1943, in company with "U 68," "U 123," commanded by Kapitänleutnant von Schroeter, and "U 505," commanded by Kapitänleutnant  Zschech.  They were escorted by two minesweepers, two of the U-Boats taking station astern of each.  
          As soon as the escort parted company, the group carried out a deep diving exercise. On re-surfacing "U 505" reported a serious leak.  Soon afterwards, "U 523" developed trouble with her starboard diesel, the cause of which the Engineer Officer failed to establish, although he suspected fuel sabotage.  She was also leaving an oil trace as a manhole cover had not been properly secured.  A signal to this effect was made to Control and "U 523" was ordered to return at once.  In company with "U 505" she arrived back at base the next evening.  
          Prisoners stated that "U 68" and "U 123" were both subsequently ordered to return.  "U 68" entered Lorient one day after "U 523," also reporting fuel sabotage, and "U 123" arrived some days later.  It was not known whether she also had been sabotaged.  
          As "U 523" came alongside, she was boarded by the Gestapo and all engine-room personnel were interrogated.  A laboratory test of the fuel revealed that sugar had been mixed with it, and supplies of sugar in the U-Boat were checked.  Finally the ship's company was cleared of complicity, it being presumed that the guilt lay with the dockyard personnel.  
          "U 523" spent 10 days in dock while three crankshaft bearings were changed.  Her completion was only made possible by full day and night shifts.  
        She finally sailed on 16th August, 1943.  Tropical kit was carried.  One prisoner believed she was bound for the Canary Islands area; others suggested the South Atlantic, and the Captain mentioned Brazil.  All were emphatic that her destination was not Japanese-controlled waters.  (N.I.D. NoteSee C.B. 04051 (75) Section VII.)  She was accompanied by "U 123" and escorted by a Sperrbrecher, two minesweepers and two patrol boats.  They had no air escort.  Soon after leaving Lorient a mine exploded 100 yards on the Sperrbrecher's beam.
          The group shaped course in a south-westerly direction.  The escort parted company on 17th or 18th August, leaving "U 123" and "U 523" to proceed independently.  "U 523" then continued her passage alone.  
          A number of ratings believed "U 523" was one of the first U-Boats under orders to hug the Spanish north coast and explained that the object was to provide a screen for themselves against Allied Radar by remaining within sight of Spanish fishing and merchant vessels.  On account of the strength of Allied surface craft reported by German aircraft to be in the vicinity, they thought the use of these tactics would be discontinued.  However the Captain and Coxswain flatly denied that "U 523" followed this procedure.  
          For the next few days "U 523" proceeded without incident.  About 21st August she passed the 10° W. meridian, after which the "danger area" was considered passed.  She had been ordered to signal her safe passage to Control at this juncture, but failed to do so, the Captain having intended to report about 27th August, as he considered the "danger area" to extend to 20° W.  
          "U 523's" G.S.R. was continually manned and during this patrol she was reported to have dived about five times on account of contacts.  (See Section V (i) G.S.R. and Radar.)  
          Throughout this patrol "U 523" submerged at daybreak and surfaced at dusk.  
          In the early hours of the morning of 22nd August, when "U 523" was proceeding surfaced, she was surprised by a searchlight aircraft.  No G.S.R. contact had been obtained.  The aircraft dropped bombs but the U-Boat crash-dived and escaped undamaged.  
          (N.I.D. Note.  Wellington "C" of 179 Squadron sighted a fully surface U-Boat at 0545 on 22nd August, in position 42° 59' N., 12° 49' W.  Six depth-charges straddled the target but no results were seen.)  
          "U 523" proceeded without further incident for the next three days.  
          In the early morning of 25th August, 1943, "U 523" was surfaced, having proceeded thus since dusk on the previous day.  She had no knowledge of the presence of Allied vessels and her first intimation was at about 0215 G.M.T., when the starboard look-out sighted a destroyer abeam.  G.S.R. was manned but no contact had been obtained.  The order was immediately given to crash-dive and the U-Boat was barely submerged when Asdic "ping" was heard and the first depth-charges exploded.  No damage was caused and "U 523" went to 80 metres (approximately 260 ft.) to lie low and try to shake off her pursuers.  
          (N.I.D. Note.  H.M.S. "Wanderer" attached B. One Escort Group, escorting Convoy OG92/KMS24 and Convoy "Oatmeal," obtained a Radar contact, range 14,000 yards, at 0210 G.M.T. on 25th August.  Course was altered towards.  Within a few minutes the range was reduced to  


  12,000 yards and the contact was diagnosed as "a probable U-Boat."  At 0218 "Wanderer's" A.R.L. Plot gave the U-Boat's course as 260°, speed 16-17 knots.  At 0220 the U-Boat dived at 3,200 yards.  One minute later "Wanderer" obtained an Asdic contact, range 2,100 yards, and at 0225 she dropped a pattern of 10 depth-charges, set to 50 ft. and 100 ft.  The nearest was estimated to have missed by some 40 yards.)  
          Almost immediately two further depth-charge attacks on "U 523" developed and caused slight damage.  She remained, however, at 80 metres and one or two S.B.T. charges were released after the first attack.  The second attack appeared to be further away.  
          (N.I.D. Note.  "Wanderer" released a second pattern of 10 depth-charges, set to 150 ft. and 300 ft, at 0234, and then lost contact with the U-Boat.  Meanwhile H.M.S. "Wallflower" had arrived on the scene and at 0257 dropped a 10-charge pattern, set to 50 ft. and 150 ft. but "Wanderer" could not confirm this contact.)  
         There was a lull of about an hour before a further attack developed, when depth-charges again exploded at some distance from the U-Boat.  She released further S.B.T. charges and subsequently dived to 150-180 metres (500-600 ft.).  
          (N.I.D. Note.  Contact was regained by "Wanderer" at 0302 but lost again shortly afterwards and both ships commenced a search.  At 0347 "Wanderer" regained contact and at 0351 "Wallflower" carried out an attack, with a 10-charge patters set to 350 ft. and 550 ft.  This contact was confirmed by "Wanderer" but she lost contact shortly afterwards and the explosions put "Wallflower's" asdic temporarily out of action.  After the investigation of a probable S.B.T. echo by "Wanderer" both ships commenced a search which was to last for two hours.)  
          "U 523" remained deep, proceeding at silent running speed and listening on her hydrophones as the ships above made their search.  Then, after nearly two hours, no further attacks had developed, hopes of escape began to rise.  Shortly before 0600 G.M.T., however, the Asdic "ping" was again heard and an attack was made.  There was damage in the U-Boat, the lights went out and gauges were broken.  Prisoners were vague about this attack; they said that damage was mostly aft, but did not know the number of explosions.  In the words of one prisoner, "in spite of a momentary panic, when 53 nervous men found themselves plunged into darkness, emergency lighting was soon switched on, and all damage was found to be reparable."  
          (N.I.D. Note.  At 0548 G.M.T. H.M.S. "Wanderer" regained contact.  At 0552 she carried out a hedgehog attack with depth of target estimated at 450 ft.  An explosion was heard, but it was graded as not lethal.  A signal was then made to "Wallflower" to close at full speed and it was decided to attack again without delay.)  
          Almost immediately a pattern of depth-charges exploded all round the U-Boat and everything seemed to break.  The batteries cracked, the main motors began to burn and the U-Boat started to sink by the stern.  The Engineer Officer gave the order to blow the tanks, but according to a Telegraphist "all eyes saw the depth gauge hand creep to 200 metres (650 ft.) then to 240, 250 and 270 metres (790, 820 and 880 ft.)."  He said that wood splintered and steel bent; the pressure hull groaned, but held.  There was considerable water entry.  An attempt was made to release a further S.B.T. charge, but the pressure of the water was too great.  The Engineer Officer repeated his order and the U-Boat slowly rose, back to 200, to 100 and to 20 metres.  As she broke surface the noise of gunfire was heard.  
          (N.I.D. Note.  At 0602 "Wanderer" dropped a 16-charge pattern, set to 500 ft. and 550 ft.  She prepared for a further attack, but at 0609 the U-Boat;s bow broke surface almost vertically, 1,200 yards on the port beam.  Fire was opened with every available gun.  Several direct hits were obtained and the U-Boat's crew started to abandon ship.)  
          Several of the Petty Officers and Leading Hands had crowded into the conning-tower behind the Captain and First Lieutenant.  As the hatch was opened, the bridge was raked with fire and the men upon it killed.  It took the remainder of the ship's company some minutes to clear the conning tower hatch and escape, and some left the boat by the after hatch.  One man attempted to man the 20-mm. quadruple mounting, but was deterred by "Wanderer's" tracer fire and jumped overboard instead.  
          Prisoners stated that "U 523" was not scuttled.  She remained afloat for about 10 minutes and then sank by the stern.  
          (N.I.D. Note.  "U 523" was observed to sink on an even keel at 0629.  Position was given as 42° 03' N., 18° 02' W.)  
  (C50786)                                                                                                                              B*4  


  (i)  G.S.R. and Radar  
          The information concerning latest developments given below was largely obtained from the two Leading Telegraphists from "U 523" and a Leading Telegraphist from "U 135."  
         (A)  Radar  
          "U 523" was equipped with the latest type of U-Boat Radar, manufactured by Gema.  It was stated that similar sets are being made by Siemens and Lorenz.  
          (N.I.D. Note.  The first U-Boat fitted with Radar of a different type, from which prisoners were captured was "U 187."  See C.B. 04051 (60), page 3.)  
          One leading Telegraphist from "U 523" had done a general four-week Radar course at Le Coq early in 1942, but neither of them had any recent instruction.  
          All U-Boats are probably to be fitted with Radar, which will be of the new type mentioned above.  The frontal array type as fitted in "U 187" was removed from the few U-Boats so fitted.  (N.I.D. Note.  It has not been noticed in recent U-Boat photographs.)  The Captain of U 523," however, expressed extreme lack of confidence in his Radar.  
          (aOperational Use.  Radar was said only to be intended for locating or maintaining contact with surface craft, particularly convoys at night, and was not for detecting aircraft, the G.S.R. being meant to take care of the latter.  
          Radar and G.S.R. could not be used simultaneously, as the G.S.R. reception was swamped.  
          Radar could be used for torpedo firing.  The method was to obtain the bearing and range of the target, and then note the change of bearing and range against a stop watch, thus enabling a plot to be made of the target's relative course.  (N.I.D. Note.  It is unlikely that the aerial array, mentioned below, would give an accurate bearing.  The use of radar for torpedo firing was mentioned in C.B. 04051 (60), page 12.)  
          The range of the set was said to be 7-10 km. (3.8 to 5.4 miles) against surface targets, depending largely on the sea running.  No evidence could be obtained as to the range at which aircraft could be detected, since the set was never used against them.  
          (bDetails of Equipment.  The U-Boat Radar wavelength is exactly 80 cms. (375 mc/s) and all U-Boats work on the same one.  (N.I.D. Note.  This corroborates statements by prisoners from "U-607."  See C.B. 04051 (74), page 3.)  
          The set carried by "U 523" had a P.R.F. of 500 impulses/second, and was described by the operators as being very complicated.  The receiver was a box about 6.5 ft. by 3.3 ft. by 5.9 ft.  There were about 16 control knobs.  The method of presentation was on a green C.R.O. screen with horizontal trace. When a contact was obtained a blip was seen and brought on to the centre line of the tube by means of a coarse and fine control.  The distance of the target was read off two tachometric scales, the coarse reading in thousands of metres, the fine in hundreds.  The bearing of the target could be obtained to about plus/minus 5° by rotating the aerial by hand.  
          The maximum voltage used in the set was 8,000, which was obtained from a rotary converter.  The greatest voltage across any valve appears to have been 2,000.  The output stage was said to take an R.M.S. current of 30-32 ampères at 2 volts.  
          (cAerial.  The type of aerial carried was a mattress, housed, when not in use, in the bridge fairing on the port side, in the place previously used for extensible W/T aerial.  (N.I.D. Note.  A similar aerial was described by prisoners from "U 607," see C.B. 04051 (74), page 3, and from "U 506," see C.B. 04051 (75), page 5.)  It was raised and lowered by compressed air and was often out of order.  It was stated that if a U-Boat dives with the aerial extended, damage will be done to it in about 20 per cent of all cases; if however, an attempt is made to align and withdraw the aerial when submerged, then it will invariably be damaged.  
          The aerial itself was 120 cm. by 80 cm. (47 in. by 31 in.), the reflector being of wires forming squares of 20 cms. (7.92 in.) wide.  There were six dipoles, 10 cms. (3.9 in.) long, the top four being used for transmission, the bottom two for reception.  These were mounted at 45° to the vertical.  
          On the back of the aerial was a figure of eight loop, used as a standby aerial for the G.S.R., and having no connection with the Radar aerial.  
          (dFuture Developments.  The Captain of "U 523" said that "Rotterdam" and "Berlin" equipments had been mentioned during a lecture on future Radar developments.  He compared these equipments with the Würzburg and Lichtenstein sets already in use by aircraft and ashore, but knew nothing further about them.  (N.I.D. Note.  Würzburg is Type B or B(2) German shore Radar (see C.B. 03067/43.)  Lichtenstein is used for various types of airborne Radar including a German equivalent of A.S.V.)  


        (B)  G.S.R.
          U-Boat Captains rely very largely on their G.S.R. reception to give warning of the approach of aircraft and surface vessels.  "U 523" was delayed a week before sailing on her last patrol, while waiting for the latest type to be built in.  Despite this reliance, however, "U 523" was attacked on her last patrol by a searchlight aircraft which had not been detected (see Section III), and she was finally sunk by surface craft of which the G.S.R. had given no warning (see Section IV).  Blame was on the whole laid on the shoulders of the operator rather than on any shortcomings of the set itself, despite the fact that at a demonstration given in Lorient on 12th August, mention was made of forthcoming improvements and attempts to increase the waveband covered.  (N.I.D. Note.  There was a previous case of the operator being blamed for the shortcomings of the set, see C.B. 04051 (75), page 5.)  
          "U 523" was believed to have been one of the first U-Boats fitted with a new type of G.S.R.  It was made by the Hanseatische Apparatenbau Gesellschaft, Neufeldt und Kuhnke, known as "Hagenuk," at Kiel.  It was also referred to as WANZ (Wellenanzeiger).  One prisoner, however, said that WANZ is a cover name for all G.S.R. and Radar equipment.  
          (aDetails of Equipment.  The great advantages of the set were said to be that there was an automatic scanning mechanism, covering the whole waveband between 14 and 24 times per second, and that it did not radiate.  The chief disadvantage was that the waveband covered was only from 120 to 180 cms. or possibly 200 cms., whereas the Metox R.600 and R.600A sets previously carried covered the waveband from 60 to 220 cms.  One Telegraphist said that 30 cm. Radar would be detectable on the third harmonic, and another prisoner stated that reception of shorter wavelengths was possible visually, but not aurally.  Other more knowledgeable prisoners knew nothing of this possibility.  
          The set was housed in a box 18 in. deep, whose front panel was about 18 in. by 16 in.  In the middle was a C.R.O. tube, to the right of which was (from bottom to top) the focusing control, brilliancy control and coarse and fine wavelength measurement controls.  The latter was fitted with tachometric scales, the coarse scale reading to the nearest centimetre.  (N.I.D. Note.  A greater accuracy than 1 cm. would appear to be unnecessary.)  To the left of the C.R.O. tube was the time base control and gain control, while over the tube was the set's on-off switch.  
          The C.R.O. tube was about 4 in. in diameter with a green field.  Across the centre was a horizontal opaque strip graduated to show wavelength in centimetres.  
          It was a five valve set, the three valves in the input side being Ph. 6461 and one of the amplifier valves an R.V.2.P. 2,000; i.e., amplifier valve 2-volt filament Pentode mu = 2,000.  
          There was no means of distinguishing between horizontally and vertically polarized transmissions as in the Metox receivers.  
          (bAerials.  Three separate aerials were carried in "U 523" for use with this set:  
                  (i)  Drum or basket type ("Runddipol").  This has become the standard built-in G.S.R. aerial and was mounted on the port side of the bridge forward of the Radar mattress.  It consisted of a cylindrical wire mesh, about 9 in. diameter and 4 in. high, divided vertically into two halves by mica insulators.  (N.I.D. Note.  This agrees with the dimentions given in C.B. 04051 (74), page 3.  The type was first mentioned in C.B. 04051 (68), page 3.)  On the top of each of these two insulators there was a rod, about 8 in. long, each rod being connected to one half only of the mesh.  The connecting cable passed through a watertight gland into the pressure hull.  
                  This aerial was normally used, but if it was out of order, either of the other following types could be used.  
                  (ii)  Southern Cross ("Kreuz des Südens"): this was as previously described and had the great disadvantage of a cable through the conning-tower hatch. (N.I.D. Note.  This aerial was originally described in C.B. 04051 (55), Section IX (i) (a).)  
                  (iii)  A figure of eight aerial mounted at the back of the Radar aerial.  
          (cOperational Use.  Searching was done automatically until a contact was made (see Details of Equipment above) and visual watch was kept.  A contact was indicated by a faint blip at one point on the trace and the operator would immediately warn the officer of the watch and go over from automatic to manual search, the wavelength from which to start being given approximately by the scale on the C.R.O. tube.  In addition to visual search, he also put on headphones, useless when the automatic scanner was running, in which a note was heard on tuning to the wavelength being received.  When the automatic scanner was switched off, the line trace across the tube contracted to a point of light whose position on the screen depended on the turning of the set.  When the set was tuned accurately to the wavelength being received the spot grew to a vertical blip of up to 7/8 in. in high.  The wavelength was then read off the dials at the top right of the set and logged.  
          "Mush" reception, such as that cause by the electric apparatus on board, could not be mistaken for a real contact, since it caused blips to appear below the trace on the return path of the spot.  
          The set appears to have been fairly reliable except for the frequent burning out of an R.V.2P. 1,000 amplifier valve.  This occurred seven or eight times between "U 523's" sailing on her last patrol on 16th August and her sinking on 25th August.  


          G.S.R. watches were normally two hours.  It was stated that to relieve the strain on W/T personnel, L.T.O.s are now also trained to keep G.S.R. watches.  This however, leads to neglect of the torpedo overhaul routines especially when the bulk of the torpedoes are electric, which require more attention than air torpedoes.  
          (dRecent and Future Development.  In early August, 1943, orders were issued by Control that only "Hagenuk" sets might in future be used, since it was believed that we could detect radiation from the other types of set in existence.  
          (N.I.D. Note.  Prisoners from "U 489" and "U 468" stated that they had received orders forbidding the use of G.S.R. in the Bay of Biscay, during their last patrols.  See C.B. 04051 (84), Section V (iii), and (85), Section II (viii), respectively.)  
          The Captain of "U 523" said he had heard that the wavelength range of the Hagenuk receiver might shortly be extended down to 60 cms.  
  (ii)  Armament  
          (a105 mm. (4.14 in.).  The A.A specialist from "U 461, still under interrogation, said it was rumoured that all 105-mm. guns were being removed from U-Boats for coastal defense in case of invasion.  
          This gun was not unpopular with gun's crew, but the great difficulty was the ammunition problem.  Sixty rounds were carried in containers flush with the upper deck, thirty on each side of the gun.  He gave the maximum range in practice as 12,000 metres (about 13,000 yards), but said that accurate range was not much more than 5,000 metres (5,500 yards approx.); minimum range was 1,500 to 1,600 meters (1,640 to 1,750 yards).  (N.I.D. Note.  Prisoners from "U 506" stated that the range of this gun was 15 kms. (about 16,000 yards), see C.B. 04051 (75), Section V (i) (a).)  
          This prisoner stated that a number of 105-mm. guns had been adapted as H.A. guns, making possible an elevation of 80-85° instead of the former 50-60°.  
          He also mentioned special A.A. ammunition for this gun, known as "105-mm. Flak Granat."  The nose fuse was set by a triangular key.  Range was estimated.  Splinter effect was 25 metres (82 ft.) maximum, with an estimated lethal range of 10 metres (33 ft.).  (N.I.D. Note.  This appears to be similar to an ordinary H.E. shell.)  
          (b37-mm (1.45 in.) Gun.  The same prisoner stated that the normal practical rate of fire with the 37-mm was 40/50 rounds per minute, although a crack crew under training conditions might reach 72 rounds per minute.  A gunner would not expect to get off more than 10 rounds during any one aircraft attack.  
          (N.I.D. Note.  The above performance seems reasonable.  A theoretical rate of fire of 80 rounds per minute was give in C.B. 04051 (81), Section V (i) (1).  A detailed description of this gun was given in C.B. 04051 (74), page 7.)  
          He added that instruction at the U-Boat A.A. School at Nest had included a type of barrage with the 37-mm gun.  Shots were placed as far as possible in a pattern, 10-15 meters broad by 10 metres deep (33-49 ft. by 33 ft.), along the line of flight of the aircraft.  Barrage firing might be employed down to 1,000 metres (1,093 yards) range.  
          (c37-mm (1.45 in.) Twin Mounting.  Another prisoner under interrogation stated that while on an A.A. course at Biarritz he had received instruction on the 37-mm. mounting.  The effective rate was slower due to hand-loading.  Every effort during training was directed towards making the two loading numbers so efficient that both barrel fired simultaneously.  The gun's crew consisted of eight.  
          (N.I.D. Note.  This gun is referred to in C.B. 04051 (74), page 8.)  
          (d20-mm (0.79 in.) Single Mounting.  The prisoner from "U 461" gave the practical rate of fire for the C.38 20-nm.single mounting as not more than 3-4 rounds per second.  The clips were self releasing as the last round was fired and it took only one or two seconds, according to the deftness of the loading number, to fit a new one.  
          He said he would expect to fire 10-15 rounds in a burst, so that each clip would give a possible two bursts.  There would be a second or so interval between the bursts, during which time the gunlayer was correcting his aim.  He thought a U-Boat gunner would be doing very well to get off 40 rounds during one aircraft run-up.  
          (N.I.D. Note.  Prisoners from "U 506" gave the rate of fire of this gun as theoretically 400 rounds per minute, in practice 200; see C.B. 04051 (75), page 4.  Other details of this gun were give in C.B. 04051 (74), page 2.)  
          (e20-mm. (0.79 in.) Quadruple Mounting.  The same prisoner estimated that the maximum number of rounds which could be fired in any one run-up by an aircraft would be 40 per barrel, with a well-trained crew.  (N.I.D. Note.  Prisoners from "U 607" mentioned a rate of fire of 60 rounds per minute per barrel; a total of 240 rounds per minute;  see C.B. 04051 (74), page 2.)  


          He said that five or six turns of the elevating wheel would give full elevation.  (N.I.D. Note.  See also C.B. 04051 (74), page 2.)  According to this prisoner, one of the gun's chief weaknesses was the cable arrangement of this elevating gear wheel, as it is far too easily shot away.  (N.I.D. Note.  See also C.B. 04051 (81), page 4.)  He said he had seen a new type, using telescoping rods in place of this cable.  
          (fAmmunition.  The same prisoner from "U 461" stated that, at the time of his capture tracer was fitted to H.E. but not to H.E./A.P.  He believed, however, that trials with tracer H.E./A.P. had already been made that it would soon be in operational use.  
          He explained that the extensive use of self-destroying ammunition in U-Boats was due to its original manufacture for use on land.  He added that Oerlikon ammunition was not self destroying.  
          (N.I.D. Note.  Further details on ammunition, given by the same prisoner, are recorded in C.B. 04051 (81), page 9.)  
          (gGun Platform.  He compared the two types of additional lower gun platform and was much more enthusiastic about the one built about six feet clear of the "bandstand" and connected by a cat-walk.  (N.I.D. Note.  This was fitted in "U 462," see C.B. 04051 (82), page 1.)  
          He said it was designed by Blohm and Voss.  He maintained that it allowed more freedom of movement for the gun's crew and that the ammunition supply was facilitated.  The cat-walk had raised sides and ammunition clips could quite easily be slid down it, thereby avoiding passing them from hand to hand.  
          (hArmour.  (1)  Bridge Superstructure.  The same Flak specialist from "U 461" maintained that armour extends right around the bridge, except for the forward breakwater, which is unprotected.  (N.I.D. Note.  This corroborates a statement by prisoners from "U 706" who said that there was no armour plating forward, see C.B. 04051 (80), page 1.  Prisoners from all other recently sunk U-Boats have, however, mentioned all-around armour plating on the bridge superstructure.)  
          He added that the two steel screen doors fitted between the bridge and the "bandstand" have not proved satisfactory.  Cases had been known of one round through a hinge jamming the door hopelessly.  It was also customary in action to shut one door, which made passage to and from the bridge and the "bandstand" extremely difficult.  (N.I.D. Note.  These steel  screen doors were first mentioned in C.B. 04051 (74), page 3.)  
          (2)  Single 20-mm. (0.79 in.).  The same prisoner remarked that the most vulnerable were the crew of the single 20-mm. on the "bandstand."  A few U-boats had short strips of armour plate fitted to these guns, giving them breast protection.  The right-hand strip was 20 cm. broad by 30 cm. high (7.9 in. by 11.8 in.) and the left-hand strip 8/10 cm. broad (to allow for the ammunition clip) and 30 cm. high 3-4 in. by 11.8 in.).  He did not think it was much use and said that the greater proportion of casualties were wounded in the feet and legs.  
          (3) 20-mm. (0.79 in.) Quadruple Mounting.  This prisoner knew of two types of armour for 20-mm. quadruple mountings.  The first type, as in "U 461", consisted of two plates welded together, the top half being 5 mm. (.2 in.) thick and the lower half 7.5-10 mm. (.3-.4 in.) thick.  There was also a plate 7.5 mm. (.3 in.) thick to the right of the front armour at about breast height, said to be 30 cm. (11.8 in.) long and 20 cm. (7.9 in.) broad.  The complete shield extended merely 180 cm. (approximately 6 ft.) above the upper deck with the upper portion slightly curved back to give overhead protection.  (N.I.D. Note.  The height and shape of this shield is confirmed by photographic interpretation.)  
          The second type was a shield of uniform thickness throughout.  He had seen a number of boats so fitted at Bordeaux.  
          (j) Training.  The prisoner mentioned in (ii)c above who had attended the first three weeks of a Flak course at Biarritz, gave some information on his training there.  About 50 per cent of the trainees were from U-Boats, and the other half from surface ships.  Many of these ratings, including the prisoner himself, were stokers, who had been detailed as A.A. gunners on account of recent heavy casualties to seamen gunners.  
          The 37-mm. (1.45 in.) twin mounting and the 20-mm. (0.79 in.) single mounting were the only guns on which the prisoner had been trained, but there were also 37-mm. single mountings and 20-mm. quadruple mountings at the school.  
          He said that all training was carried out with a "Flak" sight and no open sight shooting was practised during the time he was at the course, although guns were fitted with open sights which cloud be brought into use.  He called the sight used a "Flak Sight Z," and said it was a reflector type with illuminated graticules.  It required speed and aircraft course as well as range to be set into it.  The maximum range at which it could be used was 2,800 metres (about 3,000 yards) and the minimum 100-150 metres (109-164 yards).  He considered it complicated to use and stated that the opinion of the school, even that openly expressed by the instructors, was that gunners would do much better to ignore it and that it was just a gadget which had to be kept polished for inspection by senior officers.  


          The prisoner from "U 461" said he knew this sight, but was confident that it would not be used in U-Boats because it would rust far too easily, especially in the computing drum.  
          (N.I.D. Note.  Details on A.A. training have previously been reported as follows:  
                  "Flak" School at Mimizan (South France):  C.B. 04051 (68), pages 7-9.  
                  "Flak" School at Mimizan (South France):  C.B. 04051 (70), page 6.  
                  "Flak" School at Mimizan (South France):  C.B. 04051 (81), page 9.  
                  "Flak" School at Misdroy:  C.B. 04051 (71), page 5.  
                  "Flak" School at Misdroy:  C.B. 04051 (74), page 8.  
                  "Flak" School at Swinemünde:  C.B. 04051 (74), page 8.  
                  "Flak" School at Nest, near Berlin:  C.B. 04051 (81), page 8.  
                  "Flak" School at Köslin:  C.B. 04051 (82), page 5.)  
          (kRadar controlled Sights.  The prisoner from the "Flak" course at Biarritz, stated that the next course there was to receive training on Radar sighting of 20-mm (0.79 in.) weapons.  
          (N.I.D. Note.  This presumably only implies that the sight will be fed with Radar range and not that the enemy is contemplating blind fire by these weapons.)  
  (iii)  Development of A.A. Defense  
          One leading Telegraphist discussed the development of German A.A. defense in U-Boats since the autumn of 1942, when the High Command realised that some new way of combating aircraft had to be devised.  Trials by experienced U-Boat Captains proved that it was useless to dive to escape an aircraft, if the aircraft was near enough to attack before the U-Boat could reach 80 metres (approximately 260 ft.).  
          Consequently, in November, 1942, the first U-Boat with an additional lower "bandstand" was put into service.  She was "U 553," commanded by Kapitänleutnant Thurmann, attached primarily to the 7th Flotilla at St. Nazaire and later to the 3rd at La Pallice.  After trials, Thurmann reported against this additional "bandstand."  He stated that it stiffened the hydroplane controls at a depth of 15/17 metres (50-55 ft.) and gave such a big wave that it decreased the chances of success in periscope depth convoy attacks.  
          This difficulty was to some extant alleviated, by holes being made in the base of the additional "bandstand."  
          At the same time "U 594," commanded by Korvettenkapitän Munn, made similar trials and Munn reported in favor of it.  
          On Dönitz' order, six U-Boats in St. Nazaire were then also fitted, and 20-mm (0.79 in.) quadruple guns were mounted.  
          In the course of this development of A.A. defense, the prisoner told how "U 511" and "U 513" were the first two boats to be ordered to proceed through the Bay of Biscay with an air escort of Ju. 88s and categoric instructions not to dive in the Bay at all.  
          He mentioned also that during July, 1943, the U-Boat commanded by Kapitänleutnant  Mengersen sailed from St. Nazaire with her newly fitted 20-mm. quadruple mounting on an additional "bandstand" and fought off eight aircraft, one of which was shot down.  A personal signal of congratulation was sent by Dönitz.  (N.I.D. Note.  This presumably refers to "U 607" previously commanded by Mengersen, but latterly taken over by Jeschonnek, which was sunk by aircraft on 13th July, 1943, see C.B. 04051 (74).)  
          Another prisoner stated that the first U-Boat to be fitted with a 20-mm. quadruple mounting was "U 758," commanded by Manseck.  He claimed that she was attacked by nine aircraft and shot down six.  
          It was further stated that all U-Boats of the 2nd, 7th and 10th Flotillas are now equipped or being equipped with 20-mm, quadruple mountings on the additional "bandstand."  
          (N.I.D. Note.  The first U-Boat so fitted from which prisoners were captured was "U 528," see C.B. 04051 (71). Section II.  A.A. defense was discussed at length by prisoners from "U 175" and "U 607," see C.B. 04051 (68) and (74), Section V.)  
          The Captain of "U 523" had a very healthy respect for aircraft.  When asked what he considered the extent of the Bay of Biscay "danger area," he stated that although the Bay of Biscay was by far the most dangerous area, he considered nowhere in the North Atlantic free from aircraft.  With aircraft carriers continually patrolling from the Azores to Bermuda, he remarked that north of the 20° Northern parallel as far as Greenland was completely covered by daylight aircraft patrols.  
          He said that U-Boat Captains now proceed through the Bay of Biscay at their own discretion, having received the current operational dispositions.  They cannot, however, chose the time of day at which they sail on account of the arrangements for escort, which usually cause the Flotilla S.O. considerable telephonic communication.  The first diving exercise is made at the 200-fathom line and he said that aircraft had seldom recently been seen nearer to the coast than this.  Most U-Boat Captains had reverted to the policy of submerging by day and remained on the surface at night in the Bay.  He, himself, only surfaced in daylight there when there was maximum visibility.  


          He expressed considerable satisfaction over the fact that a Squadron of Me. 110 aircraft had recently arrived at Vannes.  He said that they had orders to fly an armed reconnaissance on a general course north-westwards as far as Ireland.  
          In spite of all this German anti-aircraft development, he stated his belief that the U-Boat arm is no longer of use in any area where it is possible to provide complete air cover.  
  (iv)  Hydrophones  
          A Telegraphist gave the following figures for the operational range of the hydrophones:  
Single ships
8-11 nm
12-15 miles. (In the case of a large ship, such as a cruiser of a 10,000-ton m.v.)
6 miles
10 miles.
12 miles.
20 miles.
          He mentioned "U 523's" failure to pick up "Scharnhorst" on her hydrophones before she rammed her (see Appendix "A").  He said, however, that it was officially agreed that neither the hydrophones nor the operator was to blame, as "Scharnhorst" had been lying stopped until a moment before the accident.  He added that two or three days after this incident, another U-Boat passed within 300-400 yards of "U 523" without being detected, and believed his hydrophones had been affected by the density of the water in the Baltic.  
          In the latter connection, it was stated that of the above figures for ranges, the maximum figures were a good guide for the Atlantic, while in areas such as the Baltic, the average figures were more correct.  
  (v)  Helicopter Trials  
          During August, 1942, while "U 523" was working up in the Baltic (see Appendix "A"), she carried out trials with a helicopter type of kite.  
          Prisoners stated that a platform, about 6 ft. by 3 ft., was built on the bridge superstructure.  The helicopter was embarked in cases and assembled at sea.  "U 523" was escorted by a torpedo boat and two destroyers, and staff officers, including an Army General were present, sometimes in the U-Boat and sometimes on board the escorts.  
          The helicopter was said to have one set of blades mounted about a vertical axis and a rudder of wooden framework, covered with some cloth material.  The pilot sat on a seat, similar to a bicycle saddle, inside the framework.  The whole was square in shape.  
          It was released on a cable running from a motor-driven winch on the special platform and normally veered to a height of about 100-250 ft.  "U 523" proceeded at full speed.  Communication from the helicopter to the U-Boat was by V.H/F, the pilot carrying his receiver/transmitter packed on his back.  
          Another prisoner from "U 468" stated that, while serving with a torpedo recovery vessel about mid-August, 1943, before joining "U 468," he had carried out similar trials in Danzig Bay with a 500-ton U-Boat.  
          It was, however, generally agreed amoung prisoners, that these trials had not been very successful.  
  (vi)  W/T Procedure in the Bay of Biscay  
          The Captain of "U 523" stated that all U-Boats have now been ordered to observe complete W/T silence, except for one signal to be made on completion of the passage of the Bay.  This was intended to be made on reaching the 10 W. meridian, but he considered 20° W. to be the end of the danger area.  
          A rating prisoner stated that when returning through the Bay of Biscay, E.T.A. is signalled about two days in advance and the state of fuel and torpedoes has to be reported before final permission to return is granted.  
  (vii)  "Mein" W/T Receiver  
          Prisoners stated that the "Mein" receiver carried in "U 523" was an improved super heterodyne crystal receiver, with a far greater sensitivity than the previous types.  One leading telegraphist was amazed at the reception obtainable in the shelters at Lorient.  
          It was alleged that this receiver did not suffer from the defect of previous types, which were said to radiate and to be easily detected.  (See also Section II (xvii).)  


  (viii)  Allied Depth-Charges  
          A prisoner from "U 461," still under interrogation, stated that he had been officially told that a depth-charge dropped up to 50 meters (164 ft.) on the beam would be lethal.  Although at the extreme range it would not crack the pressure hull, outer tanks were liable to be so damaged as to leak and give away the U-Boat's position if submerged.  He added that Commanding Officers try to keep stern on to attacking aircraft, not only in the case of aircraft this brings the heaviest armament to bear, but also because the stern is considered the least vulnerable to depth-charge attack.  
  (ix)  Minesweeping Escort for U-Boats  
          The Captain of "U 523" stated that U-Boats leaving port are proceeded by an escort of "Sperrbrecher" which sweep for moored mines up to a depth of 25 fathoms.  
          The latest orders are that not more than two U-Boats may follow one "Sperrbrecher," and the distance between the two U-Boats must not exceed 50 metres.  
  (x)  1,200-ton U-Boats  
          It was stated that 1,200-ton U-Boats have unusually large W/T offices, with extensive equipment.  Among other sets carried on board this class, a prisoner mentioned:  
                  An "automatic" transmitter.  
                  Two large surface unit type receivers.  
                  Two short-wave receivers.  
                  One long-wave receiver.  
  (xi)  New Type of U-Boats  
          Prisoners from "U 523" mentioned the new type of small U-Boats with a different form of propulsion believed to be turbines.  They claimed that "U 523" had carried out diving tests with one of these U-Boats in the Baltic.  They said that after one dive, "U 523" surfaced and never saw the other U-Boat again; they believed that owing to her greater underwater speed, she had surfaced out of sight.  A speed of 30 knots submerged was mentioned.  
          One Prisoner was drafted to the Deutsche Werke, Kiel, to an 18-man U-Boat.  It was understood that no one below leading rate would serve in these U-Boats.  Shortly before he was due to leave the drafting was cancelled and he said that he had heard that the type was not proving satisfactory.  
          (N.I.D. Note.  Prisoners from "U 706" mentioned 15-man U-Boats, see C.B. 04051 (80), page 4).)  
  (xii)  U-Boat Losses  
          The Captain of "U 523" discussed U-Boat losses, which he admitted had already exceeded the last war figure of 199.  Of the 10 U-Boats, "U 520" to U 530," he said only "U 525," commanded by Kapitänleutnant Drewitz, remained.  Further he stated that since the formation of the 10th U-Boat Flotilla in 1942, it had lost 27 U-Boats, excluding his own.  The flotilla strength was normally 20 U-Boats.  
          A rating said that during June, 1943, there were only four U-Boats in the Lorient Base.  
  (i)  Destroyers  
          The Engineer Officer from "U 523" had served in destroyers from before the war until 1940, at one time under Johannesson.  
          (N.I.D. Note.  Kapitän zur See Rolf Johannesson was subsequently Captain of the ex-Greek destroyer "Hermes," scuttled in Tunis harbor on 7th May, 1943, after he had left her.)  
          Lorch stated that his destroyer had Benson type boilers which had presented certain teething troubles, being the first of their type but had given good service.  He indicated that their steam working temperature had been something over 500C. (1,060F.).  
  (ii)  "Scharnhorst"  
          According to one prisoner, "Scharnhorst" rammed a buoy in harbor the day after the incident with "U 523" (see Appendix "A").  He said that on this account the Captain was relieved.  
          (N.I.D. Note.  Kapitän zur See Kurt Hoffmann was in command of "Scharnhorst" from 1940 to 1942.  He was promoted to Rear Admiral in April, 1942, but it is not known at what date he actually relinquished his command.  This story might refer to a subsequent Captain.)  
  (iii)  Torpedo Recovery Vessel "T.F.6"  
          "T.F.6" of the torpedo recovery flotilla and attached to the U-Boat firing flotilla at Danzig, was rammed by "U 528" and sank.  She was subsequently raised and towed into Danzig on 1st July, 1043.  (N.I.D. Note.  This incident was mentioned in C.B. 04051 (71) Appendix "A" (ix).  Prisoners from "U 528," sunk on 11th May, 1943, said that it occurred on 8th or 9th January, 1943.)  


  (iv)  Minesweeping  
          One prisoner said that minesweeping from Lorient was carried out by about five M-Class sweepers (M-Booten) of the latest type.  Whenever enemy aircraft had been reported in the area minesweepers went out in the morning at about 0900 and returned at about 1300.  In addition, one Junkers 52, fitted with a magnetic sweep, went out every morning; and two if an air-raid warning had been sounded anywhere over France the previous night.  
  (v)  Dockyard Workers at Lorient  
          Naval dockyard workers at Lorient consisted of technicians of all ages, some of whom had already served in Russia.  They wore a blue uniform and cap, and were accommodated in evacuated houses and hotels at Hennebont, about 10 km. North East of Lorient.  There was said to be heavy bus and train traffic bringing these men to work every morning.  The workers included about 5,000 Frenchmen.  
          The Todt organization in Lorient was said to include some very old men from Germany, and also some Spanish Republicans.  One of the latter was said to have killed a U-Boat Leading Stoker in a public house in Lorient.  





          "U 523" was built at the Deutsch Werft, Finkenwerder, Hamburg, and commissioned on 26th June, 1942.  She passed the trials of the U-Boat Acceptance Command at Kiel and proceeded to the Baltic for working up.  
          In early August, 1942, she carried out trials with a helicopter, proceeding to sea with a torpedo boat and two destroyers.  (For details see Section V (v).).  
          She then joined a group of U-Boats undergoing tactical exercises with "Scharnhorst," during an inspection by Admiral U-Boats.  During the operation "U 523" surfaced too close to "Scharnhorst" and rammed her, sustaining considerable damage to her bows.  Prisoners said the battle-cruiser had been lying stopped and had started up her engines just after the order to surface had been given in "U 523," so that the hydrophone operator was not to blame.  (See also Section V (iv).)  
          "U 523" put into Danzig for repairs about the end of August and lay in dock for four weeks.  At the end of September she proceeded once again to the U-Boat Acceptance Command at Kiel, and thence to the Baltic to work up afresh.  She may also have rammed another 500-ton U-Boat and have undergone a further period in dock for repairs.  
          In December, 1942, she returned to Hamburg for final adjustments.  She sailed for Kiel at the end of January, 1943.  
  1st Patrol  
          "U 523" sailed from Kiel on 9th February, 1943, escorted by minesweepers and aircraft.  She called at Kristiansand S. for one night and spent the next night at Egersund.  One prisoner stated that she was accompanied as far as Egersund by a 1,200-ton U-Boat.  He said that their escort consisted of two Sperrbrecher, with two minesweepers proceeding ahead of the group.  Thence "U 523" proceeded alone along the Norwegian coast and across the North Sea to the "Rosengarten."  She then entered her operational area in the North Atlantic.  
          During an attack on an east-bound convoy about mid-March, she fired one torpedo at an 8,000-ton freighter, which was badly damaged.  Prisoners explained that this ship had already been attacked by "U 527," commanded by Uhlig, and that the crew had abandoned ship before "U 523's" attack.  Admiral U-boats credited "U 527" and "U 523" each with 4,000 tons.  
          (N.I.D. Note.  This incident was mentioned by prisoners from "U 527," interrogated in the United States.  It has not been possible to identify the attack.)  
          Before returning to base, "U 523" was refuelled.  With three other U-Boats she rendezvoused with "U 462," commanded by Oberleutnant zur See der Reserve Vowe, in broad daylight.  "U 523" took over 22 tons of fuel and some bread.  A few days later she met "U 463," commanded by Korvettenkapitän Wolfbauer, and embarked G.S.R. equipment, including a "Southern Cross" aerial.  
          She headed for base and arrived in Lorient on 16th April, 1943.  
  2nd Patrol  
          "U 523" left Lorient on 22nd May, 1943.  At 1128 on 24th May, 1943, she was attacked by an aircraft.  
          (N.I.D. Note.  Bomber Command Whitley "J" of 10 O.T.U. Squadron attacked a U-Boat at 1122 on 24th May, 1943, in position 46° 26' N., 9° 25' W.  Six 250-lb. Torpex depth-charges were dropped.)  
          In "U 523" there was damage to No. 8 main ballast tank and to No. 7 main ballast (emergency fuel) tank.  The batteries were out of order and the lights went out.  Prisoners also mentioned the bending of three torpedo tubes and the jamming of one of the forward watertight doors.  The latter imprisoned two ratings, who could not be released until two days after the U-Boat had reached base.  
         "U 523" arrived back in Lorient on 26th May, 1943.  She went into dock for the repairs necessitated by the aircraft attack.  Subsequently she was fitted with her additional lower gun platform and 20-mm. (0.79 in.) quadruple mounting and the bridge fairing was armoured.  (See Section II.)  


          (i)  Survivors:  
English Equivalent.
Pietzsch, Werner Kapitänleutnant Lieutenant 30. 4.17
Grau, Alexander Leutnant zur See Junior Sub-Lieutenant 16. 9.19
Lorch, Walter Oberleutnant (Ing.) Sub-Lieutenant (E)   5.12.18
Geissler, Paul Richard Ewald Marinestabsartz Surgeon-Lieutenant 23. 1.11
Mundi, Walter Obermaschinist Chief Stoker and Chief E.R.A. (1st or 2nd Class) 16. 9.15
Rothe, Bodo Obersteuermann C.P.O. (Navigation 11. 5.17
Wegner, Gerhard Obermaschinenmaat Acting Stoker P.O. and E.R.A. (4th Class) 19. 2.20
Nistelberger, Ludwig Bootsmannsmaat Leading Seaman 18.10.17
Oberhaus, Theodore Maschinenmaat Leading Stoker and E.R.A. (5th Class) 25.11.19
Rodek, Erich Maschinenmaat Leading Stoker and E.R.A. (5th Class)   5. 9.21
Grimm, Bruno Funkmaat Leading Telegraphist 30.7.19
Mang, Josef Funkmaat Leading Telegraphist   8. 8.21
Lenissen, Wili Matrosenobergefreiter Able Seaman 25. 8.23
Brune, Heinz Matrosenobergefreiter Able Seaman 18. 5.23
Keitel, Horst Matrosenobergefreiter Able Seaman 12. 1.23
Niehaus, Wilhelm Matrosenobergefreiter Able Seaman   5.12.22
Lipski, Bruno Matrosenobergefreiter Able Seaman 11.12.23
Seiwert, Willi Matrosenobergefreiter Able Seaman   1. 2.22
Prause, Erich Maschinenobergefreiter Stoker (1st Class)   7. 2.23
Bartzsch, Johannes Maschinenobergefreiter Stoker (1st Class) 25 .4.24
Sawall, Werner Maschinenobergefreiter Stoker (1st Class)   4. 7.23
Meyer, Horst Maschinenobergefreiter Stoker (1st Class) 18. 8.23
Ritter, Hellmut Maschinenobergefreiter Stoker (1st Class)   1. 4.23
Arntzen, Willi Maschinenobergefreiter Stoker (1st Class)   9. 7.22
Altner, Reinhart Maschinenobergefreiter Stoker (1st Class)   1.12.23
Fisch, Robert Funkobergefreiter Telegraphist   5. 6.23
Teichmann, Kurt Funkobergefreiter Telegraphist 27. 4.23
Dorenburg, Helmut Mechanikerobergefreiter Able Seaman (S.T.) 29.10.22
Riess, Hubert Mechanikergefreiter Able Seaman (S.T.) 20.10.24
Otto, Paul Mechanikergefreiter Able Seaman (S.T.) 23. 9.22
Hautkapp, Hans Matrosengefreiter Able Seaman. 30.12.23
Gach, Walter Matrosengefreiter Able Seaman. 25. 1.24
Gaubitz, Heinz Maschinengefreiter Stoker (1st Class) 30. 8.23
Kippes, Hans Maschinengefreiter Stoker (1st Class)   3. 1.25
Erz, Friedrich Maschinengefreiter Stoker (1st Class)   5.11.23
Maier, Otto Maschinengefreiter Stoker (1st Class) 27. 4.24
Nötzel, Hubert Maschinengefreiter Stoker (1st Class)   5. 5.23
Officers . .
Chief and Petty Officers . .
Men . .
          (ii)  Casualties:  
English Equivalent.
Halfpaap (?) Leutnant zur See Junior Sub-Lieutenant.
Weigel, Heinrich Obermachinist Chief Stoker and Chief E.R.A. (1st or 2nd Class).
Lang, Richard Bootsmannsmaat Leading Seaman
Berg, Paul Maschinenmaat Leading Stoker and E.R.A. (5th Class).
Bollinger, Werner Maschinenmaat Leading Stoker and E.R.A. (5th Class).
Schlung, Wilhalm Maschinenmaat Leading Stoker and E.R.A. (5th Class).
Büg, Kurt Maschinenmaat Leading Stoker and E.R.A. (5th Class).
Orthmann, Hans Steuermannsmaat Leading Seaman (Navigation).
Fetzer Mechanikersmaat Leading Torpedoman.
Simmes, Paul Matrosenobergefreiter Able Seaman.
Bohrer, Jacob Matrosenobergefreiter Able Seaman.
Karl, Eduard Matrosenobergefreiter Able Seaman.
Timmermann Maschinenobergefreiter Stoker (1st Class).
Lowski, Hans Maschinengefreiter Stoker (1st Class).
Officers . .
Chief and Petty Officers . .
Men . .
          (iii)  Total Crew:  
Officers . .
Chief and Petty Officers . .
Men . .
  (C50786)     500    11/43  



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