Copy No. _46_ of 46.
 
                                                                                                                   S E C R E T
 
 
Op-16-Z
  
 
 
 
NAVY DEPARTMENT
 
 
OFFICE OF THE CHIEF OF NAVAL OPERATIONS
 
 
WASHINGTON
  
 
 
 
FINAL REPORT - G/Serial 34
 
 
 
 
REPORT  ON  THE
 
 
INTERROGATION  OF  SURVIVORS  FROM  U-177
 
 
SUNK  6  FEBRUARY  1944
 
 
 
 
DISTRIBUTION:
  
 
 
 
    BAD
  
 
    BUORD
  
 
    BUSHIPS
  
 
    BUSHIPS (Code 515)
 
 
    BUSHIPS (Code 815)
 
 
    COMINCH (F-21)
 
 
    COMINCH (F-4253)
 
 
    COMINCH (F-45)
  
 
    COMINCH (FX-40)
  
 
    COMINCH (FX-43)
 
 
    COMNAVEU
 
 
    ONI (Ottawa)
 
 
    G-2 (Col. Jones)
 
      Op-16-1 via Op-16-1-F  
      Op-16-1-V  
      Op-16-FA-4  
      Op-16-P  
      Op-16-W  
      Op-20-G  
      Op-23-C  
      SONRD  
      C.O., Naval Unit, Tracy Calif.  
      Lt. J. I. Eiband (CONMAVNAW, CSDIC, AFHQ)  
      Lt. S. R. Hatton (COMNAVNAW, CSDIC, AFHQ)  
      Lt. (jg) R. J. Mullen (4th Fleet)  
      Lt. J. T. Rugh, Jr. (JICA/ME)  
      Lt. Comdr. V. R. Taylor  
      Com 4th Fleet  
 
 
  22 May 1944                                                                                                   S E C R E T  
     
 
 

 

 
 
 
 
 
                                                                                                                           S E C R E T
 
 
 
TABLE OF CONTENTS
 
 
 
 
CHAPTER
I.
   INTRODUCTION
1
 
   
 
II.
   DETAILS OF U-177
3
 
   
 
III.
   TECHNICAL DETAILS AND PROCEDURES
14
 
   
 
IV.
   GUNS AND AMMUNITION IN U-177
19
 
   
 
V.
   MOTORLESS OBSERVATION HELICOPTER ("BACHSTELZE") USED ON 1200-TON U-BOATS
35
 
   
 
VI.
   CREW OF U-177
47
 
   
 
VII
   EARLY HISTORY
54
 
   
 
VIII.
   FIRST PATROL OF U-177
57
 
   
 
IX.
   SECOND PATROL OF U-177
67
 
   
 
X.
   THIRD AND FINAL PATROL OF U-177
75
 
   
 
XI.
   SINKING OF U-177
79
 
   
 
XII.
   OTHER U-BOATS
84
 
   
 
XIII.
   HISTORY AND DETAILS OF U-195
92
 
   
 
XIV.
   GENERAL REMARKS ON U-BOATS
96
 
   
 
XV
   MISCELLANEOUS
100
 
 
 
 
ANNEX CREW LIST OF U-177 AND U.S. EQUIVALENTS OF GERMAN NAVAL RANKS.
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                                          S E C R E T
 
 
 
 
 

 

 
 
 
 
 
                                                                                                                        S E C R E T
 
 
 
ILLUSTRATIONS
  
 
 
 
Plate
Facing Page
   
 
I.
   Complementation and Tank Plan of 1200-ton, type IX D-2 U-boat.
4
  
   
 
II.
   Diesel and Electric Motor Rooms of 1200-ton, type IC D-2 U-boat.
8
  
   
 
III.
   Superstructure of U-177 - Elevation and Plan.
8
  
   
 
IV.
   F.K.W. Long Range Short Wave Transmitter.
18
  
   
 
V.
   F.K.W. Transmitter - Remote Control Panel.
18
  
   
 
VI.
   105-mm. Fuze Setting Key.
22
  
   
 
VII.
   Automatic 37-mm. Gun.
24
  
   
 
VIII.
   Automatic 37-mm. Gun. - Diagram of Automatic Mechanism.
26
  
   
 
IX.
   Automatic 37-mm. Gun - Muzzle and Feed Details.
28
  
   
 
X.
   37-mm. Projectile.
30
  
   
 
XI.
   Helicopter in Operation.
36
  
   
 
XII.
   Helicopter - Diagram
38
  
   
 
XIII.
   Helicopter - Rotor Head and Blades.
40
  
   
 
XIV.
   Operations of U-177 - First Patrol.
66
  
   
 
XV.
   Operations of U-177 - Second Patrol.
74
  
   
 
XVI.
   Anti-Escort Mine.
96
  
 
 
 
 
 
 
 
 
                                                                                                                      S E C R E T
 
 
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
CHAPTER I.  INTRODUCTION
 
 
 
 
        The successful career of U-177, a 1200-ton U-boat ended abruptly in position 10035' S. - 23012" W. at 1029Z on 6 February 1944, 45 seconds after the explosion of depth-charges dropped with devastating accuracy by an Ascension-based P.B.4Y of VB-107.  The history of this U-boat is essentially that of the brilliant exploits of Korvettenkapitän Robert Gysae, of the 1931 Term, under whose command U-177 made two long patrols to the Indian Ocean, in the course of which Gysae was credited with the sinking of fifteen Allied ships, totaling 104,000 tons.  When sunk, U-177 was on her third patrol, under the command of Korvettenkapitän Heinz Buchholz, of the 1929 Term, who relieved Gysae in Bordeaux on 10 October 1943.  She had been at sea 35 days, and was again enroute to the Indian Ocean, where this time she was to carry out her patrol and then proceed to Penang for anticipated Far Eastern operations.
 
 
 
 
        Of the complement of 65 carried on U-177's final patrol, only the second and third watch officers, two petty officers and ten men survived.  The great majority were trapped in the rapidly sinking U-boat;  approximately twenty men escaped the boat, but six of these, including Buchholz, were killed on deck and in the water by subsequent strafing and bombing.  The 14 survivors reached an auxiliary life raft dropped by the attacking aircraft, and were rescued after 56 hours by U.S.S. OMAHA, which landed them in Recife, Brazil.  A preliminary interrogation was conducted in Brazil, and 13 survivors were transferred to an interrogation center in the United States.
 
 
 
 
                                                                         - 1 -                                                 S E C R E T
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
        Buchholz, acting on explicit orders from Commander-in-Chief U-boats, had instructed his crew relative to deportment in the event of capture, with particular recommendations as to the manner in which enemy interrogators could be foiled by false and misleading statements.  While, in consequence, the progress of interrogation was impeded somewhat at the outset, prisoners' security under questioning relaxed swiftly, with salutary results.  No torpedo specialists were among the survivors.
 
 
 
 
        Of particular interest is the extensive use made by U-177 on her second patrol of the helicopter carried aboard.  Chapter V of this report offers a detailed, illustrated account of the construction, operation and maintenance of the helicopter, and of the training of naval personnel in its use.
 
 
 
 
        Other special features of this report are the detailed, illustrated analysis, contained in Chapter IV, of the new type automatic 37-mm. gun recently mounted on German U-boats, and an account of German U-boat operations in the Indian Ocean (Chapters VIII and IX).
 
 
 
 
        Attention is further invited to the diagrammatic drawings of the complementation and superstructure of U-177 (Plate I and Plate III).
  
 
 
 
        U.S. Navy equivalents of German ranks will be found in the Annex.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                         - 2 -                                                 S E C R E T
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
CHAPTER II.  DETAILS OF U-177
 
 
 
 
DISPLACEMENT
  
 
 
 
        1200 tons.
 
 
 
 
TYPE
  
 
 
 
        IX D-2.
 
 
 
 
BUILDING YARD
 
 
 
 
        Deschimag, Bremen.
 
 
 
 
FLOTILLA
  
 
 
 
        12th Flotilla at Bordeaux.
 
 
 
 
FIELD POST NUMBER
 
 
 
 
        M-16669.
 
 
 
 
CALL LETTERS
 
 
 
 
        UHJ.
 
 
 
 
PATRON
  
     
          Hienrich Himler.  
     
  INSIGNIA  
     
          No insignia on Conning Tower.  The informal insignia of U-177, worn as a cap emblem by some of her crew, was a crutch superimposed on a "U".  This insignia commemorated the leg injuries suffered by Kapitänleutnant Gysae in an air raid at Bremen while U-177 was being overhauled preparatory to her first patrol  
     
 
                                                                         - 3 -                                                 S E C R E T
 
 
 

Click this text to view Plate I.  Complementation and Tank Plan of 1200-ton, type IX D-2 U-boat

 
 
 
 
 
S E C R E T
 
 
 
(See Chapter VIII).  One of Gysae's crutches was carried on the bridge as a talisman, and U-177 was known to her crew as "U-KRÜCKE" (U-Crutch).
 
 
 
 
CAMOFLAGE
  
 
 
 
        None.  Dark gray paint over-all.
  
 
 
 
DIMENSIONS
  
 
 
 
        Length over-all - 87 meters.
 
 
        Beam               - 6 meters.
  
 
        Draft, fully loaded - 5.20 meters.
 
 
        Draft, unloaded - 4.50 meters.
 
 
        Pressure Hull (Diameter) - 5.60 meters.
 
 
        Pressure Hull plating, thickness of:  25 mm.
 
 
 
 
COMPARTMENTATION
  
 
 
 
        (See Plate I).
 
 
 
 
PRESSURE PROOF BULKHEADS
 
 
 
 
        Four, as follows:  (See Plate I).
 
 
 
 
        1.  Between forward torpedo room and petty officers' quarters
 
 
        2.  Between officers' quarters and Control Room.
 
          3.  Between Control Room and Diesel Engine Room.  
          4.  Between Electric Motor Room and after Torpedo Room.  
     
  HATCHES    Five as follows:  (See Plate I).  
     
          1.  Forward Torpedo Room.  
          2.  Galley.  
 
 
 
                                                                         - 4 -                                                 S E C R E T
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
        3.  Control Room.
 
 
        4.  Diesel Engine Room.
 
 
        5.  After Torpedo Room.
 
 
 
 
PERISCOPES
  
 
 
 
        (a)  On first and second patrols, normal equipment (one observation periscope, power turned, with fixed eyepiece; one hand-operated attack periscope).
 
 
        (b)  On final patrol, two hand-operated attack periscopes with elongation of 2 meters, permitting periscope depth procedure at 17 meters.  The power turned observation periscope was removed and the two new periscopes were fitted in U-177 at Bordeaux in November or December 1943.
 
 
 
 
TANKS
  
 
 
 
        (See Plate I.)
  
 
 
 
DIVING
  
 
 
 
        Depth Gauges
 
 
                (a)  "Papenberg" gauge in Control Room, graduated to 25 meters - for operation at periscope depth.
 
 
                (b)  Two pressure-spring type gauges graduated to 200 meters.
 
 
 
 
        Tested Depth
 
 
                90 meters.
 
 
 
 
 
 
                                                                         -5 -                                                 S E C R E T
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
        Periscope Depth
 
 
                On first and second patrols - 15 meters.
  
 
                On final patrol                    - 17 meters.
 
 
 
 
        Crash-Diving Time
 
 
                38 seconds to periscope depth at flank speed.
 
 
 
 
        Maximum Depth Attained
 
 
                140 meters (in deep dive tests).
 
 
 
 
BRIDGE ARMOR
 
 
 
 
        16-mm. armor plate fitted around bridge fairing.
 
 
        2 extra armor plates were riveted to the sides of the Conning Tower for delivery in Penang.
 
 
 
 
AIR RAID SHELTER ON BRIDGE
 
 
 
 
        Not fitted.
 
 
 
 
GUN PLATFORMS
 
 
 
 
        Two.  (See Plate III.)
 
 
 
 
ARMAMENT
  
 
 
          Guns and Ammunition  
                  For detailed information on this subject see Chapter IV.  
     
          Torpedo Tubes  
                  Four bow, two stern.  
     
          Torpedoes Carried  
                  (1)  On first patrol - 24.  
                  (2)  On second patrol - 24.  
 
 
 
                                                                         - 6 -                                                 S E C R E T
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
                (3)  On last patrol - 26 or 27 (including four T-5a)  Distribution of the 24 torpedoes on U-177's second patrol was given as follows:
 
 
 
 
                Bow tubes - 4.
 
 
                Below plates, forward - 4.
 
 
                On plates, forward - 2 (1 port, 1 starboard).
 
 
                Stern tubes - 2.
 
 
                On plates, aft - 2 (1 port, 1 starboard).
 
 
                Upper deck containers - 10.
 
 
                (Corresponding distribution of torpedoes is believed to have obtained on the first patrol.)
 
 
 
 
                The 10 torpedoes in the upper deck containers were air-driven; the 14 in the boat were electrics.
 
 
 
 
                No F.A.T.'s of T-5's were carried on the first two patrols.
 
 
 
 
                Distribution of the 26 or 27 torpedoes carried on the last patrol was similar to that on the second patrol, except that 12 torpedoes were carried in the upper deck containers, and three torpedoes were on the floor plates aft.  16 or 17 torpedoes were T-1's and T-3.  Six or seven were F.A.T.-1's and F.A.T.-2's.  The distribution of the four T-5's carried was variously said to be:
 
 
 
 
                (a)  One in a stern tube.
 
 
                      One in a forward tube (Tube No. 1 or No. 3).
 
 
 
 
                                                                         - 7 -                                                 S E C R E T
 
 
 

Click this text to view Plate II.  Diesel and Electric Motor Rooms of 1200-ton, type IC D-2 U-boat

Click this text to view Plate III.  Superstructure of U-177 - Elevation and Plan

 
 
 
 
 
S E C R E T
 
 
 
                      Two on floor plates aft (1 port, 1 starboard).
 
     
 
                (b)  Two in stern tubes.
 
 
                       None in forward tubes.
 
 
                       Two on floor plates aft.
 
     
 
                (c)  Two in forward tubes.
 
 
                       Two in after tubes.
 
 
                       None stowed.
 
     
 
                Pi-4 pistol was used with the T-5 torpedo.
 
 
 
 
MINES
  
 
 
 
        Never carried aboard U-177.
 
 
 
 
HELICOPTER
  
 
 
 
        (For detailed information on this subject see Chapter V.)
 
 
 
 
SCUTTLING CHARGES
 
 
 
 
        Carried but never installed.
 
 
 
 
WELDING EQUIPMENT
 
 
 
 
        Underwater welding equipment carried.
 
 
 
  DEPTH CHARGE PLOTTER
 
 
 
          Not fitted.  
     
  S.B.T. (SUBMARINE BUBBLE TARGET)  
     
          Fitted in after head (See Plate II.)  
          Two boxes of charges carried.  
     
  PROPULSION  
     
          (For details see Chapter III and Plate II.)  
     
 
                                                                         - 8 -                                                 S E C R E T
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
        Main Diesels
 
 
                2 M.A.N. 9 cylinder, 220 H.P. each with supercharging; 1500 H.P. without supercharging.
 
 
 
 
        Estimated speeds and R.P.M. (on both Diesels):
  
 
 
 
Full Speed - 17 knots, 430 R.P.M.
4/5 Speed - 15 knots, 405 R.P.M.
3/4 Speed - 13 knots, 350 R.P.M.
Half Speed - 11 knots, 300 R.P.M.
Slow -   9 knots, 230 R.P.M.
Dead Slow -   7 knots, 185 R.P.M.
 
 
 
 
        Auxiliary Diesels
 
 
                Two M.W.M. (Motoren Werke Mannheim) 6 cylinder, 500 H.P.
 
 
 
 
        Super Changers
 
 
                Büchi type fitted for main Diesels.
 
 
 
 
        Fuel Oil Capacity
 
 
                510 tons on final patrol.
 
 
       
 
 
        Electric Motors/Generators
 
 
                Two Siemens - Schuckert, 600 H.P. each.
 
 
 
 
        Auxiliary Generators
 
 
                Two Siemens - Schuckert.
 
 
 
 
        Switchboards
 
 
                Siemens - Schuckert.
 
     
  BATTERIES  
     
          Hafag, two banks of 52 cells each.  
 
 
 
                                                                         - 9 -                                                 S E C R E T
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
COMPRESSORS
  
 
 
 
        Two Junkers compressors and 1 electric compressor.
 
 
 
 
COMPRESSED AIR SUPPLY
 
 
 
 
        Eight groups of 3 bottles each.
 
 
 
 
PUMPS
  
 
 
 
        (See Plate II.)
 
     
 
        (a)  Main bilge pump.
 
 
        (b)  Auxiliary bilge and trim pump (Control Room),
 
 
        (c)  Auxiliary bilge pump (forward Torpedo Room).
 
 
        (d)  Auxiliary bilge pump (after Torpedo Room).
  
 
        (e)  Auxiliary engine cooling water pump.
 
 
 
 
FRESH WATER STILLS
 
 
 
 
        (See Plate II.)
  
     
 
        Two - capacity of 32 liters each per day.
 
 
 
 
GERMAN ASDIC
 
 
 
 
        Not fitted.
 
 
 
  RADAR  
     
          Not fitted.  Prior to her final patrol, U-177 was equipped with the housing for radar antenna in conjunction with the extensive alterations made in her bridge structure.  
     
  RADAR DECOY BALLOONS  
     
          two boxes carried on final patrol.  None was used operationally, but one balloon was released experimentally  
     
 
                                                                         - 10 -                                                S E C R E T
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
off La Pallice shortly after departure.
 
 
 
 
G.S.R. (GERMAN SEARCH RECEIVER)
 
 
 
 
        Wanz G-2, 2 "Naxos" sets with 2 aerials, and a "Borkum" set were fitted for the last patrol.  (For details of these sets see G/Serial 30, U-231, pages 8, 13.)  On her first and second patrols, U-177 carried a metox R600 receiver with cross-type aerial.
 
 
        The fixed dipole aerial was mounted on the periscope support in the center of the bridge rather than in the usual position on the bridge fairing.
 
 
 
 
D/F GEAR (DIRECTION FINDER)
 
 
 
 
        Standard Lorenz M/F D/F set.
 
 
 
 
COMMUNICATIONS EQUIPMENT
  
 
 
 
        Transmitters
  
 
                (1)  Telefunken 200 watt H/F Transmitter, 20 to 80 meter wavelengths.
  
 
                (2)  Telefunken 200 watt F.K.W. (Fernverkehrskurzwellensender) H/F Transmitter, 13 to 100 meter wavelengths, fitted with separate remote control panel.  (See Chapter III, Plate IV and Plate V.)
 
 
                (3)  Telefunken 150 watt L/F Transmitter, 250-1500 meter wavelengths.
 
 
                (4)  Lorenz 40 watt emergency transmitter.
 
 
 
 
        Receivers
 
 
                (1)  "Main" short wave receiver (Telefunken).
 
 
 
 
                                                                         - 11 -                                                S E C R E T
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
                (2)  Telefunken all-wave receiver.
 
 
                (3)  "Elak" 10/12 broadcast receiver.
 
 
 
 
        U.T. (Underwater Telegraph)
 
 
                Fitted.
 
 
 
 
        U.K. Gear  (Ultra Short Wave)
 
 
               Fitted.  Lorenz manufacture.  (See Chapter III.)
 
 
 
 
        Broadcast Amplifier (40 watt)
 
 
                Fitted.
 
 
 
 
ROTARY CONVERTERS
 
 
 
 
        One 6 KVA for main transmitter and general radio purposes.
 
 
        One 1 KVA for hydrophones and U.T.
 
 
        One 0.3 KVA for echo-sounder and gyros.
 
 
        The 0.3 and 1 KVA converters could be used interchangeably.
 
 
 
 
HTDROPHONES
  
 
 
 
        (a)  "Atlas" G.H.G. multi-unit hydrophones fitted.
 
 
        (b)  K.D.B. removed after second patrol.
 
 
 
 
ECHO SOUNDER
 
 
 
 
        "Elaklot" fitted.
  
     
  GYROS  
     
          Anschütz.  Master in Control Room and 7 repeaters located as follows:  
          (1)  Bridge.  
          (2)  Conning Tower.  
          (3)  Control Room.  
     
 
                                                                         - 12 -                                                S E C R E T
 
 
 

 

 
 
 
 
 
S E C R E T
 
 
 
        (4)  Diesel Engine Room.
 
 
        (5)  Electric Motor Room.
 
 
        (6)  Radio Room.
 
 
        (7)  Sound Room.
  
 
        A repeater connection was also fitted in the after Torpedo Room.
 
 
 
 
AIR PURIFICATION
 
 
 
 
        (a)  "Klima-anlage" air conditioning system, capable of reducing humidity by 1.5 per cent per hour.  Non-cooling.
 
 
        (b)  "Kalipatronen" potash cartridges carried.
 
 
 
 
LIFE-SAVING AND ESCAPE GEAR
 
 
 
 
        One inflatable rubber dinghy carried.  Standard life jackets and escape lungs carried.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
           &nbs