QUESTIONS FOR P/W EX - U-761
 
     
         Tactical A/S problems in the Mediterranean Approaches are a legion and air and surface intelligence officers have bombarded us with questions.  In addition, the sinking of U-761 was the first in which the new MAD device has been successfully used and the Naval air authorities with ComMorSeaFron are very anxious for all details of the sinking and the and the period immediately before.  The following questions have been suggested:  
     
  SINKING  
     
          (1)  Detailed account of 24 hours prior to sinking.  
          (2)  Exact details of sinking, with special regard to sequence of events and damage.  

   
PASSAGE OF BAY OF BISCAY
 
          (1)  Speed of advance.  
          (2)  When and how long surfaced.  
          (3)  Course.  
          (4)  Use of fishing vessels as camouflage or Radar protection.  
          (5)  What communication with Control?  
     
  MEDITERRANEAN APPROACHES  
     
          (1)  General policy and tactics in Approaches.  
          (2)  Do U-boats wait around or make straight for Mediterranean?  
          (3)  Do U-boats bottom in Approaches?  Where?  
          (4)  What is course after rounding Spanish Coast and heading for Mediterranean?  Is course Cape St. Vincent - Cape Spartel?  
          (5)  Any communication from Control on Allied patrols or any special  
     
     

 

     
     
  MEDITERRANEAN APPROACHES (CONTINUED)  
     
          briefing before leaving base?  
     
  PASSAGE OF GIBRALTAR STRAITS  
     
          (1)  Any details on above.  
          (2)  After passage do U-boats -  
                  (a)  Hug Spanish Coast?  

                (b)  Hug North African Coast.  
                (c)  Stay in middle.
 
  GENERAL  
     
          (1)  Do U-boats listen in on 10 cm. Radar?  
          (2)  What explains explosions in U-boat batteries?  
          (3)  What causes "unexplained explosions" in U-boats after D/Cing?  
          (4)  Are T-5's always set to "Curly."?  
     
     
     
     
     
     
     
     
     
     

 

     
     
  SECRET                                                                                                          23 March 1944.  
     
 
QUESTIONS SUGGESTED FOR USE IN THE
 
 
INTERROGATION OF U-761
 
     
  1.  Knowledge of Impending Attack.  
     
          (a)  What was first evidence of presence of enemy?  
          (b)  Where any peculiar sounds heard by the sound operator?  

               (This refers to the dropping of float lights by the aircraft which would produce audible splashes as they hit the water)  
        (c)  Could the aircraft motors be heard at any time before the attack took place?
        (d)  Were the aircraft radio transmissions picked up?
          (e)  Were any of the crew conscious of any unusual tactics on our part preceding the actual attack?  
     
  2.  First Attack.  (The action referred to is that which took place prior to the first temporary surfacing of the U/boat)  
     
          (a)  How many explosions were heard?  
          (b)  Was there an appreciable time interval between the first explosion and succeeding explosions?  
          (c)  Was the first explosion as loud as the usual depth charge explosion?  
          (d)  Where did the various explosions occur?  
          (e)  How damaging was the first explosion?  The remaining explosions?  
     
  3.  U-Boat Evasive Action.  
     
          (a)  What evasive tactics were pursued when the enemy (our destroyers or planes) was detected?  
          (b)  How deep was the U/Boat at the time of the first attack?  
          (c)  What were the course and speed of the U/Boat at this time?  
     
  4.  Procedure for Passing Through the Straits.  
     
          (a)  What was the approach to the Straits?  
          (b)  Were there any incidents delaying the start of the passage?  
          (c)  At what time and in what location was the passage started?  
          (d)  What was the proposed course, speed and depth to be used in making the passage?  
          (e)  Were instructions for making the passage issued by headquarters?  
          (f)  Did the crew have any advance warning of special antisubmarine measures they were likely to encounter in passing through the Straits?  
     
     

 

     
     
  SECRET                                                                                                          23 March 1944.  
     
  5.  Magnetic treatment of U/Boats.  
     
          (a)  Describe as closely as possible what magnetic treatment was given the U/Boat while in dock?  
          (b)  How was the success of the treatment determined?  
          (c)  What was the resultant magnetic field of the U/Boat?  (Note:  This de-magnitization is described in German publications as Einmagnetisierungsbehandling or Magnetische Eigen schurtz)  
     
     

   
 
 
     
     
     
     
     
     
     
     
     
     
     
     
     
 
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