-27-
  
     
Top Secret.
249
 Copy No. 4
 
     
 
Current Order No. 45 of February 1945
 
     
 
Procedure against enemy contact buoys.
 
     
          For the guidance of further aircraft or U-boat patrols to the diving positions of clearly sighted U-boats or Schnorchels, enemy aircraft have recently dropped marking buoys.  
     
          Apparently 2 kinds are in use:  
     
  1)  Many listening buoys which give out the noise of U-boat propellers.  Listening range only slight when boat is crawling.  
     
  2)  Wireless D/F buoys, which transmit bearing beams to indicate first diving position to aircraft and searching patrols.  
     
          Procedure:  
     
          After U-boat or Schnorchel has been clearly sighted by enemy aircraft, reckon upon buoys of this kind being dropped.  Sighting of the Schnorchel is only to be expected after an attack has been made, by low-flying aircraft by day or by direct lighting up at night.  Immediately move off from diving position, at high speed, then proceed further at "crawling" speed with a general change of course.  If possible against wind and current.  (Buoys in motion)  
     
          Endeavour to proceed at an unfavorable listening depth.  Wait at least 15 hours before surfacing again (in case of necessity) and wait four hours and until dark before Schnorchelling.  
     
          Conclusions:  
     
          Enemy procedure is primitive, we acknowledge it, however, and practise caution.  
     
 
  U-boat  "U249"
    Recd.     17th Feb. 1945
  Reg No.  Top Secret 199
    Encl.      ----
 
     
         Addendum - Current Order No. 45.  
     
          At the end add:  Note:  When leaving at crawling speed, complete silence must be maintained in the boat, as if the listening buoys are lying close, noises from inside the boat can be intercepted.