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                                   Current Order No. 69 - Issued March 1945
 
                                     (With reference to the firing of torpedoes by Radar) - O.T. torpedo  
     
     
Torpedoes fired below periscope depth using Radar as a means of sighting 1)  Radar directed torpedoes are fired from a U-boat submerged to a maximum depth of 40 metres.  O.T. fire is forbidden beyond this depth.  
  2)  Instructions regarding the firing of torpedoes without the use of a periscope are contained in Current Order No. 67, and these remain valid.  
     
  3)  The O.T. torpedo is not available at the moment for U-boats Type Rom. 21.  If the results of the current trials are satisfactory, permission will be granted for its use, gradually up to a depth of 50 meters.  
     
  4)  O.T. torpedoes can be used by U-boats with piston tubes (Types VII, IX, IXD, XXIII)  
     
  a)  Air cartridge filling in kilograms Square centimeters necessary for boats with bronze piston tubes at a maximum depth of 35 meters:  
     
 
For surface firing, quantity equals 11 Kg.  
At a depth of 10-12 metres    " 17 Kg.  
  "  "     "     "  12-17     "         " 17 Kg.  
  "  "     "     "  17-22     "         " 22 Kg.  
 
     
  For depths of 22-35 meters, the filling quantity corresponds to the actual depth in meters.  Fluctuations in depth of plus of minus 3 meters are permissible without changing the air cartridge pressure.  Plus or minus 3 degrees beyond the buoyancy limits is allowable, for bow and stern tubes.  Stop pressure in air cartridges must be adjusted to 5 Kg. at 22.  
     
  b)  Boats with steel piston tubes at a maximum depth of 40 metres.  (Air cartridge fillings up to 22 metres in depth as in "a").  For depth of 22-40 metres air cartridge fillings should correspond to the actual depths in metres.  (Otherwise as in "a")  
     
     
     
     
     
     
     
     
     
                                                                                            Translated by C/W Watson  
                                                                                                                  C/W Robertson