Top Secret.   Copy No. 171
Current Order No. 68 - Issued November 1944
  Maintenance of Firing Rod and Lut angle adjustors in Torpedo Tubes in U-boats Type VII and IX  
  1)  U-boats repeatedly report tube-runners when firing Lut torpedoes.  Cause:  Stiffness of the firing rods and Lut angle adjustors.  
  2)  The following measures should be taken with regard to tubes loaded with Lut torpedoes:  
          a)  The firing springs should be tautened from 267 to 250mm., measured when the firing rod it taught.  
          In addition, the castellated nut should be turned away from the base in the direction of the electro-magnetic firing lever.  It should be observed that the firing spring nut turns back slightly as a result of torsion.  It is therefore necessary to turn the nut slightly further and then turn it back to the correct position.  
          b)  Lut angle adjustors should be engaged and disengaged every day.  For this purpose values on the torpedo firing angle receiver and the Lut setting scale should be adjusted beforehand as for loading.  
          Turning of the torpedoes is not necessary.  During testing, the values on the torpedo firing angle receiver and the Lut setting scale should not ne allowed to alter.  After testing, the angle adjustors should again be engaged.  
          c)  Torpedoes should be completely withdrawn every 8 days, instead of every fortnight as previously, and firing rods should be tested for easiness.  
  1)  Withdraw the torpedo completely.  Empty the discharge cartridge (drain calve, torpedo discharge cartridge remains open).  Insert and fix firing piston (in the piston tube), close to the rear door, flood the tube and open the bow-cap.  Adjust clamping lever to the "On" position, release tube and, holding back the clamping lever, pull the firing rod slowly out and push backwards and forwards several times, lubricating the rod at the same time.  
  2)  Tests are to be carried out on the surface and when submerged to a depth of 50 metres with and without piston tubes.  
  3)  After tests have been carried out, the tube should be replaced and reloaded with torpedo.  
  U-boat  "U-249" 
  Recd.   6th December 1944
  Reg.No.Top Secret134.
  Encl.  ---
                                                                                            Translated by C/W Watson  
                                                                                                                  C/W Robertson  



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