Copy No.          
 
                                                                                 
 
 
 
 
G  e  h  e  i  m  .
  
 
 
 
K  r  i  e  g  s  t  a  g  e  b  u  c  h
  
 
 
 
Section Machine
  
 
Unterseeboote " U 454 " (No. 2)
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Beginning:   25 December 1941
Concluding:   24 January 1942
Patrol:   25 December 1941 Departing Kirkenes
    20 January 1942 Arriving Kirkenes
 
 
 
 
 
     
     
     
     
 
 
 
 
 
 
Click the flag to view the above page from the original German KTB
     
 
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A. Malfunctions, type and correction.
  1) Tear in cylinder head port engine Cylinder I
  2) Chain drive for furl oil feed pump port engine torn.
  3) Leak in cooling water piping starboard engine.
  4) Exhaust valve starboard engine jammed.
  5) Spring exhaust valve starboard I broken.
  6) Water in the attack periscope
  7) Foot steering of the attack periscope is stiff.
  8) Dog in conning tower hatch loose.
  9) Strong leak in high pressure air system.
  10) Failure of the forward diving plane motor.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
 
     
 
 
     
 
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1.) On 29 December the water content of the lubricating oil of the port engine rose to 1.8%.  Measurement showed that compression was too low in cylinder I.  The intake valve of this cylinder seemed bad (unusual noise) and it was removed.  Because there was water on the piston, the engine was placed under cooling water pressure.  As a result, a crack was found in the intake port of the cylinder head.  Replacement of the head did not take place because the spare head was used on the last patrol and in base (Kirkenes) one could not be supplied.  The old head was left on cylinder I.  The fuel oil piping as well as cooling water intake and exhaust to the cylinder head were flanged off, the exhaust gas valve fixed closed.  At the cooling water exit of the cylinder liner a blind disc with valve and rubber hose were mounted. by this movable pipe the cooling water circulation was maintained and the temperature of the cooling water was monitored.  The intake valve was not installed again.  The engine was now again clear for 340 RPM.  To increase the performance, the intake port was sealed at the flange so that the engine with supercharger could be used at 400 RPM and the boat was clear for 15 knots.  In an emergency later 3 x AK even 16.4 knots was reached.
   
2.) On 26 December fuel oil pressure of the port engine dropped.  Investigation while running showed that the chain drive of the fuel oil pump was torn.  The engine was stopped and the chain repaired.  Duration:  1 hour.
   
3.) At GF on 5 January the packing was forced out at the cooling water intake to the starboard engine.  Because propulsion could not be temporarily interrupted, operation was maintained with frequent pumping of the diesel room bilge. With stopped engine the packing was renewed 8 hours later.
   
4.) On 13 January in Cylinder II of the starboard engine the exhaust valve jammed in the closed position.  The valve was replaced.  Duration 1-1/2 hours.  Cause of the malfunction was seizure of the control piston in its upper end position.
   
5.) The spring of the exhaust valve of cylinder I starboard engine broke just below the spring plate.  The valve was replaced, the spring renewed.  Duration 1-1/2 hours.
 
 
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6.) On 5 January the the view through the attack periscope stand was completely blurred.  Because after cleaning the deflecting prisms and drying of the periscope did not correct the malfunction, a thin opaque a thin transparent water layer was found on the glass cover plate.  By careful rinsing of the glass plate with hot air by means of the hair dryer the water on the glass cover plate was indeed eliminated after three hours, but the impurities (reddish dirt flecks) on the glass inside the periscope remained. To eliminate the contamination, the attack periscope must be withdrawn or the head removed. It remained out of service for the duration of the patrol.
  As cause it was determined that the water found its way in through a leak while diving or there is condensation forms when shutting down the warm air system of the shaft. In the latter cast the the contamination is inexplicable.
   
7.) While turning the periscope on 8 January the left foot lever repeatedly hung up so that the periscope continued to turn and could only be stopped by closing off the hydraulic oil line.  The pillar covering was removed and the foot lever controller was checked.  The return spring was broken.  Despite renewal of spring and despite oiling of all moving parts the control foot lever steering was still very sluggish.  The reason for this lies in the strong friction of the Bowden cable. No means is provided for for lubricating or oiling.  Cause of all the trouble is undoubtedly the heavy breakers striking through the conning tower hatch.  The water comes to the fittings of the fixed periscope (even at viewing direction 0°), runs over the collection pan in the conning tower and penetrates into the periscope shaft. Sometimes in bad weather levers and hand wheels must be dried and cleaned often.  Attaching a quick release protection (canvas with a clamp) is proposed.
   
8.) From frequent slamming of the conning tower hatch (due to the Sea State had to proceed with the conning tower hatch closed for a long time), the dogs in the hatch detached.  Contrary to all the other hatches, on the conning tower hatch the dogs are made of brass and are secured only by three bolts, while on all other hatches it is welded and made of iron. The only 4 mm of each bolt's tapping was re-bored and longer bolts were put in. However instead of the current screws, hex screws that can always be re-tightened were used.
 
 
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9.) In the High Pressure air installation there was a leak between the water separator and the filling connection that in the course of the patrol grew so large that pressure only rose slowly when filling the bottle groups.  A blind copper disc was placed between the piping and valve body (filling connection), the "Fill High Pressure-air distributor" valve was shut.  For the duration of the patrol filling was carried out via the distribution line of High Pressure Air Group I.
   
10.) On 13 January 1942 the motor for the forward diving plane failed, the ammeter showed no current consumption.  Investigation showed that the retaining springs in the self starter did not release the switching magnets when operating the control buttons.  Both return springs were reduced in their power; the motor worked properly again.
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
 
     
 
 
     
 
- 4 a -
 
     
 
B. Experience.
  a) Personnel.
    The performance of the engine personnel was satisfactory.  The operational readiness of the engine personnel with the engine malfunctions deserves special mention.
     
  b) Engine and diving installations.
    The frequent breakage of copper oil lines to the main engines is a constant complaint. The lines are usually not mounted vibration-free.  Better holders for these has been provided by Command for the next dry dock overhaul.
     
                                                                            Signed in draft  F r  o  m  m  e