K  r  i  e  g  s  t  a  g  e  b  u  c  h 
  
 
=======================
  
 
Maschine Section
  
 
"U  38"
  
 
Operation from 8.  4. - 27.  4.  1940.
  
     
 
A.) Only minor damage.  Low pressure air pressure reducer failed several times.
   
B.) a)  For the first time, the technical free watch was pooled in Damage control, Electrical and Machinery Groups
  Purpose:  quick response to leaks and failures with enemy action, sealing off of the rooms and relay of orders and information to the control room.  No running back and forth in the boat due to the appropriate division of sleeping places.  The following division has proved itself:
  1/1 Damage control Group foreship, location at the back of the bow room.
  1/1 Electrical Group foreship, location battery automatic switch.
  1/1 Damage control Group aftership, location forward in the stern room.
  0/1 Electrical Group aftership, location E-motor room.
  0/2 Mechanical Group aftership, location diesel engine room.
  E-Obermaschinist in the control room.
  M-Obermaschinist in Diesel room.
  Damage control Group leader is the Unteroffizier of the Damage control Group. 
  If not required in their special groups, they will join the Damage control Croups as necessary.
  Alarm diving is done with one watch.  With attack or listening pursuit the off watch is drawn as above (i.e. not at diving station according to Role Table)
   
  b)  1.  Gyro speed reduction is impractical, the globe lies after a short time.  The gyro was warm (45°C after 3 hours).  A settling time of 5 hours is necessary. That is why it's better to switch off the gyro completely
   
       2.  In order to always have pressure at the High pressure distributor in the aft compartment for ejector cartridges when work is required on the starter air line after the starter air bottles (occurs frequently), the starter line must branch off from the filling line (see Sketch Book Form 15).  The bottles can then also be topped up via the filling connection air bottle 1 (z).  Change required immediately.
   
       3.  As a basic combat circuit for the electrical system, feeding auxiliary switchboards 1 (light), 2 (power), 3 (light and power) directly from the battery has proven to be expedient in order to avoid failures due to the automatic switches falling out.  Even in the event of a stronger effect from depth charges, there were no failures in the lighting circuits, the command element, the position indicators or the motors.  Mount the status box for on-board closures on rubber, since the status lamps were the first to break, and also switch off all lamps (Don't forget to turn them back on before surfacing!).
   
       4.  Oil trace:  After depth charge effects rising of oil was observed from main ballast and reserve fuel oil tank 4 port and 2/3 port.  4 port was pumped to 7 port.  2/3 expressed.  Oil trace remained.  Lubricating oil cooler checked, internal oil bunker oil from 4 and 2/3 expressed, both external fuel oil tanks pumped to 6/7 and the regulating and reserve fuel oil tank. Still a light oil trace. Fuel tank low pressure pump is unusable, because it it too loud for listening pursuit, in addition, correct operation is doubtful despite the pressure gauge.
 
     
     
Click the flag to view the above page from the original German KTB
     
 
- 2 -
 
     
 
       5.  The diving characteristics of the Type IX boat in rough seas and swells are insufficient.  The periscope should be about 2 meters longer, because steering at periscope depth is first tolerable at 15-16 meters.  Additionally the effect of the diving planes is too small.  Double planes or enlarging the surface area is necessary.  Attack at HF - hitherto necessary speed level for sea state - is followed, probably even LF.  At LF and sea state, the hydroplanes are constantly in operation, the starter switch and hydroplane motors are then heard.  As a result it is difficult to break through the screen. In the case of a listening pursuit, you can only get away when the rudder motors are switched to manual. This is impossible at periscope depth.
  Reached diving depth = 52 meters.
   
  c)    See Enclosure.
   
                                                                                                     Chief Engineer
   
                                                                                           signed in draft Dipl.Ing. Müller
                                                                                                        Kptltn.(Ing.)
   
  Comments of the Flottille:
  To B.) a):  The establishment of Damage control Groups resulted inevitably from the strong response to bomb throwing. Numerous daily crash dives must be carried out with one watch to avoid constant confusion. A Damage control Group is particularly necessary in the bow, stern and battery compartments. However, it must be set up with the inclusion of the entire crew.
  To B.) b):  A special order to all boats pointed out the danger of reducing engine speed.
  2:  Change is considered appropriate and will be carried out during repair.
  3:  Direct connection of auxiliary power to the battery is considered necessary. In "U-64" it proved particularly useful after the boat sank.
  4:  Fuel tanks were checked.  By all experience to date, the vacuum pump is considered useless.
  5:  It must be assumed that the demands made here have already been made during construction, since they are of a fundamental nature, because increasing boat size is synonymous with aggravation of the underwater characteristics.
   
                                                                                               The Flottilleningenieur
                                                                                                       
                                                                                                        Kptltn.(Ing.)
   
   
   
   
   
   
   
 
     
     
     
 
- 3 -
 
     
 
Enclosure to Kriegstagebuch Maschine "U  38".
  
     
 
Consumption of:
Sea
Distance
Travel
Fuel
Lub.
Drinking
Potash
Oxygen
Provisions
days
traveled
duration
oil
oil
water
Cartridges
hr min
hr min
nm
nm
m³
Kg
Liters
units
1/atu
kg
1.
134
2
12   -
 -  43
4.478
270
150
-
-
70
2.
153
7
21 36
 2 24
6.210
360
150
-
-
80
3.
174
12
20 20
 3 40
6.390
360
100
-
-
80
4.
316
-
24   -
 -  -
10.360
900
100
-
-
90
5.
194
27
14 36
9 14
6.430
540
100
-
-
90
6.
 92
8
21 03
2 57
5.180
216
100
-
-
90
7.
 65
31
 6 10
16 19
1.280
72
100
13
100
80
8.
 5
49
 1 04
17 58
0.150
18
100
13
150
70
9.
22
51
 3 15
16 13
1.220
54
50
-
-
70
20.
62
23
 4 37
11 19
1.595
54
100
-
-
90
11.
55
34
 6 45
17 15
1.196
45
80
-
-
90
12.
38
42
 3 22
20 38
0.664
18
100
-
-
80
13.
254
4
20 40
 3 20
6.340
126
 70
-
-
90
14.
195
15
18 50
 5 10
5.115
180
 70
-
-
80
15.
240
-
24   -
 -  -
5.800
252
100
-
-
90
16.
182
16
18 16
 5 44
4.620
162
100
-
-
20
17.
229
18
18 13
 5 47
6.100
198
100
-
-
80
18.
97
58
 7 30
16 30
3.250
135
100
-
-
80
19.
130
27
10   -
14  -
3.490
180
100
-
-
45
20.
140
2
11 30
 -  38
4.050
450
 80
-
-
45
Total:
2777 
426 
267 47 
169 49 
83.918 
1950
1950
26
250
1510  
=============================================================================
 
  Battery I total charge:  81020 Ah; total discharge: 80400 Ah  
  Battery II total charge:  81020 Ah; total discharge: 80400 Ah  
  Longest uninterrupted submerged cruise:  20 hours.  
  Lowest during the operation reached compressed air supply:  100 kg/cm²  
  Lowest reached pressure in the hydraulic system:  48kg/cm²  
  Fuel oil inventory on departure: 175,660 m³  
  Fuel oil inventory on arrival:  50,390 m³  
  41,352 m³ were pumped overboard due to oil trace.  
 
To Questionnaire:
To 1.) a): No.
  b): Both diesel LF; Seas about 20° from ahead.
  c): 6°
  d): 18°
  e): The boat is very stiff, therefore always great sea damage on the over deck.  When running before the seas do not run at too low a speed!  Preferable HF.
To 2.)    : No; still too wet.  Lookout in low sea already strongly hindered.  The collar has proven itself.  The attachment of a wind orifice is required for wind protection.  The supplied Plexiglas panes are usable.
To 3.)    : During the 3rd remote patrol (Atlantic-North Sea) about 5 of 40 days.
To 4.)    : No.
To 5.)    : No.
To 6.)    : No.
To 7.)    : HF before the seas.
To 8.)    : 4 times.  Longest duration:  21 hours (CO2 = 3.9%)
To 9.)    : No.  The question of whether steering at depth 20 or 50 meters is more advisable can't be decided yet.  Depth charges received so far detonated when the boat was between 20 and 36 meters at an estimated distance of 200 meters.  Strong concussion.  Feeling of being lifted or springing in the end rooms.