Copy No. . . . . . . . .
     
 
- Official Document / Handle only by Officer-
 
     
 
E  n  c  l  o  s  u  r  e
  
 
to Operations Order Mediterranean No. 12.
  
     
 
          Experiences in the months of November - December, 1943
  of the boat "U-230" which passed through the Gibraltar Strait
  Kommandant Kapitänleutnant  S  i  e  g  m  a  n  n  .
   
1.) Route of advance:
 
Via the squares BF 5572, BF 8823, BF 8734, BF 8478,
  BF 7923, BF 7894, BF 7889, CG 2568,
  CG 2893, CG 5238, CG 5551, CG 5582,
  CG 5893, CG 8239, CG 8348, CG 9147,
  CG 9183, CG 9514, CG 9584, CG 9586,
  CG 9595, CG 9672, CG 9682, CG 9639.
   
2.) Excerpt of the K.T.B. of the boat.
 
03.12.43    
20.00 CG 9172  
23.08   Surfaced.  Boat ventilated.  Charging transit.  My next goal is the Spanish destroyer training area reported Officer Only Radio Message 1926/25/97  limited by naval squares CG 9433, 36, 9512 and 9515.  If possible, I want to reach it with a full battery and filled air supply. I believe that from there [one is] within range of "continuous locating".  I want to put the boat on the bottom there and proceed from that point in short jumps to about CG 9581.  For the breakthrough itself, I have planned for Sunday, 5 December.  From naval square CG 9581 I intend to start out the morning submerged and pass through the Strait during the day.
     
04.12.43 South coast of Portugal and Spain  
00.00 CG 9147  
00.02   Dived.
03.08   Surfaced.  Charging transit.
04.00 CG 9183  
  SE 3, Sea 3, partial overcast, 1015 mb, 17°C  
06.45   Dived.
08.00 CG 9512  
08.30   Reached the Spanish training area.  Battery is full.  Also air banks.  No one suspects me here.
08.30 CG 9514 Put the boat on the bottom.  5 tons negative buoyancy.  depth 75 meters.  Made final preparations
                                                                    for
 
     
 
 
Click the flag to view the above page from the original German KTB
     
 
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    for long submerged cruise.
12.00 CG 9514 Day's run: Surfaced 53.4 nm,
                    Submerged 30.9 nm = 84.3 nm.
16.00 CG 9514  
20.00 CG 9514  
20.15   Boat raised from the bottom.  Proceeded submerged.
23.05   Surfaced.  Ventilated and charged.
23.53   Dived.  Proceeded submerged.
     
05.12.43 West of the Strait of Gibraltar
00.00 CG 9541  
04.00 CG 9548 Surfaced.
  S 3, Sea 3, cloudy, 8/10, 1005 mb, 15°C  
05.50 CG 9584 Battery and air are full.  The undetected approach is successful.
05.56   Dived.  Ship's position is exact (3 lighthouses) Cape Spartel distinguished.  Submerged breakthrough of the Strait of Gibraltar begun.  The motors 90 RPM (silent speed of the boat = 2 knots).  Course 120°.  Depth = A -30 meters.  I want to approach Cape Espartel up to the 200-meter line and then parallel to this through the Strait.
08.00 CG 9585 Several propeller sounds, occasionally two steamer propellers in a northwesterly direction are made out.  Shifting quickly ahead in the direction of the Mediterranean.  Do not feel like attacking, am not compelled.
10.00 CG 9586 Course change to 65°.  Since 07.05 hours in the sound gear many annoying sounds (Racket, squeaking, crackling), that arise neither from the vessels or from the boat.  Listener suspects hog fish.
12.00 CG 9594 Day's run: Surfaced 31.3 nm,
                    Submerged 31.3 nm = 62.6 nm.
13.00   Course 80°.
15.50   At periscope depth for bearings.  Position by careful bearings about abeam Tarifa.  However, no bearings are possible because of the heavy thunderstorms.  I recognize only quite vague outlines from the European shoreline.  The African shore is clearer. I see that I am positioned abeam of a city, a mountain with tower taken at first thought to be Malabata, is identified as the city of Tangier. Disappointed at first, believed to have been in a counter current. Decided to look again shortly.
                                                                     /16.00
 
     
 
 
 
     
 
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16.00 CG 9672  
16.30   At periscope depth:  A happy surprise. It is clear. The city thought to be Tangier city turns out to be Ceuta, Monte Hacho is unmistakable. Gibraltar is to port, the massif is already well out the eastern side. The concrete areas (water works) are unmistakable.  The line Cauta - Gibraltar was therefore passed at 16.00 hours.
16.35   Exact ship's position:  Monte Hacho (Ceuta).  186°T, 4 nm away  Boat is in the Mediterranean.  Breakthrough completed.  Off Gibraltar a small vessel.  Only masts and smokestack are seen, course west, possibly a patrol boat.  No sound bearings, was completely covered by unexplained annoying sounds (like chopping wood, motorcycle).  The boat has covered 45 nm in 10 hours 38 minutes.   That means 4.2 knots over the ground at silent running RPM.  On average the current was 2.2 knots to the east.  Intend to continue transit submerged via CG 9681, 9659, 9639 under the protection of land.
19.30   Two patrol boat sounds and locating sounds (far off) from the direction of Gibraltar.  Volume varies greatly.  I do not feel I am detected.
20.00 CG 1682  
     
06.12.43 Western Mediterranean
00.00 CG 9659  
04.00 CG 9659  
07.01 CG 9639 Surfaced.
07.19   Dived.
08.00 CG 9639  
11.30   At periscope depth, boat positioned in the bay off Malaga.
   
 
Summary and collected experiences for the successful breakthrough of the Gibraltar Straits.
        In addition to the fortunes of war necessary for this task which enabled me to advance unnoticed to the western exit of the Strait to naval square CG 9584, the following points may have contributed to the success.
1) Secrecy:
  An 15 November 1943 the departure was delayed and the Kommandant was ordered to Toulon for instruction.  In the base of the 9. U-Flottilla only a small circle was informed of the the objective of the voyage and the task derived there from. The task was first announced to the crew and their officers at sea.
 
     
 
 
 
     
 
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2) The route for the advance was elected along the Spanish and Portuguese coast in the belief that there the air surveillance was lower than farther removed from the coast (Gibraltar - England convoy route).
3) I found it pleasant that I did not depart simultaneously with several boats with the same task from the western bases, so that I was not particularly tempted to hurry to be the first.
4) Although I departed from Brest just under 5 days before new moon, I did not hurry, only charging transit on the surface, submerged at economical consumption, one E-motor 90 RPM.
5) I was determined from the outset to carry out the break through submerged as far as possible. Therefore, the new moon phase and the day's run were not of crucial importance, according to the observations made by me concerning patrol of the Strait by day, I saw only one steamer. Later, on passing close Gibraltar - Ceuta, possibly two were heard in the direction of Gibraltar, a successful outcome by day seems promising to me.
6) It seems favorable to me to leave the time around the new moon free, because in my opinion the enemy expects U-boats mainly at this time.
7) The low traffic in the Strait at the moment of my breakthrough - no convoys in East-West or West-East direction - also facilitated my task. It was also advantageous to me that the breakthrough was on a Sunday.
8) I have, from square CG 9584 - CG 9672 along the 200-meter line at depth A -30 meters, made a speed of 4.2 knots with both side 90 RPM, that is to say there was an easterly current of 2.2 knots.
9) I am convinced that submerged locating or listening is ruled out in the Strait. I can confirm the previous experience of other boats of the peculiar listening conditions.
10) The following measures were taken in preparation:
  On the surface along the 100-meter line, submerged along the 200-meter line. I was determined in the discovered Gibraltar maneuvering area east of Cape Vincent if necessary to proceed via shallow water in the dark night hours . Additionally I had emergency breathing apparatus for every man on board.
  For the breakthrough I was prepared for 50 hours submerged transit. The galley was not in service, cold food had been prepared beforehand and was served. This has proven to be a powerful consumer of oxygen. On surfacing for ventilation, which was possible after 25 hours, the air was very good, The emergency gear was put in operations after 10 hours submerged transit. Capacity for a total of 37 hours submerged transit was 6400 Ampere hours per battery
11.) Transit depth for all submerged transit was A -30 meters.