Final Report on U869 Page 2

CONCLUSIONS

Conclusion #1 – The U-869 was sunk at 39º 34’ North Latitude, 73º 02’ West Longitude, while engaged in military operations off the New Jersey coast at some unknown date in either February or March of 1945.

The bowl of course proved that this was a WWII era German U-boat.  The schematic diagram indicated that we had located a type IX C built at the Deschimag yard in Bremen. This limited the possibilities to a submarine with one of the following designations (according to Erich Gröner in German Warships 1815-1945 Volume 2 and confirmed through Vom Original zum Modell: Uboottyp IX C by Fritz Köhl and Axel Niestlé):

U-183 through U-194
U-841 through U-846
U-853 through U-858
U-865 through U-870
U-877 through U-881
and U-889

The schnorkel and the hydrostatic test date indicated that the sinking occurred either in the later part of 1944, or the first half of 1945.  The presence of the “Horenburg” knife (see attached Documents #1 & #2) was problematic in that it took quite a while to develop any historical documentation to place the U-869 in the New York approaches.  At the time, we believed it most likely that Martin Horenburg had been transferred, possibly at the last minute, to replace an injured or ill crewmember on another U-boat (specifically, we suspected for many reasons either the U-857 or U-879).  This could have happened in Norway, at some time in late 1944 or even early 1945, with the records of that transfer being lost in the chaos surrounding the end of the war.  By the time in 1994 when we became aware of the documentation supporting the presence of the U-869 in the New York approaches we felt that the U-Who was most likely the U-869.  We also felt that some sort of corroborating evidence was necessary to rule out the lesser possibility that it was the U-857 or U-879, with Martin Horenburg (or at least his knife) on board.  We were not convinced beyond any doubt that the wreck was that of the U-869 until the recovery of the plastic tag from the Electric Motor Room with the U-boat designation on it.

Conclusion #2 – The U-869 did not receive (or misunderstood) the radio message from BdU (U-boat Headquarters) directing it to change its operational area from the New York approaches to the Gibraltar area.

The U-869 was originally ordered to conduct military operations off the New Jersey coast (BdU KTB December 29, 1944) in the New York approaches. It took the U-869 more than a week longer than expected to break out of the northern approaches into the mid-Atlantic. This delay caused BdU to seriously consider that the U-869 had been lost to Allied Anti-Submarine Warfare forces (BdU KTB December 30, 1944).  When the U-869 finally radioed in their mid-Atlantic position (BdU KTB January 6, 1945), they were re-routed to the Gibraltar area by BdU (BdU KTB January 8, 1945) in order to make the most of their now limited operational time and fuel. This series of messages was the last communication with the U-869.  The U-869 continued on its mission to the New York approaches while BdU fully believed them to be on their way to Gibraltar. The possibility that this was happening was suspected by Allied Intelligence in 1945 solely on the basis of Ultra decrypt information (see attached Documents #3, #4, & #5).

Conclusion #3 –The sinking of the U-869 was the result of a terrific explosion centered on the port side of the Control Room.  There were no surviving members of the crew and no witnesses to the sinking.

As the drawing of the wreck site depicts, the pressure hull is almost non-existent on the port side in the Control Room area. Both of the Control Room bulkheads are separated from the pressure hull, the forward bulkhead with a gap large enough for a diver to easily pass through on the port side. Severe fractures in the pressure hull extend forward on the port side into the officer’s quarters and aft above the Diesel Motor Room. The starboard side of the Control Room has the pressure hull mostly intact, but fractured.  The skin is still on the exterior of the pressure hull in this area, leaving the skin mostly intact along the entire starboard side of the wreck.

Our confidence that there were no survivors or witnesses comes from the fact that we meticulously searched the US Navy Eastern Sea Frontier Diaries and the Allied Anti-Submarine Warfare records.  We examined the records searching for U-boat sightings, missing ships or aircraft, debris sighting, etc.  We searched the record for the entire war and later focused more intensely upon late 1944 and early 1945. Having done this, we could find no entries whatsoever that we could specifically link to the wreck site.

Conclusion #4 – The attack by the USS Fowler and the French Sub Chaser L’Indiscret on February 28, 1945 did not result in the sinking of any German U-boat.

The Allied Assessors assigned credit for the sinking of the U-869 only after post war analysis of the German and Allied records that were made available to them (see attached Document #6).  The reason that the attack was upgraded to a Probable Sinking was due to the fact that the Allied Assessors were trying to account for the loss of the U-869, which they believed to be off the coast of Gibraltar. The Assessors of course did not have the benefits of any of the Ultra Decrypt information, specifically the Tenth Fleet intelligence reports indicating that the U-869 might not have been in the Gibraltar area. If the U-869 was not in that location, then there was no reason for the Assessors to further review and upgrade the original Gibraltar ASW reports. Other than the reported presence of the U-869, both the Allied and German records show no other U-boats in the Gibraltar area during February of 1945.

HYPOTHESIS

Hypothesis #1 – The sinking of the U-869 was the result of a circular run acoustic torpedo that the U-boat fired upon a target that most likely never realized that it was being attacked. The torpedo, unable to locate the intended target, eventually traveled back around striking the U-869.

The detonation most likely occurred on the port side of the Control Room.  The submarine was probably submerged at the time.  The T-5 Acoustic torpedo was most commonly used at single targets to which the submarine was either abeam or aft.  With the target speeding away, it would be unlikely that anyone aboard would notice an explosion that occurred at some distance, possibly miles, astern and underwater.  This explains why there are no ASW or ESF entries relative to this site and also explains the extensive damage we find on the wreck.

Trouble with the T-5 Acoustic Torpedoes was not unknown to the BdU (September 24, 1943 BdU-KTB) and circular run torpedoes are suspected in the sinking of both U-377 and U-972 according to Jak P. Malmann Showell in U-Boats Under the Swastika.

Hypothesis #2 – It has been suggested by some knowledgeable and respected authorities that an action report issued by the SS Harpers Ferry might have some involvement with the U-869.  The authors are not in agreement with this hypothesis for five reasons:

1. The US Naval Gun Crew report is confusing and contradictory (see attached Document #7).  First, visibility is stated as “1000 yards or less”, yet the object fired upon is seen 3200 yards distant and then the fire identified as being “200 to 300 yards” short.  We feel this significantly affects the report credibility.
2. It appears that the patrol plane mentioned in the Gun Crew Report passed close enough to the Harpers Ferry’s port side to be easily identified. The plane, which reportedly dropped the flares, at least 4 flares, never reported to ESF or ASW any submarine sighting. This patrol plane would have certainly been in a more advantageous position to identify any submarine, yet no report was filed by any aircraft or any vessel other than the SS Harpers Ferry. No patrol planes were reported missing and no other incident significant to this location and date could be located
3. The SS Harpers Ferry makes no mention of the incident in its Secret Log (see attached Document #8). The ship’s officers should have noted any sighting of a U-boat in this log, had they made such an observation. In addition, the Official Log (see attached Document #9) of the ship makes no mention of any incident, although we would not necessarily expect any mention of a submarine sighting in this log.
4. The Naval Gun Crew Report places the ship at a location approximately 46 miles south and east from the U-869 wreck site. The co-ordinates given appear to be a DR position calculated for the time of the incident, not the SS Harpers Ferry‘s last recorded position which could have been several hours old. The navigational information is without flaw as best as we can tell. This is to say she arrived in port at the time we would expect from her described course and speed (see attached Documents #7 & #8).  The only way we could place the SS Harpers Ferry over the wreck site is with some significant error in her dead reckoning position, which we cannot find.
5. The severe damage to the submarine and her pressure hull, with the conning tower and schnorkel adjacent to the main body of the wreck, would certainly exclude the possibility that submarine sank at any location other than that where the wreckage is currently located.

It would indeed be convenient to link the SS Harpers Ferry to the U-869 sinking and neatly close the book on the entire case, much like the Allied Assessors attempted in 1945.  Unfortunately, it is our hypothesis that the SS Harpers Ferry was in no way witness to the sinking of the U-869 for the reasons stated above.  It is probable that we will never fully understand the specifics surrounding the sinking of the U-869.

Respectfully Submitted March 1, 1998.