U 864 – “Operation Caesar”

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After its construction at Deschimag AG Weser at Bremen, the Kriegsmarine Type IX D2 U-boat U 864 (Displacement 1,804 t submerged, length 87.6 m, beam 7.5 m, speed at surface 19.2 kn and 6.9 kn submerged, range up to 23,700 nm at 10 kts, 4 bow and 2 stern torpedo tubes, 24 torpedoes on board, also mines, 3 inch gun, complement between 55 and 63 men) was commissioned on 09 December 1943. Its Commanding Officer was Korvettenkapitän (= Commander) Ralf-Reimar Wolfram, who had a first tour as Commanding Officer on board U 108, to execute three successful combat patrols. Following extensive basic and combat training in the Baltic Sea, U 864 left Kiel on 05 December 1944 to be assigned as front U-boat for long range combat missions.

Its first combat mission was at the same time the task to transport essential war material as well as components and blueprints of German jet aircraft Me 163 and Me 262 to Japan. For that purpose there were even German aircraft engineers among the passengers on board. Part of the essential war goods were, inter alia, 1,857 metal cylinders containing some 65 t of mercury. The mission was given the codeword “Operation Caesar”.

Commissioning of U 864 on 09/12/1943
Commissioning of U 864 on 09/12/1943

These transport missions executed by U-boats for strategic goods, important blueprints and components of aircraft, missiles and other weapon developments, as well as personal between the Axis Powers Germany and Japan occurred within the framework of the agreement of 1942 on military cooperation by both countries, whose implementation has subsequently seen several voyages by German and Japanese U-boats between Europe, South East Asia and Japan. We have reported about those in our series “Myths” by telling the story of U 234, which was another of such voyage, although it started a few months after U 864.

After U 864 spent the turn of the year 1944 to 1945 in Norway, it left its base at Bergen, Norway on 07 February 1945 with an unusual large crew of 70 men plus 3 guests. However, soon after its departure it suffered from a severe damage to one of the main engines, causing the Commanding Officer to abandon the voyage and return to base for repairs. Unfortunately, the broken engine caused very loud noises, which meant a considerable disadvantage for U 864 in terms of being detectable much easier than under normal conditions.

Korvettenkapitän Ralf-Reimar Wolfram
Korvettenkapitän (Commander) Ralf-Reimar Wolfram

The mission of U 864 transporting essential goods, documents and specialists to Japan had become known to British intelligence not only through its much advanced ability within the last years of Anti-Submarine Warfare to decipher German U-boat message traffic, but also through other sources. Consequently, a Royal Naval submarine could be tasked directly against U 864 before the Norwegian coast off Bergen. HMS Venturer under the command of Lieutenant James H. Launders was given the task, which was a submarine with many successes so far, even against German U-boats.

The Royal Navy´s submarine HMS Venturer (P-86) was part of the series of smaller coastal “V”- Type submarines (Single hull submarine, displacement 740 t, length 62.3 m, beam 4.9 m, speed 11 kn at surface and 10 kn submerged, 4 bow torpedo tubes, a 3 inch gun and a complement of 37). It was commissioned on 19 August 1943 and executed two combat patrols under Lieutenant James H. Launders, sinking 3 vessels. Most remarkable, however, the sinking of the surfaced U 711 on 11 November 1944 some 7 nm east off Andenes in Norway.

HMS Venturer managed to detect and to pursue U 864. During the following moments an operation not seen so far developed, when one submarine hunted another submarine, with both being submerged. Today, Anti Submarine Warfare is a rather standard capability of any submarine. Lieutenant Launders demonstrated a remarkable operational skill and highly developed tactical abilities while chasing the German U-boat – and he had enough luck on his side. Launching fan-like four torpedoes simultaneously from a distance of about 2,000 m he succeeded hitting U 864 with one of the four torpedoes, which led to total destruction of the German U-boat. Any defensive action by U 864 after it detected the approaching torpedoes have not been established yet by research. None of the 73 men on board U 864 did survive the sinking.

HMS Venturer - versenkte unter seinen Kommandanten, Lieutenant James H. Launders U 771 und U 86
HMS Venturer – was credited with the sinking of U 771 and U 86 under it´s CO, Lieutenant James H. Launders

In March 2003 the wreckage of U 864, broken into two parts, was discovered some 150 m deep in the waters of the Bergen approaches, off the Norwegian island of Fedje. Since, it has caused much concerns. Besides the questions as to the safety of the weapons still on board, and particularly the contents of the batteries, the main worries are about the cargo of mercury. It is feared that the metal cylinders with the mercury inside might corrode sooner or later, releasing their toxic contents to the environment of the sea, to cause damage whose effects cannot be estimated to full extent yet.

One sees hefty coverage by the media, above all, of course, in Norway, often marked by much specu-lation and wild scenarios, as usual given the situation. Following an initial plan in 2007 to simply cover the wreckage by a sarcophagus made from concrete further examinations led the Norwegian govern-ment to decide in early 2009 to attempt after all a salvage operation of the U-boat. Costs are estimated to amount to about 45 million Euros. However, further examinations of the rather complicated salvage maneuver were executed, inter alia, by the Dutch salvage company of Smit (did recently recover the Russian Kursk) and the competing Norwegian company of “Eide Marine Services”. Lately, on 05 March 2010, the newspaper “Bergens Tiderne” reported of a salvage attempt in 2012.

On 18 October 2011, German TV Channel SAT 1 screened at primetime the German TV drama “Am Ende Hoffnung” (= “Hope at the End”), which covered the story of a young women in Germany at the end of 1944, who had to split her feelings between two men: A medical doctor of Anglo-German orign, who worked in a German military hospital but was a British secret agent at the same time, and a German U-boat officer, whom she had to spy about with regard to U 864. The wholly invented story used the factual events around the last voyage of U 864, to create a movie under considerable efforts, most remarkable many scenes shot around and within an U-boat, which was to represent U 864.

Noteworthy about this last voyage of U 864 are a few things:

  1. The alliance between Germany and Japan lived up to the very last months of the war.
  2. A direct communication between both countries was to be managed through U-boats only.
  3. Mutual transports by U-boats, from 1943 onwards also by seized Italian U-boats, were used to ship war-essential personal and material, as well as the latest developments in arms design in form of blueprints and components.
  4. The Type IX U-boats with their great range have demonstrated their capability to overcome the enormous distances between Europe-South East Asia at several occasions.
  5. Another time, the rather inferior operational situation of German U-boats became obvious vis-à-vis the British intelligence almost perfect at that time, which knew extensively about the mission of U 864.
  6. The success of HMS Venturer over U 864 was, by all means, a brilliant tactical achievement, and it was the only sinking of a German U-boat in WW II by another submarine submerged as well.
  7. Certainly, U 864 had extreme bad luck with its technical equipment, whereas HMS Venturer had the necessary luck in detecting and hitting on its side.
  8. Wreckages such as U 864 may constitute an immediate danger to the environment, even 60 years after it was sunk.


  • www.wikipedia.de
  • www.U-boat.net
  • Kristian Büsch “Tod aus der Tiefe” (=” Death from the Deep”) of. 20 February 2007 under www.nachrichten.freenet.de/wissenschaft/geschichte
  • ZDF-Expedition, 11 February 2007, including Videos, Spiegel online of 09 February 2007: “Volltreffer auf U-864: Das erste Unterwasser-Duell der Geschichte” (= “Full hit on U-864 – the first underwater dueling in history”).