Figure 1.--.

The mission of the U-234 continues to be one of the unresolved mysteries of Worlsd War II. The U-234 was a very large mine-laying U-boat--the XB type mine layer. Because of its size it was converted as a Japan transporter, thus becoming an undersea freighter to carry a much larger cargo than a standard U-boat. Even so it held only a fraction of the cargo of a surface merchant vessel. The U-234 was dispacted to Japan with a cargo of German high-tech equipment. The U-234 departed Kiel headed for Kristiansand, Norway (March 25, 1945). The ship departed Norway for Japan (April 16, 1945). The cargo included drawings, a Me-262 jet fighter in crates, air defense radars and jet engine equipment as well as two German experts on various weapons technologies and two Japanese officers. What made the U-234 especially interesting was 80 gold-lined lead cylinders containing 560 kilograms of uranium oxide marked "For the Japanese Army". There is very limited cargo space even aboard this cargo U-boat. Thus only items of the highest priority would have been loaded. Cpt. Fehler received cease-fire orders (May 4). He decided to surrender to the Americans. The Captain claimed to know nothing about the uranium. The only pupose for the uranium oxide given the state of Japanese nuclear research would have been a dirty bomb. Also aboard were two Japanese officer--Air Force Colonel Genzo Shosi, an aeronautical engineer, and Navy Captain Hideo Tomonaga, a submarine architect. The U-234 was informed of Hitler's suicide (May 1). Naval Highcommand ordered all German submarines to observe a ceasefire (May 4). The order to surrender was then given (May 8). The captain of the U-234 at this time arrested the Japanese officers who subsequently attempted suiside with sleeping pills. The German officers then discussed if they should surrender or proceed to Japan. They decide to surrender and to kill the Japanese who had botched their suiside attempt. This meant that they could not talk to the Americans about the purpose of the uranium oxide. Their bodies were discaded at sea. The captain then contacted naval authjorities in Halifax to arrange a surrender. Finally he decided to surrender to the Americans. The USS Sumter escorted the U-234 to Portsmouth. The U-234 was interned at Portsmouth (May 19). There the Americans learned for the first time that radio-active uranium oxide was aboard. What the Americans did not know was if other U-boats had gotten through to Japan with uranium an nuclear technology. This may have influenced the subsequent American decession to use the bomb on Japan. The nature of the uranium and disposition by the U.S. Navy is shrouded in mystery. Using lead contianers with gold lining was needed because uranium is highly corrisive. This and the lead cannisters susts it was a very high grade enriched uranium. [Hydrick, p.7.] The level of enrichment refers to the percentage of the U-235 isotope. As far as we know, the Government has never released the level of enrichment which would provide an insight into the German atomic program. It is generally accepted that the Los Alamos team was having trouble obtaining the amount of uranium needed for a bomb. [Goldberg] Some authors believe that the uranium on U-234 was a godsend for the American Manhattan Project and used by the Americans for the bombs used on Japan. Lt. Col. John Lansdale Jr. who worked with the Manhattan Project as a security officer and was responsible for tracking uranium confirms that the German uranium was used to build the bombs dropped on Japan. [Broad] Some authors also wonder about the "infrared proximity fuse" and wether it was actually a fuse connected with the atomic program. Many of these quetions are still unanswered. But the fact that the Germans had enriched uranium strongly suggests that they had made more progress in building a bomb than is recognized by most authors. And it also raises questions about the Japanese atomic bomb program and the extent of cooperation between the Axis allies.

The Boat

The U-234 was a very large mine-laying U-boat--the XB type mine layer. Because of its size it was converted as a Japan transporter, thus becoming an undersea freighter to carry a much larger cargo than a standard U-boat. Even so it held only a fraction of the cargo of a surface merchant vessel.

The Mission

The U-234 was dispacted to Japan with a cargo of German high-tech equipment. We do not know precisely who gave the orders for the mission. We would guess that Hitler may have been conulted, but we have no direct evudence of this.

Cargo

The cargo included drawings, a Me-262 jet fighter in crates, air defense radars and jet engine equipment. What made the U-234 especially interesting was 80 gold-lined lead cylinders containing 560 kilograms of uranium oxide marked "For the Japanese Army". Using lead contianers with gold lining was needed because uranium is highly corrisive. Some authors also wonder about the "infrared proximity fuse" and wether it was actually a fuse connected with the atomic program. Many of these quetions are still unanswered. There is very limited cargo space even aboard this cargo U-boat. Thus only items of the highest priority would have been loaded.

Voyage

The U-234 departed Kiel headed for Kristiansand, Norway (March 25, 1945). The ship departed Norway for Japan (April 16, 1945). Cpt. Fehler received cease-fire orders (May 4). He decided to surrender to the Americans. The Captain claimed to know nothing about the uranium. The U-234 was informed of Hitler's suicide (May 1). Naval Highcommand ordered all German submarines to observe a ceasefire (May 4). The order to surrender was then given (May 8). The captain of the U-234 at this time arrested the Japanese officers who subsequently attempted suiside with sleeping pills. The German officers then discussed if they should surrender or proceed to Japan. The captain then contacted Allied naval authjorities in Halifax to arrange a surrender. Finally he decided to surrender to the Americans. The USS Sumter escorted the U-234 to Portsmouth. The U-234 was interned at Portsmouth (May 19).

Passageners

The U-234 had Japanese and German weapons specialists aboard. Also aboard were two Japanese officer--Air Force Colonel Genzo Shosi, an aeronautical engineer, and Navy Captain Hideo Tomonaga, a submarine architect. The Germans decided to kill the Japanese who had botched their suiside attempt. This meant that they could not talk to the Americans about the purpose of the uranium oxide, although it is not clear how much they knew. Given their backgrounds they probably did not know a great deal. Their bodies were discaded at sea. There were also two German weapons experts. Ulrich Kessler was a Luftwaffe general was a Prussian-born diplomat and military strategist who began his military career as a naval officer. He resigned his commission (1933). He joined the new Luftwaffe and commanded Stuka squadrons operating in Poland, Norway, and France (1939-40). He subsequently commabded special bombing attaxk squadorns in Norway. Kessler apparently did not get along with Luftwaffe commabnder Goering. There are rumors he was active in anti-Hitler resistance activities, including the July bomb plot. Kessler was on the U-234 to advise the Japanese in combat tactics using squadrons of ME-262 and ME-163 aircraft against Allied bombers. Submarine officers would not have know about Germany's secret nuclear program and there is no reaon to think they knew how the uranium was to be used. Kessler is a different matter. He may well have know, perhaps even briefed, but there is no way of knowing this. When the U-234 surrenderd in Portsmouth, Kessler surrendered with a smart salute. One source contends that it was Kessler who convinced Cpt. Fehler to surrender. One source suggests this was the case. [Grover] As senior officer, he would have had some influence and may have explained the significance of the uranium. Kessler claimed during interrogation that he had voluntered for the assignment as way of getting to Argentina. This could be true as many Germans wwre seeking refuge there. This is interesting because it is an open question to what extent the Argentines allowed U-boats to land or reprivision there.

The Uranium

It was at Portsmouth that the Americans learned for the first time that radio-active uranium oxide was aboard. The nature of the uranium and disposition by the U.S. Navy is shrouded in mystery. The only pupose for the uranium oxide given the state of Japanese nuclear research would have been a dirty bomb. This and the lead cannisters suggest that the uranium oxide was a very high grade enriched uranium. [Hydrick, p.7.] The level of enrichment refers to the percentage of the U-235 isotope needed to achieve fission. As far as we know, the Government has never released the level of enrichment which would provide an insight into the German atomic program. We have seen various assessments from unprocessed to highly enriched. Unprocessed is not accurate because uranium oxide is a processed form. Just how enriched it was we are not yet sure. One source tells us that it was highly enruiched--65-70 percent. [Griover] This would be near bomb grade ahd even without a thermo-nuclear devise could be used for deadly dirty bombs. If the Germans had suceeded in enriching uranium, this strongly suggests that they had made more progress in building a bomb than is recognized by most authors. And it also raises questions about the Japanese atomic bomb program and the extent of cooperation between the Axis allies. It is generally accepted that the Los Alamos team was having trouble obtaining the amount of uranium needed for a bomb. [Goldberg] Some authors believe that the uranium on U-234 was a godsend for the American Manhattan Project and used by the Americans for the bombs used on Japan. Lt. Col. John Lansdale Jr. who worked with the Manhattan Project as a security officer and was responsible for tracking uranium confirms that the German uranium was used to build the bombs dropped on Japan. [Broad]

Americam Assessment

What the Americans did not know was if other U-boats had gotten through to Japan with uranium an nuclear technology. This may have influenced the subsequent American decession to use the bomb on Japan.

Sources

Goldberg.

Grover, Wayne. E-mail message, April 7, 2011.

Hydrick, Carter P. Critical Mass: The Real Story of the Atomic Bomb and the Birth of the Nuclear Age.

Created: 1:00 AM 4/6/2011
Last updated: 2:44 AM 4/8/2011