[Seizethecarp]

I continue to be amazed by the globe-spanning Japanese and German submarine technology of that era! The cargo manifest on this sub is mind-boggling both coming and going...to me anyway...except fot the molybdenum because I used to work for the Climax Molybdenum Co. (AMAX) and know of its strategic value as well as that of the tungsten.

http://en.wikipedia.org/wiki/Japanese_submarine_I-52_(1943)

On 10 March 1944, on her maiden voyage, I-52 (Commander Uno Kameo) departed Kure via Sasebo for Singapore. Her cargo from Japan included 9.8 tons of molybdenum, 11 tons of tungsten, 2.2 tons of gold in 146 bars packed in 49 metal boxes, 3 tons of opium and 54 kg of caffeine.[4] The gold was payment for German optical technology. She also carried 14 passengers, primarily Japanese technicians, who were to study German technology in anti-aircraft guns, and engines for torpedo boats.

In Singapore she picked up a further 120 tons of tin in ingots, 59.8 tons of caoutchouc (raw rubber) in bales and 3.3 tons of quinine, and headed through the Indian Ocean, to the Atlantic Ocean.

It is believed that 800 kg (1,000-lbs) of uranium oxide awaited I-52 for her return voyage at Lorient according to Ultra decrypts. It has been speculated that this was for the Japanese to develop a radiological weapon (a so-called “dirty bomb”) for use against the United States (the amount of unenriched uranium oxide would not have been enough to create an atomic bomb, though if used in a nuclear reactor it could have created poisonous fission products).[2]

She was also to be fitted with a snorkel device at Lorient. In addition, 35 to 40 tons of secret documents, drawings, and strategic cargo awaited I-52’s return trip to Japan: T-5 acoustic torpedoes, a Jumo 213-A motor used on the long-nosed FW-190D fighter, radar equipment, vacuum tubes, ball bearings, bombsights, chemicals, alloy steel, and optical glass.

[colorado tanker]

The voyage of the I-52 was monitored. The Japanese Naval Attache in Berlin radioed the boat that because of the D-Day landings her destination was changed to Norway. He also sent coordinates for a rendezvous with a U-Boat. The boat transmitted its position. Of course, the transmission was intercepted. The U.S. Navy sent a hunter-killer task force to intercept. The U-Boat slipped away, but they got the I-52.

The boat was to return to Japan with uranium. Not enough to build an atomic bomb, but enough for a "dirty" bomb.

http://en.wikipedia.org/wiki/Japanese_submarine_I-52_%281943%29

The wreck has been found and there has been an effort for several years to salvage it. Here's some video. That thing was a monster for its era.

http://www.youtube.com/watch?v=-eGSfA4lRQM