Comments by "Sar Jim" (@sarjim4381) on "The Japanese Tiger Tank" video.

  1. Thanks for another interesting video. The Japanese had plans for a really huge submarine on the drawing boards in 1944. It would have been nearly 500 feet long, have a submerged weight of about 9,000 and, except for two torpedo tubes and as many as fourteen 25 mm machine guns for self defense, it was strictly a cargo submarine. It had two eight foot hatches and disappearing 10 ton cranes to handle the expected load of nearly 1,000 tonnes of cargo. The Germans badly needed tungsten, tin, rubber, and opium for making morphine. Due to the active fighting on the Eastern and then the Western front as well, the Germans were going through morphine faster than they could produce opium poppies. The Japanese needed the high quality aluminum and steel the Germans were producing, plus plans for the Tiger tanks, propeller and jet aircraft, and German radar. I doubt the idea of shipping a complete Tiger tank to Japan was ever a serious proposition with the I class subs. Needless to say, the Japanese cargo submarines were never built. The Japanese did have one success transporting cargo when they converted the I-351 from a seaplane carrier to an oil tanker. She made a successful transit from Singapore to Japan carrying 500,000 gallons of high octane aviation gas. This could only be produced by former British Singapore refineries because Japanese refineries were built to produce larger quantities of lower octane gas. This was fine for earlier Japanese planes, but not for the larger, higher horsepower liquid cooled inline engines being built from German plans. The I-351 was headed back to Singapore on July 14, 1945 when she was sunk by the US sub Bluefish. I'm sure you already know this, but the only navy to produce pure cargo subs in WWII were the Italians. Only having some antiaircraft machine guns for self defense if caught on the surface by allied aircraft, these 2,100 ton R class boats were built for trade between Italy, Germany, and Japan. They could carry 600 tonnes of cargo and could travel 14,000 miles unrefueled. They were potentially valuable transports, but the only two completed boats were sunk, one by the British sub HMS United and the other by allied aircraft within days of each other in July 1943 before they could complete any missions.
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