This is coolbert:
From a variety of sources to include Sharkhuntes, Freeper, and the Daily Mail:
"Mystery of the lost WWII Japanese mega submarine that could travel around the world 1.5 times before refueling"
"A Japanese submarine [I-400] that was preparing to attack the Panama Canal during World War Two has been discovered off the coast of Hawaii. The 400-foot (122-meter) ‘Sen-Toku’ class vessel - among the largest pre-nuclear submarines ever built - was found by chance in August off the southwest coast of Oahu. It has been missing since 1946 according to scientists at the University of Hawaii at Manoa. The I-400 and its sister ship, the I-401, which was found off Oahu in 2005, were able to travel one and a half times around the world without refuelling."
And now for the rest of the story!
From Harry and Sharkhunters and copied in entirety: [thanks to Harry]
"There is more to this story that they haven't picked up on as yet. The Skipper of this boat was Korvettenkapitaen Tatsunosuke Ariizumi. When he was Skipper of I-8, he was guilty of terrible atrocities including having survivors they had pulled from the water, tied their hands behind them and one by one, forced to run the gauntlet on the after deck between two rows of I-8 sailors armed with knives, machetes and clubs, hacking them to death. If anyone made it through this gauntlet, there was a large Japanese sailor with a rifle with fixed bayonet ready to spear the man and pitch him overboard like a side of beef. Our [Sharkhunters] Member WILLIAM FLURRY (4183-1995) was one of a handful of those who survived this ordeal when his ship SS JEAN NICOLETTE was sunk and the survivors brought aboard I-8 for this torture. He and a handful of others survived because after some had already been killed by the crew and their gauntlet, a destroyer came over the horizon and Ariizumi had to dive to escape. He dived I-8, leaving a dozen or so survivors still on the foredeck, hands still tied behind their backs. Some, like FLURRY, were able to remain afloat until the destroyer rescued them."
In the aftermath of the war the I-400 captured by the U.S. Navy as a war prize, Captain Ariizumi aboard, his disappearance and alleged death circumstantial and intriguing. Again, thanks to Harry and Sharkhunters:
"An American prize crew took over the boats [I-400 & I-401] but left a small part of the Japanese crew aboard to operate the submarine until they got back to port, now in American hands. The guys in the US Navy prize crew were not aware of these atrocities as they were bringing these boats back to Japan but the ONI did know, and they were waiting to arrest Ariizumi when the boat docked. Surprise! When they went to take him off the boat, Ariizumi was nowhere to be found. The crew explained that in the previous night, Ariizumi had taken his own life and the crew put his body overboard while they were underway. A check of the route they took on their return showed that the boat had passed very close to a point of land, giving way to the speculation that Ariizumi had merely slipped over the side and swam ashore."
Ariizumi either have committed suicide and his body disposed of by the crew, or the man having taken his chances with the sharks and tried to swim ashore. Gone but not forgotten, even many decades later.