In many ways H.I.J.M.S. I-400 was decades ahead of her time. She was the world's largest submarine, with a length of 400 feet and a surfaced displacement of 3,530 tons. Above her main deck rose a 115 foot long, 12 foot diameter, hangar housing three torpedo-bombers. These floatplanes were rolled out through a massive hydraulic door onto an 85 foot pneumatic catapult, where they were rigged for flight, fueled, armed, launched, and, after landing alongside, lifted back aboard with a powerful hydraulic crane. The I-400 was equipped with a snorkel, radar, radar detectors, and capacious fuel tanks that gave her a range of 37,500 miles: one and a half times around the world. She was armed with eight torpedo tubes, a 5.5 inch 50 caliber deck gun, a bridge 25mm antiaircraft gun, and three triple 25mm A/A mounts atop her hangar. The advent of guided missiles and atomic bombs transformed her from an overspecialized undersea dinosaur to a menacing strategic threat. Like Germany's Type XXI U-boat she was too late to influence World War II. From: TOM PAINE'S JOURNAL
TRANSPACIFIC VOYAGE OF THE
After she was taken over from the Japanese on her way home from patrol you can imagine that the I-400 required a massive clean-up from stem to stern. The field day started with all hands moving aboard the U.S.S. Proteus, after which cylinders of fumigating gas were opened in every compartment and the boat sealed. Next morning bushel after bushel of dead rats and cockroaches were swept up. I'd noted with some revulsion on the Ha-boats the occasional rat leaping through a hatch from compartment to compartment, and hordes of scurrying roaches when a light was switched on, but I'd no idea that these boats carried so many verminous shipmates on patrol. If the I-400 had been rigged for dive when the rats and roaches were thrown overboard the Diving Officer would have had to order: Flood two hundred pounds to Auxiliary Tank from sea.
My friend Admiral Joe Vasey, who was "Junior" McCain's (i.e. Senator John McCain's father) Exec on the U.S.S. Gunnel, sent me this description of the condition of the I-400 when the U.S. Navy took over.
Sailing across the Pacific to Pearl Harbor (or through space to the moon) requires a sound plan for fitting out, manning and supplying your ship. The I-400 had no blueprints or Machinery History describing her equipment, no crew's Watch, Quarter & Station Bill, and no Standard Allowance Lists of tools, spares and supplies. It was clear that we'd have to improvise, so we were given wide latitude by the powers that be in readying and supplying our unusual boat for her transpacific voyage. The Euryale's workshops and stores were put at our disposal, and we were authorized to salvage any Japanese spare parts and supplies we needed from the warehouses and caves I'd explored around the Sasebo Navy Yard.
Experienced submariners can imagine the results of opening a trove of untended Japanese stores to the crew of a homeward bound submarine equipped with a cavernous hangar and 12 ton crane. Yes, the I-400 quickly became history's first Undersea Interisland Trader. Overnight our hangar became an armory suitable for a major gun running operation, with stacks of rifles and bayonets from a relatively dry cave I'd spotted. From Japanese uniform buttons and rating badges to rubber stamps and a sampan, down our capacious hatches they went to stock our Submarine War Surplus Store.
The prize crew which had brought the I-400 from Yokosuka had maintained her well, and it didn't take long to put her in shipshape seagoing condition, with vital machinery inspected, overhauled and tested by a responsible crew member. Since we had no plans to dive the boat before a complete overhaul at Pearl Harbor we didn't worry about her malfunctioning snorkel, stiff diving gear or minor defects like leaky hatch gaskets or an inoperative automatic trim system. To conserve the Euryale's supplies we loaded provisions for only 14 days to carry us through the first leg of our passage to Guam, where we'd reprovision for the rest of the voyage to Hawaii. By the end of November we were able to report the I-400 "in all respects ready for sea."
|From: TOM PAINE'S JOURNAL: JULY
1945 TO JANUARY 1946 http://www.pacerfarm.org/i-400/