I-400: The Japanese Submarine... That Was Also An Aircraft Carrier

this video is brought to you by squarespace whether it's your new profession or just a lifelong passion start your journey to website glory with squarespace check out their amazing all-in-one platform through the link and description below more about them in a bit [Music] we're the japanese to thank for many ingenious creations over the years the bullet train the qr code sushi car navigation system emojis and who can forget our favorite adventurous plumbing duo the mario brothers but on a more serious note the japanese are also to blame for the selfie stick why there you go which surprising to me at least was first created all the way back in 1983 but we're gonna let them off for that one japanese ingenuity is nothing new and it goes back decades as a shattered country valiantly picked up the pieces after world war ii and came roaring back and at one point became the third largest economy in the world but this inventiveness was also clearly evident during the second major war of the 20th century as imperial japan looked to shift its borders by a few thousand miles or so the second world war saw some extraordinary japanese military hardware appear including the two yamato class battleships which were at the time the heaviest ever to set sail and well we've already covered them here on megaprojects already and they also made the advanced fighter jet the mitsubishi a6m zero series but the focus of the video today is on the vast submarines that began appearing in 1944. the i-400 class submarines were until the introduction of nuclear ballistic missile submarines in the 1960s the largest submarines ever built which in itself is quite extraordinary but it is still not the most intriguing aspect of these submarines you see what the japanese navy called the sentoku type submarines were technically also aircraft carriers [Music] now i know what you're thinking a submarine aircraft carrier how don't i know about this already well primarily because only three were ever finished towards the end of the war with one even converted into a tanker at the last minute and as much as our imagination wishes it so these were not exactly the colossal uss nimitz but underwater though that would have been very cool capable of only carrying three planes on board these were much more submarines than aircraft carriers but nevertheless they provided a unique threat that has never been repeated since but that's not to say it wasn't trialled before world war ii the germans gave it a damn good shot during world war one when they tested an ff-29 taking off from the deck of a u-boat while between the wars france the uk the us and italy also experimented with having a plane on board mainly for observational purposes and often without much success during world war ii the germans attempted to resurrect the idea but it never really got past the experimental stage and it was their asian allies who took things to a different level [Music] also known as the i-15 class submarines the type b1 class first appeared in 1939 and went on to become the most numerous submarines within the japanese fleet again to call them aircraft carriers might be a bit of a stretch but they did come with a single yokosuka e14yc plane located in a hangar in front of the conning tower which could be launched with the help of a catapult 20 of these submarines were built through the late 1930s up until the end of the war and one of them i-25 was responsible for the only bombing raid on the continental u.s during the conflict on the 15th of august 1942 i-25 steamed clear of yokosuka carrying 676 kilogram that's 168 pound incendiary bombs with the sole intention of starting a large-scale forest fire the japanese had done their research and the two fires in 1933 and 1939 together known as part of the tillamook burn which would eventually destroy 350 000 acres across four major fires between 1933 and 1951 had shown just how destructive these fires could be as luck would have it for the americans at least the bombs dropped close to brookings in oregon and they failed to start a fire mainly due to light winds wet weather and due diligence of fire lookouts that night on a loosely related note this was not the only time the japanese attempted to start forest fires in the continental u.s the fugo balloon bombs were hydrogen balloons filled with either incendiary bombs or anti-personnel devices attached to them that the japanese launched hoping that the jet stream would carry them thousands of miles to their intended targets on the west coast of the united states the effort was largely unsuccessful but one bomb did kill a pregnant woman and five children near blai in oregon as bizarre as these bomb sounds they did represent the first intercontinental weapon and until the british attacks on the falkland islands in 1982 known as operation black buck which we've also already covered here on mega projects the fugo balloon bombs were the longest ranged attacks ever carried out anyway we've gone off track so let's get back to our submarines shortly after the attacks on pearl harbor the japanese sought to hammer home their advantage but it didn't take long for the americans to find their fleet and begin striking back admiral yamamoto commander-in-chief of the japanese combined fleet wanted to begin hitting the u.s mainland with aerial attacks the only problem was that it was too far away for any aircraft to reach and getting aircraft carriers within range would almost certainly be met with fierce resistance therefore he planned to build a series of submarines that would be able to carry at least two aircraft and that could make three round trips to the west coast of the u.s without refueling his ambitious proposal was met with equally ambitious approval on the 17th of march 1942 and why not the americans had been given a good hiding and the japanese were riding high so now is the time to strike the enemy where it really hurt the hull for the first i-400 submarine rather boringly also called i-400 was laid down on the 18th of january 1943 with another four planned close behind and a total of 18 to be built in the coming years but by this point things had already begun to change the japanese navy had met their match during the battle of midway in june 1942 and by march 1943 when admiral yamamoto died the fleet had already lost six aircraft carriers with the death of the admiral the number of proposed i-400 submarines fell from 18 to nine then five and eventually just three now we'll get into more production details on the i-400 in just a moment but first a word from today's game-changing sponsor squarespace look it's the age of creation people are out there on the internet making all sorts of things blogs websites web stores you've either got a great idea yourself or you probably know someone who does and when it's time to move that project from your head to the screen in front of you that's where squarespace comes in it's the perfect 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when you're ready to get started on the next web project of yours big or small if it involves a website it's got to be with squarespace right now you can go to squarespace.com for a free trial and when you're ready to launch your site go to squarespace.com forward slash megaprojects to save 10 of your first purchase of a website or a domain and now let's get back to the submarine [Music] at 120 meters that's 400 feet in length the i-400s were slightly longer than the los angeles-class submarines but a good 50 meters 164 feet shorter than the ohio class they came with a beam of 12 meters or 39 feet and a draft of 7 meters 23 feet while their displacement was 6 670 tons and that was roughly twice that of the american submarines at the time each of these submarines had four 2 250 horsepower engines and carried enough fuel to go around the world one and a half times easily enough for a few secretive jaunts to the u.s west coast they also had a top speed on the surface of 18.7 knots that's about 21.5 miles per hour or 34.6 kilometers an hour and a submerged top speed of 6.5 knots or 12 kilometers now 7.5 miles per hour along with a recorded depth of 100 meters or 330 feet now if you're playing close attention you'll notice that its dive depth was in fact less than its total length meaning that they had to be careful during steep dives on the top deck was a cylindrical watertight aircraft hanger 31 meters 102 feet long and 3.5 meters 11 feet in diameter with a 51 millimeter 2 inch thick rubber gasket to ensure no water could get in the submarine also came with its own mini crane because while the planes couldn't land on the deck of course so the seaplanes would make a splash down before sliding up to the mother ship who would then pluck them up with the help of the crane to then be stowed away it came with an electrically operated hoist and could lift a maximum of 4.5 tons directly above the aircraft hangar were three waterproofed type 96 triple mount 25 millimeter auto cannons with an additional 25 millimeter autocannon just after the bridge it also came with a single long-range type 11 140 millimeter deck gun capable of hitting targets 15 kilometers 9.3 miles away and eight torpedo tubes all found in the bow of the submarine now like many japanese ships at the time the i-400s came with two parallel sets of demagnetization cables running from the stern to the bow plane these were designed to nullify the magnetic field caused by the submarine which could trigger magnetic mines in the area they also carried a special trim system that would allow them to loiter underwater while waiting for the planes to return no doubt a great idea in theory but in practice it was said to be incredibly noisy and it's not clear how often it was actually used another ingenious edition of german origin was the anechoic coating that was applied from the water line to the keel the mixture of gum asbestos and adhesives was said to absorb or diffuse enemy sonar pulses and dampen reverberations from the boat's internal machinery this meant that the submarine should have been much harder to detect while submerged but again it's not entirely clear how useful this turned out to be mainly because they were never fully operational in that way the japanese trusted the germans to make their periscopes and each i-400 came with two 12.2 meter 40-foot long periscopes one for daylight and the other for night during the final days of the war one of the i-400s was fitted with a german supplied snorkel and with this hydraulically raised air intake system the submarine could effectively run its engines and recharge its batteries while remaining at periscope depth [Music] the aircraft launched from the i-400 was the ichi m64 siren a plane designed specifically with its rather unique mission in mind and it remained a secret from the allies until the end of the war this was a two-seat low-winged monoplane with a 1410 igae1b atsuta 30 engine which was a license-built copy of the daimler-benz db-601 as we've seen the axis powers were certainly quite open about sharing technology with fellow would-be rulers of the world it could be folded up nicely to fit into the hangar on the submarine and was launched via a 26 meter compressed air catapult that's 85 feet on the forward deck the launch process was painstakingly practiced by a team of poor that could get an aircraft into the air with just seven minutes notice but this aircraft did need some special attention because their engines couldn't be warmed up on the deck as you would do with a normal aircraft carrier to save time and using another helpful hint from their german buddies the crews heated the engine all to roughly 60 degrees celsius in a separate chamber and pumped it along with hot water through the engine just before launch this meant that the aircraft could be ready to go from a cold start and drastically reduce preparation time in terms of weaponry the siren carried a single 850 kilogram 1870-pound torpedo or an equivalent weight in bombs and a lone 13 millimeter 0.51 inch type 2 machine gun to be used by the observer behind the pilot [Music] only three i-400 submarines were completed and they were far too late in the day to make any meaningful impact on the war the first i-400 was completed on the 30th of december 1944 the second the i-401 on the 8th of january 1945 and the third the i-402 on the 24th of july 1945. the final submarine was converted into a tanker shortly before its completion so technically the japanese only had two i-400s with aircraft capabilities if you know your world war ii history and you've come almost all the way through a video about an obscure japanese submarine class during the second world war i'm guessing that you might have some sort of idea that the war was spiraling out of control for the japanese as they were pushed further and further back in fact such was the collapse of the japanese forces that neither of the operational submarines ever even took part in combat one plan to attack the locks in the panama canal got to the stage of full-scale mock-ups being created and the pilots practicing dropping torpedoes but surely before the attack was scheduled the japanese island of okinawa fell to the americans and the tat and remnants of the japanese navy were ordered back to defend the home islands a second attack was conceived that would target the ulitha us base on the carolina islands in the western pacific where a group of 15 us aircraft carriers had rendezvoused to commence further airstrikes shortly before leaving the missouri naval station each aircraft had two stars and stripes painted over the japanese rising suns on each wing which is a clear violation of the rules of war and went down very badly with the air crew who saw it as dishonorable to fly under the american flag but it did not matter on the 6th of december 1945 the city of hiroshima was left a smoldering wreck by the world's first nuclear attack and three days later the americans followed it up with the second strike on nagasaki six days later the japanese emperor formally announced the nation's surrender and all planned military operations were of course cancelled including the attack on the lithi base there was apparently another mission that the japanese had in the pipeline that would have needed the i-400 submarines operation cherry blossom at night actually has quite a pleasant ring to it but the proposed biological attack on san diego would have been anything but the plan to drop infected flea bombs on the californian city had been scheduled for the 22nd of december 1945 by that point u.s ships were sitting comfortably in tokyo bay [Music] when the u.s arrived in japan they took possession of numerous submarines and other ships most of these were scuttled off the coast of japan after the soviets demanded the right to have a snoop around this technology and no doubt take a few notes the three finished i-400s were sailed back to hawaii where they underwent further inspection before being scuttled when once again their communist allies requested access to the submarines under the terms of the treaty that ended the war the i-400s were sailed off the coast of oahu where they were torpedoed and sent below the waves and into the dark depths of the pacific ocean in 2005 i-401 was discovered by the pisces deep-sea submarines operated by the hawaii undersea research laboratory at a depth of 820 meters that's 2690 feet and in 2013 i-400 was found by the same team at a depth of 700 meters or 2 300 feet its skeletal form was still largely intact its guns still mounted and gradually decay it wasn't until the introduction of the nuclear ballistic missile submarines in the 1960s that the crown of the largest submarine in the world finally passed on the i-400s weren't exactly the greatest submarines and the japanese certainly had much better but they did provide something entirely unique and to this day they remain the only submarines ever created that could hold more than two aircraft so i really hope you found this video interesting if you did please do hit that thumbs up button below don't forget to subscribe or please do check out today's fantastic sponsor squarespace link below thank you for watching [Music] you

Channel: Megaprojects

Views: 126,211

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Id: FMuUOy51IvM

Length: 17min 10sec (1030 seconds)

Published: Thu Sep 30 2021