The Wreck of I-201 - Japan's Fastest Submarine

Japanese submarine wrecks are a rare breed. Very few have been located, and even fewer surveyed in any detail. In today's video, we'll be looking at one of those few. I-201, an incredibly interesting wreck
Both for the level of preservation, and for the history of the boat. This was Japan's attempt at a fast undersea hunter. Putting everything aside, to try and get the best underwater speed possible.
And they succeeded. Albeit, too late to matter.
The boat was captured and expended as a target, where she lay for decades. Undisturbed until 2009, when I-201 was rediscovered.
Let's look at that, in this video.
Sinking Video:
• Video
Nautilus Video:
• Exploring Japanese Sub...

[@alephalon7849]

I feel that I-201 is something that Jackie Fisher would approve of because it's two things he likes: fast and a submarine. And it's nice that Nautilus was able to provide recent photos that show the changes over time.

[@alexturnbackthearmy1907]

Ah yes, the two things to get fisher on board with whatever you're doing. Ability to hurt ships a lot and being fast.

[@chrisjeffries2322]

Thank you, for sharing this wreck.

[@iangilland1891]

New Skynea video, Sunday morning, and cup of coffee. Life is good.

[@portcityrulez]

I gotta look this sub up. I knew about the i400s but not this sub. Thanks for the video

[@russelljohnson6267]

@@portcityrulez agreed

[@davidmurphy8190]

The I-201 influenced the postwar OYASHIO design which restarted the Japanese submarine design and development process.

[@seldonplanB-24]

I see your channel is almost to 50k subscribers! I know that's a pretty big milestone for creators, so I really hope to see you pass the mark this year or early 2025 🤘

[@yattaran1484]

Thank you for posting this awesome wreck video of ィ-201. I believe Japanese subs were classified according to its size at the time, and there were ィ・ㇿ・ㇵof three class existed. ィ-class was the largest among them.

[@ivoryjohnson4662]

Thank you for an educational experience

[@markpaul-ym5wg]

Thanks brother.Great video.

[@bonaggy]

Just for context; seeing a lot of comments asking why the Allies didn’t hold to I-201 longer than they did. From what I can remember, the Allies had made agreements to share technologies they discovered to help fight the Axis. However, by the end of the war and the growing realisation that the Soviets would be our new enemy, the Western Allies were not so keen to do so anymore. The problem was that the Soviets were getting very forceful in their demands to see recovered enemy technology. Post war it was simple enough to refuse - the new normal was in place. However, before that it was more tenuous given we were still technically Allies - just look at the American and Russian operations to grab rocket scientists before the war’s end. I know this is what caused the I-400 class submarines to be sunk around Hawaii so that the Soviets could be denied access to them. It’s probably the same with the I-201. The sub was evaluated, innovations recorded as quickly as possible, and then the submarine was “denied to the enemy”. Probably explained as destroyed during testing or an accident. That’s my guess, anyway. Hope it provided some food for thought.

[@nigelmorroll3343]

It's always surprising to see markings on wrecks especially when they've been on the sea bed for some time.

[@JLange642]

I know the sub was only in American hands for a short time, but I am really surprised that the Japanese battle flag was not painted over on the sides post war.

[@davidmurphy8190]

Maybe cheap paint was just splashed over the Japanese flag and over the years, it simply washed away.

[@dennisvandermarkt8263]

Awesome stuff

[@jameschenard1386]

At 19 knots submerged it would be almost 2 knots faster than the type XXI. I’m surprised the allies didn’t hold onto it longer.

[@RTFLDGR]

I am surprised the deck guns were not salvaged for war prizes. Some Gunny would have loved to have those. "GET OFF MY GRASS!"

[@3-DtimeCosmology]

I-201 class is cool 😎

[@warspiteschannel4817]

The smaller hole could be a 'dud' torpedo which struck but failed to explode. The size and depth look about right. EDIT... and the 'Cutie' lying nearby could have caused the hole! Warspite

[@patrickmccrann991]

Dive planes were located both fore and aft during this period. Japanese submarines used the same basic control equipment for depth control.

[@flywheel986]

Took lot's of notes of I-201 when designing USS Nautilus. Pretty obvious the Soviet's had the plans as well.

[@outfield1988]

Ship should have been in a museum.

[@tinkertailor7385]

The light is different. The Nautilus is probably using different light globes now... Probably not incandescent filaments, but LED's. Different light spectrum, different colors. The newer footage looks much different. Can't see any oranges or yellows in the marine growth now... The red on the flag is barely discernable. Not because it has faded, but because of the light.

[@SammyNeedsAnAlibi]

Good video, couple of submarine answers for you: the Japanese were making ships with very poor quality of steel from 1943 on after our submarines started sinking all shipping going into Japan, so that explains why the bow broke away so cleanly. Secondly, that's a MK-37 torpedo- what it's doing there I don't know.

[@michaelinsc9724]

Wow! I had not heard of this sub! THANK YOU! I know there's a story behind that torpedo laying on the seabed so close to tge wreck. Would really like to know what happened. I wonder if it caused the hole in the hull, failed to explode, and dislodged during the fall to the bottom?

[@russelljohnson6267]

That would be my guess. American torpedoes of this period were known to malfunction and not explode even if they hit the target. By the end of the war major improvements had been made in this but it still happened occasionally.

[@davidmurphy8190]

There were different homing torpedoes in service with the USN that would have been used in a test shot against a target submarine. If the I-201 was moored on a given spot and using a diesel motor to generate sufficient noise for a homing torpedo to lock onto, then that would have been good for a Mk 19 torpedo. There was a prototype steam-propelled homing torpedo available in the immediate postwar period.

[@patrickmccrann991]

​@davidmurphy8190 David, you can't moor a vessel in 2500 feet of water. No vessel has storage for an anchor/mooring chain for that depth of water. She was towed to the location then cast adrift.

[@benjamintowns9798]

Most subs had both bow and stern plans. The bow plans were typically smaller and used during slow speed s.

[@davidmurphy8190]

The RN had a WW1 a submarine class that was capable of high speeds on surface and while submerged. Tubes only in the bow.

[@geoffreydybongcojr.2667]

LET'S GOOOOO🎉

[@tinkertailor7385]

I think they fired two torpedoes at her but only one exploded.... That's what the small hole is from. It's from the impact of the second torpedo. The dud buckled the pressure hull and the hull imploded at the damaged section as she sank beyond crush depth. There's no other reason for the hole to be there, especially when there's a dud torpedo lying on the bottom near the sunk submarine.

[@stephenfarthing3819]

Hmmm - interesting! So theoretically this submarine I-201 was able to match the Type 21 U Boat for subsea speed - I assume that it didn't, but it perhaps came close! Do tell!

[@jameschenard1386]

At 19 knots it would be almost 2 knots faster. I’m surprised the allies didn’t hold onto it longer.

[@chrisauton4]

The other damage could have been from a second shot that didn't detonate. Maybe the torp at the end

[@briancooper2112]

Dive Dive Dive

[@johnburns9239]

Fast lot of sound under water

[@BHuang92]

The details of the I-201 did not disappear when the Americans seized the sub. The design would go on to directly influence Japan's first post-war sub.

[@davidmurphy8190]

Was that the OYASHIO? She did look like the I-201. Had a good reference book on submarine design and development, but lost it in a move.

[@angloaust1575]

The germans too had similar Design type 21 but none We're ever used

[@wirelessone2986]

This Submarine is amazing and obviously the Soviets copied this.Question:did they get access to another Submarine like the I-201 or did the USA give them access to the design?I know we sunk it but our gov't does crazy stuff

[@ChuckoMountain-fv9yj]

It wasent fast enough......

[@borisbadaxe9678]

Not fast enough 🤔

[@williambalboni2290]

Typical government bunging, sink it then spend tax money to find it to take pictures, does anyone think that's stupid

[@Glenn-em3hv]

Why do these navy idiots always sink or tear apart all these great ships?? Its just a huge waste that makes no sense like the Enterprise of WW2!!!

[@Thomas-p9i1n]

I wonder how many tons of oil r still in all of those ships and what's going to happen when they rust threw

[@Howie-du7ov]

Nobody cares.

[@JoshuaTootell]

Having been a part of a unit 20 years ago that worked to remove oil from a sunken WWII era liberty ship when it started leaking, I can tell you that is not true ​@@Howie-du7ov If that oil has the chance to damage the local ecosystem, which could also impact people's income, they will care.

[@beedalton9675]

Speak for yourself... does exxon valdez ring a bell ya clown??​@@Howie-du7ov

[@pietervaness3229]

Fm : OCEAN TASK-SUPPLY VESSEL CAPT. P. van ESS. ... excellent video , excellent : U / W images X. Hope for more such vids X. Thank you