09V/09VI (095/096) Nuclear Submarine Thread

Air Force Brat

Brigadier
Super Moderator
I'm going to guess these look like buoyancy calculations based off arbitrarily uniform volumes for displaced water with rough sub sizes. Don't think this is how diving depth on subs work though.

I think you're right, but what was he trying to say??
 

Brumby

Major
Which are also difficult to weld, but very strong... the problem with Titanium is another matter altogether, Titanium cracks at the weld considerably more often than steel, but make no mistake, HY-100 is also very difficult to get a good clean weld on...

Why don't you elaborate on some of the design factors of the Russian sub that allows it to dive considerably deeper, feel free to include any observations on safety. Could or does China incorporate those design elements into their subs??

Titanium is both expensive and very difficult to work with. Whilst it initially allowed the Russian subs to go deeper, every time titanium is compressed it becomes more brittle. In effect, every time a titanium-hulled sub goes deep, it reduces how deep it can go next time. Progressively the Russian submarines had more fatigue cracks and became noisier as the cracks would rub against each other. The story is, the Russians never solved the creep fatigue interaction problem associated with Titanium. The Russians simply traded off depth for longevity and noise.
 

Air Force Brat

Brigadier
Super Moderator
Titanium is both expensive and very difficult to work with. Whilst it initially allowed the Russian subs to go deeper, every time titanium is compressed it becomes more brittle. In effect, every time a titanium-hulled sub goes deep, it reduces how deep it can go next time. Progressively the Russian submarines had more fatigue cracks and became noisier as the cracks would rub against each other. The story is, the Russians never solved the creep fatigue interaction problem associated with Titanium. The Russians simply traded off depth for longevity and noise.

So what kind of steel do the Chinese use on their latest boats? and have they gone a completely different direction on own nuke boats as far as design?
 

Tam

Brigadier
Registered Member
Not sure how Titanium ever came to the thread, Chinese subs all use steel. I never heard them using Titanium. Russian participation or technical assistance to Chinese submarines are practically non existent. Russian submarine technology is something the Russians keep to themselves close at heart.

However, do note that the Japanese use very deep dive tactics with their SSKs, and that is something the Chinese will not just stand around and watch, which is why the Yuans are trying to beat depth records on their own.
 

Brumby

Major
So what kind of steel do the Chinese use on their latest boats? and have they gone a completely different direction on own nuke boats as far as design?

I can't vouch for its reliability but the Chinese supposedly uses very advanced steel that is equivalent to HY114. Naturally diving depth is a function of steel strength, wielding technique and hull design. it should be noted that when talking about diving depth there is a need to distinguish between operating and crush depth. The rule of thumb in the USN is the adoption of 2/3 ratio between operating and crush depth but is different with other navies in terms of safety threshold..
 

by78

General
Three research papers that could be relevant to the nex-gen nuclear subs. Pardon the large image dimensions. Translating these are beyond my ability, but fortunately English abstracts are available.

P.S. Some fragments of the first paper have been seen before, but as far as I recall, this is the first time the entire paper has been made available.

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by78

General
Analysis of radiated noise of shaft-less pumpjet. This could be relevant for a wide range of underwater vehicles, but I'm putting it here since other threads are not as appropriate. Translating the paper in full is beyond my abilities, but it does helpfully have an English abstract.

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