Rumoured "mini-nuke/diesel" Submarine SSK-N(?) thread

[Iron Man]

I need an article to show that buoyant force causes flotation, higher buoyant force means faster flotation and net buoyancy can be changed by adding or reducing weight???

Adding or reducing weight will get you what, a few seconds? A minute? These things point up to point the missile up so there has to be a net upward buoyancy. Also, while you could increase the time it takes to float to the surface by some measure, remember we're talking about an SSK, not an SSN that can fire and then turn, dive, and burn at 30+kts.

BTW, yes you do need to find an article which suggests there is some kind of intentional delay between firing a capsule and firing the missile from the capsule, because you need to provide a doctrinal justification where it makes real world actual military tactical sense for this delay, not just theoretical reasons you thought of in your head. I don't even know of an SSN that intentionally incorporates a delay between capsule firing and missile firing, which makes it even more suspect for me that an SSK would attempt this.

KSS-3 and Taigei are of comparable displacement in the 4k ton regime +/- 10%. So it is more of a doctrinal difference than a hard physical limitation or something that has a hard advantage vs disadvantage. However even for KSS-3 the VLS are mostly for land attack.

4,000t is at the high end range of SSKs (and the bottom range of SSNs) so that's not a strong case there.

 

[FairAndUnbiased]

Adding or reducing weight will get you what, a few seconds? A minute? These things point up to point the missile up so there has to be a net upward buoyancy. Also, while you could increase the time it takes to float to the surface by some measure, remember we're talking about an SSK, not an SSN that can fire and then turn, dive, and burn at 30+kts.

BTW, yes you do need to find an article which suggests there is some kind of intentional delay between firing a capsule and firing the missile from the capsule, because you need to provide a doctrinal justification where it makes real world actual military tactical sense for this delay, not just theoretical reasons you thought of in your head. I don't even know of an SSN that intentionally incorporates a delay between capsule firing and missile firing, which makes it even more suspect for me that an SSK would attempt this.


4,000t is at the high end range of SSKs (and the bottom range of SSNs) so that's not a strong case there.

This isn't the gotcha you think it is.

Swim out torpedoes exist and have well known advantages.

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Starting in 2003, the US Navy began the Stealth Torpedo Enhancement Program which aims to upgrade the capability of the existing Mk 48 design by implementing alternative fuel sources including electric fuel cells, and a "swim out" capability, a capability that allows a torpedo to leave the tube under its own power without using a torpedo tube's noisier compressed air-launch system.

Swim out capsules also exist.

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So yes at least the theoretical capability is there, if not deployed.

 

[Iron Man]

This isn't the gotcha you think it is.

Swim out torpedoes exist and have well known advantages.

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Swim out capsules also exist.

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So yes at least the theoretical capability is there, if not deployed.

You forgot to mention that the missile has a range of apparently 19nmi, the tradeoff obviously being that if you put a missile inside a capsule with its own propulsion system, the missile has to be small AF to accommodate the swim-out capability of the capsule, both of which have to fit inside a standard torpedo-sized form. Which is why probably nobody else uses it.

 

[tphuang]

I don't have a preference either way: not my decision to make, or something that I'm in a position to lobby for or against in any meaningful manner.

I'm just a casual observer here for friendly and hopefully thoughtful conversations on topics of mutual interest.

I got the idea that this boat might be quieter than (certain) "more traditional SSNs" from a few different places, including this very thread:

There is no reason to think that way

So in your opinion and assessment, would there be more of an use case for VLS integration if this boat is oriented more towards operating in and around the 2IC rather than the 1IC?

no, because DF-26, J-36 and H-6K have it covered pretty well.
Basically, the limits of these platform is about 3000 km away. The VLS targets you'd want to think about are Honolulu and San Diego.

The platform in question appears akin to AIP enabled diesel-electric SSKs, in the vein of the 039C, except equipped with a nuclear powerplant of some sort and without Stirling engines from the looks of things.

Though given that we still don't know exactly what powerplants will be incorporated, I'm happy to defer to more fitting terminology, especially once more fidelity is established on the internals of this boat.

However, said nuclear powerplant is apparently, or based on what we might know or believe thus far, unable to provide this boat the speed and endurance typically associated with a "more traditional" SSN.

This inevitably leads us to the question: is the nuclear powerplant in this instance the primary source of power or an auxillary source of power or better characterized as something else altogether?

It is the primary provider of energy. There is no point having a nuclear reactor in there if it can't provide a lift in performance.

The reduction gear, Stirling engine and larger electric motor/drive are all noise generators to different degree. We use 10 knots as the max cruising speed here, because speed to power is 3rd degree power relationship. So if, 25MWe might be required for 30 knots cruises for 4000t sub, then close to 1MWe is needed for 10 knots. There is a limit to how large Stirling engine can get. Back in 2021, they built what was then the largest Stirling engine at 320 kW

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This was what was said at the time. Clearly indicating MW Stirling engine is designed to be paired with nuclear energy and a sodium cooled fast reactor, which they have also spent a long time working on

The Stirling engine is a closed-cycle reciprocating power machine that takes heat supply from external sources, the press release explained, noting that the engine can be combined with any kind of heat source, either conventional or nuclear energy, in many configurations.

A megawatt-class Stirling engine is tightly structured, has a simple system and can be started quickly and configured in modules. These will be significant advantages of the Stirling engine, the CSSC announced.

When used together with a sodium-cooled fast reactor, the Stirling engine can eliminate the risk of sodium-water reaction making it also a very safe choice.

In 2023, they actually tested Stirling thermoelectric converter in orbit

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It was said at the time

When paired with a

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as a

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, Sterling engines could allow for long-duration stays on the moon and Mars, augmenting solar power, batteries, fuel cells, and other conventional power source

so the key is nuclear power is constant and they've managed to developing Stirling engine large enough to somehow power at least part of the space module.

Why we want to use Stirling

Stirling thermoelectric converter reduces all that stuff on the right side. Cuts a lot of noise making part.

 

[FairAndUnbiased]

You forgot to mention that the missile has a range of apparently 19nmi, the tradeoff obviously being that if you put a missile inside a capsule with its own propulsion system, the missile has to be small AF to accommodate the swim-out capability of the capsule, both of which have to fit inside a standard torpedo-sized form. Which is why probably nobody else uses it.

A swim out missile canister doesn't need to go far, in fact it doesn't need to go much at all, it just has to break surface with a delay to greatly increase the positional uncertainty of the launcher.

A stationary time delay of merely 30 min at a distance of 50 km and a speed of 20 kph (10.7 kts) increases area of uncertainty by 43%.

 

[Iron Man]

A swim out missile canister doesn't need to go far, in fact it doesn't need to go much at all, it just has to break surface with a delay to greatly increase the positional uncertainty of the launcher.

A stationary time delay of merely 30 min at a distance of 50 km and a speed of 20 kph (10.7 kts) increases area of uncertainty by 43%.

I mean, are you expecting the target to just stay still for 30minutes? Because I can guarantee you the target ship won't be traveling at 10.7 kts. And if the range of your mini-missile is already a piddly 19nmi to begin with, you're going to have problems that physics can't solve....