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

[Andy1974]

Didn't the leak points to a 2500 tons displacement? If true power requirement would be lower than your 4000 tons estimation.

A lot of peeps here is arguing about whether the sub is closer to SSK or SSN, I think it is missing the point. A much smaller sub than 039/040 yet much greater endurance and somewhat improved speed, In gaming terms I think PLAN is going for a new meta here.

The usage of such a system will be much different from SSK or SSN, it enables much different tactics and doctrine for us to pigeon hole it into SSK/SSN. For starter we're looking at a numerous(cheap) and survivable underwater platform that is able to operate in wide and far away areas, what can PLAN do with it?

I agree, the original tweet said this sub is better than conventional subs in every measure. This submarine should be able to beat any non-nuclear sub from Japan, Korea or Europe, being both quieter, faster and longer legged.

With Chinas upcoming full sized nuclear attack submarine, which will probably be a lot faster than the new Virginias, we have a combination that could beat any other combination, potentially.

In other words, the mini-nuke and full nuke combined has the top performance metrics.

 

[enroger]

they are not that quiet and they have very low endurance (designed to operate in Baltics). The quietest SSKs are also the largest ones like the Japanese ones. Also Chinese subs are typically double hull, so they are naturally going to be bigger

you are also sticking a nuclear reactor in a submarine.

Maybe provide some source to the noise level of these subs compared to say Kilo class? The general impression I got was they're pretty quiet. Endurance is less of an issue for SSKN obviously, sure supplies is still limited to sub size but it is still much much superior compared to conventional SSK. Again this is the game changing aspect, small sub with great endurance.

What is the noise level difference between fuel burning sterling engine and nuclear powered sterling engine? Non as far as sterling engines are concerned, maybe some circulation pump noise for the nuke. Personally I think it is quite possible they have 4th gen reactor that does not require primary cooling circuit, I'm sure many does not agree so I'll leave it.

China has been testing mono-hull so I won't just assume double hull as a must

 

[enroger]

I agree, the original tweet said this sub is better than conventional subs in every measure. This submarine should be able to beat any non-nuclear sub from Japan, Korea or Europe, being both quieter, faster and longer legged.

With Chinas upcoming full sized nuclear attack submarine, which will probably be a lot faster than the new Virginias, we have a combination that could beat any other combination, potentially.

In other words, the mini-nuke and full nuke combined has the top performance metrics.

I'm going to be conservative as to the fighting prowess of this sub, being smaller definitely result in less capable sensor and weapon loadout, I won't assume it can trump larger opponent even though it may have some speed advantage.

The greatest value is the strategic freedom in deployment and potentially large number.

 

[tphuang]

Maybe provide some source to the noise level of these subs compared to say Kilo class? The general impression I got was they're pretty quiet. Endurance is less of an issue for SSKN obviously, sure supplies is still limited to sub size but it is still much much superior compared to conventional SSK. Again this is the game changing aspect, small sub with great endurance.

What is the noise level difference between fuel burning sterling engine and nuclear powered sterling engine? Non as far as sterling engines are concerned, maybe some circulation pump noise for the nuke. Personally I think it is quite possible they have 4th gen reactor that does not require primary cooling circuit, I'm sure many does not agree so I'll leave it.

China has been testing mono-hull so I won't just assume double hull as a must

I talk to submariners. It's commonly known that the latest Japanese are the quietest SSKs in the world. Even the Germans are making their subs larger with 212cd.

cooling circuit is not the main source of noise on a nuclear sub. The biggest source of noise are the steam turbines, generators and reduction gears. So on a nuclear-electric boat like in this example, the loudest source of noise is with the steam turbines or stirling engine and with the eMotor. Think about anything that's mechanical and rotate. That probably causes a lot of noise.

In this case, you would want to raft your mechanical machineries. Once that's done, your next step is to mount your other equipments, think about all the noise that large powerful computers might produce. You keep going until your noise is at same level as ocean water.

It's unclear to me why you would want submarine to be small when they already have cost efficient way of building Yuan sized subs.

 

[enroger]

I talk to submariners. It's commonly known that the latest Japanese are the quietest SSKs in the world. Even the Germans are making their subs larger with 212cd.

cooling circuit is not the main source of noise on a nuclear sub. The biggest source of noise are the steam turbines, generators and reduction gears. So on a nuclear-electric boat like in this example, the loudest source of noise is with the steam turbines or stirling engine and with the eMotor. Think about anything that's mechanical and rotate. That probably causes a lot of noise.

In this case, you would want to raft your mechanical machineries. Once that's done, your next step is to mount your other equipments, think about all the noise that large powerful computers might produce. You keep going until your noise is at same level as ocean water.

It's unclear to me why you would want submarine to be small when they already have cost efficient way of building Yuan sized subs.

If you're talking about Soyru class then sure nothing can beat pure battery in noise, but why don't you mention endurance then?

Again, if sterling engine is the main source of noise then SSKN will have zero noise difference with a SSK that is powered by the same sterling engine, I don't know why you keep insisting nuclear powered sterling must be noisier than conventional sterling or am I misunderstanding you? If Yuan was perfectly fine with sterling AIP then why you have issue with nuclear sterling?

Yes rafting is necessary, but you can't apply the rafting requirement of a 100MW power plant to a 10MW power plant, smaller sub => smaller engine => less noise =>less rafting requirement.

You say Yuan is cost effective, compared to what? Smaller sub built by the same shipyard will be even cheaper. I'm simply entertaining the possibility given the leak

 

[Andy1974]

I talk to submariners. It's commonly known that the latest Japanese are the quietest SSKs in the world. Even the Germans are making their subs larger with 212cd.

cooling circuit is not the main source of noise on a nuclear sub. The biggest source of noise are the steam turbines, generators and reduction gears. So on a nuclear-electric boat like in this example, the loudest source of noise is with the steam turbines or stirling engine and with the eMotor. Think about anything that's mechanical and rotate. That probably causes a lot of noise.

In this case, you would want to raft your mechanical machineries. Once that's done, your next step is to mount your other equipments, think about all the noise that large powerful computers might produce. You keep going until your noise is at same level as ocean water.

It's unclear to me why you would want submarine to be small when they already have cost efficient way of building Yuan sized subs.

I thought that this SSKN won’t have steam at all, and potentially natural circulation means almost no noise from the reactor? In other words, there might not be any noisy machinery on this sub at all. If all your machines are quiet there is less need for sound insulation, and rafting could be simpler or simply done away with all together.

Lets say this is true, and also let’s say the reactor isn’t too large in size either, let’s say it’s man sized, then we have the potential to make a skinny sub which is virtually silent.

If it can be really skinny then maybe this mini-nuke could be more like a very large, manned, underwater vehicle than the subs we are used too. In other words, maybe this is not being developed from a Type 039, but rather an already fully automated battery powered very large UUV to which this new engine is being added along with a manned section. After all, this new engine is just a battery charger.

 

[tankphobia]

Imo a mini nuke is still a nuke, I don't think default assuming that the sskn will be much cheaper than a full sized SSN is a valid assumption to make at this point, if they are going to miniaturize everything to fit in a smaller frame the submarine will only be more expensive.

 

[FriedRiceNSpice]

Yuan class is 3600t. 2500 ton would be a skinny submarine like Song. That's really noisy. You don't even have space to raft that. Let alone provision for long deployment and more space for crew members.

Could it be possible the 2500t version is just a POC/technology demonstrator? Any probability his configuration is being evaluated to see if it is viable for application on full sized SSN?

 

[Maikeru]

Could it be possible the 2500t version is just a POC/technology demonstrator? Any probability his configuration is being evaluated to see if it is viable for application on full sized SSN?

Well the demonstrator could be the small sub we saw sailing down the Yangtze about 3 years ago now (and haven't seen since).

 

[BoraTas]

Regarding vibration, if one Stirling engine produces linear vibrations then two Stirling engines can work together, in opposite phases, to cancel out each others vibrations. The mini-nuke has 4 Stirling engines, it is possible they are connected in such a way as to produce virtually no vibrations transmitted to the hull.

Engines long had multiple measures to mitigate multiple modes of vibrations they are producing. Weights on the crank, torsional dampers, use of specific cylinder and firing interval arrangements etc... What you are saying is done by having separate balance shafts in car engines. As you experience none of these fully eliminate vibrations.