Seawolf's S6W is natural circulating and also is said to be capable of higher output power with no pump than Virginias.
09V/09VI (095/096) Nuclear Submarine Thread
- Thread starter Hendrik_2000
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well, they are not fully natural circulating, but just allows it to natural circulate at much higher power than other SSNs. If your SSN needs to be going at 30+ knot, then that's too much power for natural circulation. Hence, why Ohio class is fully natural circulating, but Seawolf is not.
Also, pumpjet propulsion also allows for lower transiting noise iirc. So, I guess they are really aiming to lower the noise level at transiting speed (I would guess up to 25 knots for something like 09V). But keep in mind that coolant pumps aren't exactly the loudest component in the engine room. If you can quiet all the other stuff at higher speed, then you can do it for the pumps too.
I used 25 knots in there because I think someone said that Seawolf is quieter at 25 knots than LA class when it's not moving. So, I'd think that's the kind of metric that PLAN would really care about for 09V. Can you get out there at 25 knots and not be detected.
Also, pumpjet propulsion also allows for lower transiting noise iirc. So, I guess they are really aiming to lower the noise level at transiting speed (I would guess up to 25 knots for something like 09V). But keep in mind that coolant pumps aren't exactly the loudest component in the engine room. If you can quiet all the other stuff at higher speed, then you can do it for the pumps too.
I used 25 knots in there because I think someone said that Seawolf is quieter at 25 knots than LA class when it's not moving. So, I'd think that's the kind of metric that PLAN would really care about for 09V. Can you get out there at 25 knots and not be detected.
PLAN has 48+ SSKs in service, they are certainly not going anywhere in the near future.
Also, UUVs cannot do what SSKs do.
AFAIK, maybe in the near future. I recall a Chahuahui episode post 93 mentioned something about fully autonomous hunter killers that is able to fire weapons at enemy ships/submarines and pursuit all fully autonomously and using underwater communications to network with other units, manned submarines and ships.
But I agree with you that manned SSKs are still needed for the foreseeable future, especially when the fleet is replaced by new SSK-Ns for longer endurance patrols beyond the first island chain in the SCS.
Fair enough. However UUV can already perform hunter killer function if we trust the official claims from Chinese media, other than human judgment UUV pretty much out perform SSK in every metric, I don't know how far AI development is doing in this domain.
Seawolf and Virginia do not use natural circulation reactors. Latest American reactors are low flow forced circulation cores. They got their pumps so silent by the 1980s that you couldn't tell if they were working even if you were next to them. Reportedly Admiral McKee went to the facility while the first Seawolf was being built. He put his hand on the pump casing. Told the engineers to start it. They said it was already running.
I wonder if that means Seawolf and Virginia's main noise limiter would only be hydrodynamic noise at high speed given that they could run their reactors at high power levels without ruining stealth.
Hopefully 09V would be at a similar if not better level of technology, given better hydrodynamic optimisation it could be possible to have even higher than expected silent speed now that reactor noise is of little concern.
My understanding is that the key limitation to silence at high speeds (above 20 knots) is propellor cavitation rather than other sources of noise.
Hence we see pumpjets being introduced, which delay the onset of propellor cavitation.
Pumpjets are less efficient, but that doesn't matter if power is provided by a nuclear reactor.
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The other element is that propellor cavitation is delayed the deeper a submarine operates.
If the Type-095 is comparable to a Seawolf, that is a much deeper operating depth than a Virginia SSN.
That implies a Type-095 also has a faster "silent" speed
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Yes and no, flow noise over the hull is a major contributor at high speeds which is why even if you have a pumpjet and perfectly silent ship, going above mid to high 20 kn still will be noisy due to flow around the hull becoming turbulent and detachments at the stern or control surfaces. You could probably use some clever hydrodynamic trick to delay this but it is impossible to fully avoid.
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