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And they aren’t even nuclear powered. Since those subs are defensive (defensive attack subs) and don’t need to roam the seven seas, nuclear power wouldn’t offe

And they aren’t even nuclear powered. Since those subs are defensive (defensive attack subs) and don’t need to roam the seven seas, nuclear power wouldn’t offer much. Moreover, diesel subs running electric are very quiet.

Koshkin 7y ago
Why would an internal-combustion piston-thrashing motor be less noisy than a nuclear heat-powered turbine?
- CalChris 7y ago
  Because batteries. You can’t turn off a nuclear power plant and go really silent.
- rjsw 7y ago
  You can turn off the diesel generator. You can't turn off the cooling pumps of a nuclear reactor.
  - jabl 7y ago
    IIRC many modern nuclear subs can shut down the primary circuit pumps and rely on convection at low power, making them pretty quiet.
- missedthecue 7y ago
  A nuclear reactor must always stay "on". This leaves a very minute level of sound that can be picked up using special modern sensor equipment. A diesel motor on the other hand can be shut off completely and on demand, and the submarine can run off their battery which is completely silent.
  - HeWhoLurksLate 7y ago
    Also, nuke subs can (and do) leak radioactivity into the water. IIRC- and I don't have a source for this (might've been thedrive?)- Russia has radiation-detecting equipment onboard their subs that helps them in their hunt to find U.S. subs.
  - agumonkey 7y ago
    so nuclear subs reactors can never be turned off in operation ?
    - missedthecue 7y ago
      Not the cooling equipment that ensures they don't have a meltdown. Those must stay on all day every day.
      - agumonkey 7y ago
        oh obviously ... #facepalm
    - avianlyric 7y ago
      Can’t talk specifically about nuclear subs. But in a normal nuclear reactor once it’s taken sub-critical (fission chain reaction “stops”) still puts out a significant amount of heat. The reactor may be sub-critical but the fuel still experiences some nuclear decay and puts off quite a bit off heat in the process. You need to continually monitor this and run cooling equipment, otherwise Bad Things happen. Interestingly this effect is used in the nuclear “batteries” in some space projects like the Mars rover, Curiosity.
      - agumonkey 7y ago
        oh interesting http://www.about-robots.com/curiosity-rover-nuclear-battery.html http://www.about-robots.com/curiosity-rover-nuclear-battery....
- jacobush 7y ago
  Because it's a damn refined sterling piston-whispering engine. Also what the others said about batteries.
- stevenwoo 7y ago
  For some reason the original article did not link to the article on the same website explaining why. https://nationalinterest.org/blog/the-buzz/how-one-cheap-submarine-sweden-sank-the-us-navy-battle-25639 https://nationalinterest.org/blog/the-buzz/how-one-cheap-sub... The US Navy war gamed against these type of subs and did not win overwhelmingly - they then turned around and rented them from Sweden to develop new strategies. Of course staying away from the coast is a strategy.
  - jacobush 7y ago
    I read "did not win overwhelmingly" was an understatement. Also small subs are good in littoral waters. The smaller, the better.
  - Dahoon 7y ago
    >and did not win overwhelmingly That would be quite the understatement. If USS Ronald Reagan had been sunk in a real war the US would instantly have either lost all interest in further war or use the big red button.
    - lakis 7y ago
      There is also the big button that says "full conventional war". I believe that the US has way more options then retreat or full nuclear war.
- iveqy 7y ago
  it's not. It's a stirling engine, no combustion here. (And no noicy pumps for cooling water as the nuclear subs have)
- deleted 7y ago
  [deleted]
- deleted 7y ago
  [deleted]
- sl-1 7y ago
  The swedish Gotland-class submarines are know for their stealth. This is achieved by using stirling engines and other improvements. See wikipedia on them: https://en.wikipedia.org/wiki/Gotland-class_submarine https://en.wikipedia.org/wiki/Gotland-class_submarine I think the reason that nuclear subs are hard to make quiet is that the reactor needs quite a lot of supporting machinery, which tends to make noise (pumps etc. for cooling), and these can't be quickly shut down. Hence diesel-electric subs can be a lot quieter (but of course can't win in endurance). But a silent sub can still do a lot , especially if it's targets really can't quiet themselves...
- deleted 7y ago
  [deleted]
- exar0815 7y ago
  Because they are diesel-electric. Diesel charges the batteries during snorkelling - afterwards you just use the batteries. Additionally, modern submarines like the german 212A-Class use fuel cells and other air-independent means of propulsion during underwater-cruise. The problem with nuclear submarines is that they are massive and noisy. They need to be constantly cooled and thus require running coolant pumps, which emit audible noise. Also, steam turbines are noisy when running. They cant be cycled as rapidly to full stop and full power, as well as requiring complex gearing to go forwards and backwards. Their only advantage is their near infinite cruising range. The US-ASW-Capabilities are laughable as of today. They are still fighting their soviet counterparts. They are as of now currently unable to find or fight modern diesel-electric submarines approaching their carriers in any form of exercise. Also, the USN relies heavy on Helicopters, which the russians were unable to counter during the cold war. Nowadays, there exist wire-guided Anti-Air-Missiles which can be launched submerged from torpedo-tubes.
  - greedo 7y ago
    Can you provide a link to tube launched SAMs currently deployed? The RN once experimented with Blowpipe MANPADs for a similar role, but to my knowledge no navy is deploying SAMs on their subs. Also, don't discount SSNs in terms of ASW. There's a reason that submariners say the best ASW is another sub. I wouldn't say the USN relies heavily on helicopters for ASW. They don't really rely on anything since they've let these skills atrophy. About the only investment they've made is in the P8. They've shitcanned the S3, shitcanned SOSUS, and will be in a world of hurt if the PRC decides to get serious about subs.
    - exar0815 7y ago
      That would be the example I know of. https://www.thyssenkrupp-marinesystems.com/en/missile-system-idas.html https://www.thyssenkrupp-marinesystems.com/en/missile-system...
- zapttt 7y ago
  because you turn off all the parts with moving fluids. a nuclear you cannot turn off the cooling, i guess.
- thesaint 7y ago
  Diesel electric.. The clue is in the name.
brnt 7y ago
Diesel-electric subs are an underappreciated type. Nuclear is fine for indefinite remote launch stations, but anything tactical and espionage related, you gonna want a sub that's much quieter and can be turned of completely. Hard to find I English sources, but have a look at Dutch diesel-electric subs if you're interested. Played a neat role during the cold war, a role nuclear subs couldn't fulfill.

Koshkin 7y ago

Why would an internal-combustion piston-thrashing motor be less noisy than a nuclear heat-powered turbine?

CalChris 7y ago
Because batteries. You can’t turn off a nuclear power plant and go really silent.
rjsw 7y ago
You can turn off the diesel generator. You can't turn off the cooling pumps of a nuclear reactor.
- jabl 7y ago
  IIRC many modern nuclear subs can shut down the primary circuit pumps and rely on convection at low power, making them pretty quiet.
missedthecue 7y ago
A nuclear reactor must always stay "on". This leaves a very minute level of sound that can be picked up using special modern sensor equipment. A diesel motor on the other hand can be shut off completely and on demand, and the submarine can run off their battery which is completely silent.
- HeWhoLurksLate 7y ago
  Also, nuke subs can (and do) leak radioactivity into the water. IIRC- and I don't have a source for this (might've been thedrive?)- Russia has radiation-detecting equipment onboard their subs that helps them in their hunt to find U.S. subs.
- agumonkey 7y ago
  so nuclear subs reactors can never be turned off in operation ?
  - missedthecue 7y ago
    Not the cooling equipment that ensures they don't have a meltdown. Those must stay on all day every day.
    - agumonkey 7y ago
      oh obviously ... #facepalm
  - avianlyric 7y ago
    Can’t talk specifically about nuclear subs. But in a normal nuclear reactor once it’s taken sub-critical (fission chain reaction “stops”) still puts out a significant amount of heat. The reactor may be sub-critical but the fuel still experiences some nuclear decay and puts off quite a bit off heat in the process. You need to continually monitor this and run cooling equipment, otherwise Bad Things happen. Interestingly this effect is used in the nuclear “batteries” in some space projects like the Mars rover, Curiosity.
    - agumonkey 7y ago
      oh interesting http://www.about-robots.com/curiosity-rover-nuclear-battery.html http://www.about-robots.com/curiosity-rover-nuclear-battery....
jacobush 7y ago
Because it's a damn refined sterling piston-whispering engine. Also what the others said about batteries.
stevenwoo 7y ago
For some reason the original article did not link to the article on the same website explaining why. https://nationalinterest.org/blog/the-buzz/how-one-cheap-submarine-sweden-sank-the-us-navy-battle-25639 https://nationalinterest.org/blog/the-buzz/how-one-cheap-sub... The US Navy war gamed against these type of subs and did not win overwhelmingly - they then turned around and rented them from Sweden to develop new strategies. Of course staying away from the coast is a strategy.
- jacobush 7y ago
  I read "did not win overwhelmingly" was an understatement. Also small subs are good in littoral waters. The smaller, the better.
- Dahoon 7y ago
  >and did not win overwhelmingly That would be quite the understatement. If USS Ronald Reagan had been sunk in a real war the US would instantly have either lost all interest in further war or use the big red button.
  - lakis 7y ago
    There is also the big button that says "full conventional war". I believe that the US has way more options then retreat or full nuclear war.
iveqy 7y ago
it's not. It's a stirling engine, no combustion here. (And no noicy pumps for cooling water as the nuclear subs have)
deleted 7y ago
[deleted]
deleted 7y ago
[deleted]
sl-1 7y ago
The swedish Gotland-class submarines are know for their stealth. This is achieved by using stirling engines and other improvements. See wikipedia on them: https://en.wikipedia.org/wiki/Gotland-class_submarine https://en.wikipedia.org/wiki/Gotland-class_submarine I think the reason that nuclear subs are hard to make quiet is that the reactor needs quite a lot of supporting machinery, which tends to make noise (pumps etc. for cooling), and these can't be quickly shut down. Hence diesel-electric subs can be a lot quieter (but of course can't win in endurance). But a silent sub can still do a lot , especially if it's targets really can't quiet themselves...
deleted 7y ago
[deleted]
exar0815 7y ago
Because they are diesel-electric. Diesel charges the batteries during snorkelling - afterwards you just use the batteries. Additionally, modern submarines like the german 212A-Class use fuel cells and other air-independent means of propulsion during underwater-cruise. The problem with nuclear submarines is that they are massive and noisy. They need to be constantly cooled and thus require running coolant pumps, which emit audible noise. Also, steam turbines are noisy when running. They cant be cycled as rapidly to full stop and full power, as well as requiring complex gearing to go forwards and backwards. Their only advantage is their near infinite cruising range. The US-ASW-Capabilities are laughable as of today. They are still fighting their soviet counterparts. They are as of now currently unable to find or fight modern diesel-electric submarines approaching their carriers in any form of exercise. Also, the USN relies heavy on Helicopters, which the russians were unable to counter during the cold war. Nowadays, there exist wire-guided Anti-Air-Missiles which can be launched submerged from torpedo-tubes.
- greedo 7y ago
  Can you provide a link to tube launched SAMs currently deployed? The RN once experimented with Blowpipe MANPADs for a similar role, but to my knowledge no navy is deploying SAMs on their subs. Also, don't discount SSNs in terms of ASW. There's a reason that submariners say the best ASW is another sub. I wouldn't say the USN relies heavily on helicopters for ASW. They don't really rely on anything since they've let these skills atrophy. About the only investment they've made is in the P8. They've shitcanned the S3, shitcanned SOSUS, and will be in a world of hurt if the PRC decides to get serious about subs.
  - exar0815 7y ago
    That would be the example I know of. https://www.thyssenkrupp-marinesystems.com/en/missile-system-idas.html https://www.thyssenkrupp-marinesystems.com/en/missile-system...
zapttt 7y ago
because you turn off all the parts with moving fluids. a nuclear you cannot turn off the cooling, i guess.
thesaint 7y ago
Diesel electric.. The clue is in the name.

brnt 7y ago

Diesel-electric subs are an underappreciated type. Nuclear is fine for indefinite remote launch stations, but anything tactical and espionage related, you gonna want a sub that's much quieter and can be turned of completely. Hard to find I English sources, but have a look at Dutch diesel-electric subs if you're interested. Played a neat role during the cold war, a role nuclear subs couldn't fulfill.