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I consider it a sign of poor quality writing when the article doesn't explain a technical concept early on. What is Air Independent Propulsion? The article neve

I consider it a sign of poor quality writing when the article doesn't explain a technical concept early on. What is Air Independent Propulsion? The article never even makes it that clear. Paragraph six starts as if it is about to explain it, but then it tells you that Sweden uses subs powered by a Stirling engine. Is it the same thing? Do AIP submarines always have this type of engine, or just Swedish ones? The reader never knows.

nradov 5y ago
AIP is an operational concept, not a specific technology. Several different types of power sources have been used. The most common approaches today are fuel cells and Stirling engines, both of which rely on fuel and liquid oxygen. https://en.wikipedia.org/wiki/Air-independent_propulsion https://en.wikipedia.org/wiki/Air-independent_propulsion
ChuckMcM 5y ago
I certainly agree with this. "Air Independent" in this case means that the propulsion system doesn't need air from outside the submarine. Batteries are an "air independent" system but this is talking more about things like fuel cells or Stirling engines. The cool thing about Stirling engines is that there isn't a "bang" associated with the power stroke, that makes them quite (unlike diesel engines). Fuel cells obviously generate power from the catalyzed combination of chemicals, and so are also silent. As the article points out they are quiet but their range is limited so they are good for patrolling your coast, not great for going across the ocean stealthily. I was impressed that the Gothard class was getting 75kW from their Stirling engine. I had not known that there were production engines greater than 50kW. So that was new to me.
- denton-scratch 5y ago
  Regarding silence: Submarines and anti-sub destroyers aren't using their sonar to listen for the sound of the motor. They're listening for cavitation from the screws. Motors are already silent-enough. The problem for stealth is how to make a silent mechanism for moving water.
AdrianB1 5y ago
And there are factual errors like the pump noise for nuclear plant cooling, that was a problem 40 years ago for some countries that were not able to design a convection-based system.

nradov 5y ago

AIP is an operational concept, not a specific technology. Several different types of power sources have been used. The most common approaches today are fuel cells and Stirling engines, both of which rely on fuel and liquid oxygen. https://en.wikipedia.org/wiki/Air-independent_propulsion https://en.wikipedia.org/wiki/Air-independent_propulsion

ChuckMcM 5y ago

I certainly agree with this. "Air Independent" in this case means that the propulsion system doesn't need air from outside the submarine. Batteries are an "air independent" system but this is talking more about things like fuel cells or Stirling engines. The cool thing about Stirling engines is that there isn't a "bang" associated with the power stroke, that makes them quite (unlike diesel engines). Fuel cells obviously generate power from the catalyzed combination of chemicals, and so are also silent. As the article points out they are quiet but their range is limited so they are good for patrolling your coast, not great for going across the ocean stealthily. I was impressed that the Gothard class was getting 75kW from their Stirling engine. I had not known that there were production engines greater than 50kW. So that was new to me.

denton-scratch 5y ago
Regarding silence: Submarines and anti-sub destroyers aren't using their sonar to listen for the sound of the motor. They're listening for cavitation from the screws. Motors are already silent-enough. The problem for stealth is how to make a silent mechanism for moving water.

AdrianB1 5y ago

And there are factual errors like the pump noise for nuclear plant cooling, that was a problem 40 years ago for some countries that were not able to design a convection-based system.