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> I have to ask why you don't have a ton of unmanned drones down there. Literally remove the need to move somewhere for the people on board. https://en.wikiped

> I have to ask why you don't have a ton of unmanned drones down there. Literally remove the need to move somewhere for the people on board. https://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water https://en.wikipedia.org/wiki/Electromagnetic_absorption_by_... It's extremely hard to communicate long distance underwater, especially to do so discreetly.

taeric 2y ago
You presume it has to be incredibly long range? I'd be surprised if that is necessarily the case. Could also flat out do cables to many of them at rest. Is it fool proof? Almost certainly not. It doesn't have to compete with perfect, though. Just with what we have right now.
- masklinn 2y ago
  > You presume it has to be incredibly long range? No. But you seem to presume engineers working on underwater communication are brainless morons.
  - taeric 2y ago
    No, I presume most of the press is brainless morons when it comes to talking about what the military is likely doing.
    - AnarchismIsCool 2y ago
      I assure you, you realize very quickly that most of military procurement are also brainless morons when you have to talk to them. There's a big disconnect between the military and actual engineering. Yes, that one magic Xilinx part is cool, but you don't need to blow $10k extra on literally everything you buy. They suffer buzzwords and fads the same way everyone in civilian C suite does.
      - taeric 2y ago
        Ha! Fair. I should have scoped my statement largely to arm chair quarterbacks on the internet. With the full understanding and endorsement of what that implies about my contributions! :D
- hwillis 2y ago
  > You presume it has to be incredibly long range? EM waves fall off exponentially inside a conductor like saltwater. A 1 kHz wave has a skin depth of 8.75 meters, vs the Virginia class' 10m width. A signal from the front to the back of the submarine would be attenuated by 10 million times. Note that this is in addition to the normal problems with antennas. Your home router transmits at <100 mW. Say you spent a ton of money and made a super sensitive receiver that could operate from 140m on the low SNR of your router. In order to receive the same power at 140m on 1 kHz, you would need a 1 megawatt transmitter. It would be dumping 60% of its power in the first 8.75 meters of water. Not quite enough to boil it, but not far off. That's your first problem. The second problem is that the wavelength of a 1 kHz signal is 299.8 km. Antenna effectiveness also falls off exponentially with size, and the smallest antennas are maybe 10% of the wavelength. A 1 km antenna does not work well for 1 km, and even then you have to let out a buoy with a long cable- which is how current submarines do it. The third problem is that if the drones are 10s of km or less away from the sub, there's no point. That means you know where the sub is. The problem is knowing where to aim active sonar or drop depth charges, not aiming.
  - taeric 2y ago
    This is assuming I think you have to have radio communication with the drones at all times? I'd assume more that you have tethered trenches scattered throughout the ocean that you care about and can dispatch an absurd number of drones at will. No need to keep them moving on a regular basis. My general thought there was more that keeping an absurdly large fleet of mostly inactive drones a bit more hidden is almost certainly easier than keeping anything in motion and constant communication hidden. Is it necessarily a good idea? Probably not? I was only poking at the "first principals" taking the assumption of constant radio communication as a given. Why? We don't even assume that for submarines with people on them. Which, yes, we have people there so that they can think and respond with situational awareness to events. And I'm fully agreed that we don't want to jump straight to AI to replace people completely. But I also don't know why you wouldn't build a bit more smarts into deployments? And fully expect some of this to happen. (Realistically, I'm largely describing what science fiction used to imagine mine fields are like in the ocean?)
robocat 2y ago
> It's extremely hard to communicate long distance underwater, especially to do so discreetly. How does existing submarine cable infrastructure carry communications to subs? Low-frequency AC current in the shield, data picked up magnetically?
- 0_____0 2y ago
  ELF https://en.m.wikipedia.org/wiki/Extremely_low_frequency https://en.m.wikipedia.org/wiki/Extremely_low_frequency
- hwillis 2y ago
  Sound waves. Acoustic waves travel much farther and there are transmitting stations underwater. Contrary to the other reply, ELF is not used and is impractical: https://en.wikipedia.org/wiki/Project_Sanguine https://en.wikipedia.org/wiki/Project_Sanguine For VLF you can drag a very long antenna behind you, but most submarines just launch a buoy with a normal antenna to the surface and a fiber connection to allow them to stay below the surface. https://www.navalnews.com/naval-news/2022/04/communication-antenna-a-key-system-of-modern-submarines/ https://www.navalnews.com/naval-news/2022/04/communication-a...
  - 0_____0 2y ago
    I did notice the bit in the Wikipedia article where they mention the US station isn't used for submarine comms anymore. Thanks for the higher quality info.
deleted 2y ago
[deleted]
evoke4908 2y ago
If you're launching a fleet of drones, discretion is probably not a major concern. A coded sonic pulse could have exceptionally long range. Sure your enemies would detect it, about half a second before they detect the drones. A more practical concern is simply temperature and how long the drone's power supply can survive in the cold ocean.
- baranul 2y ago
  Drones that sound like, act like, or maybe look like whales, might be the answer. If the adversary can't tell if its a whale or drone, likely to force them to waste a lot of resources and/or ammunition.
  - etiam 2y ago
    It's a compelling picture, but it seems like it would be rather harmful for real whales, and if chances are it's a drone rather than a whale, several actors might choose to fire regardless and find out later. Not that whales are the only option to mimic, but whatever is chosen had better be common enough to make the drones rare by comparison, and stay that way. Jellyfish might be a nice option when conditions permit...
AtlasBarfed 2y ago
Don't whales communicate across oceans with moans?

taeric 2y ago

You presume it has to be incredibly long range? I'd be surprised if that is necessarily the case. Could also flat out do cables to many of them at rest. Is it fool proof? Almost certainly not. It doesn't have to compete with perfect, though. Just with what we have right now.

masklinn 2y ago
> You presume it has to be incredibly long range? No. But you seem to presume engineers working on underwater communication are brainless morons.
- taeric 2y ago
  No, I presume most of the press is brainless morons when it comes to talking about what the military is likely doing.
  - AnarchismIsCool 2y ago
    I assure you, you realize very quickly that most of military procurement are also brainless morons when you have to talk to them. There's a big disconnect between the military and actual engineering. Yes, that one magic Xilinx part is cool, but you don't need to blow $10k extra on literally everything you buy. They suffer buzzwords and fads the same way everyone in civilian C suite does.
    - taeric 2y ago
      Ha! Fair. I should have scoped my statement largely to arm chair quarterbacks on the internet. With the full understanding and endorsement of what that implies about my contributions! :D
hwillis 2y ago
> You presume it has to be incredibly long range? EM waves fall off exponentially inside a conductor like saltwater. A 1 kHz wave has a skin depth of 8.75 meters, vs the Virginia class' 10m width. A signal from the front to the back of the submarine would be attenuated by 10 million times. Note that this is in addition to the normal problems with antennas. Your home router transmits at <100 mW. Say you spent a ton of money and made a super sensitive receiver that could operate from 140m on the low SNR of your router. In order to receive the same power at 140m on 1 kHz, you would need a 1 megawatt transmitter. It would be dumping 60% of its power in the first 8.75 meters of water. Not quite enough to boil it, but not far off. That's your first problem. The second problem is that the wavelength of a 1 kHz signal is 299.8 km. Antenna effectiveness also falls off exponentially with size, and the smallest antennas are maybe 10% of the wavelength. A 1 km antenna does not work well for 1 km, and even then you have to let out a buoy with a long cable- which is how current submarines do it. The third problem is that if the drones are 10s of km or less away from the sub, there's no point. That means you know where the sub is. The problem is knowing where to aim active sonar or drop depth charges, not aiming.
- taeric 2y ago
  This is assuming I think you have to have radio communication with the drones at all times? I'd assume more that you have tethered trenches scattered throughout the ocean that you care about and can dispatch an absurd number of drones at will. No need to keep them moving on a regular basis. My general thought there was more that keeping an absurdly large fleet of mostly inactive drones a bit more hidden is almost certainly easier than keeping anything in motion and constant communication hidden. Is it necessarily a good idea? Probably not? I was only poking at the "first principals" taking the assumption of constant radio communication as a given. Why? We don't even assume that for submarines with people on them. Which, yes, we have people there so that they can think and respond with situational awareness to events. And I'm fully agreed that we don't want to jump straight to AI to replace people completely. But I also don't know why you wouldn't build a bit more smarts into deployments? And fully expect some of this to happen. (Realistically, I'm largely describing what science fiction used to imagine mine fields are like in the ocean?)

robocat 2y ago

> It's extremely hard to communicate long distance underwater, especially to do so discreetly. How does existing submarine cable infrastructure carry communications to subs? Low-frequency AC current in the shield, data picked up magnetically?

0_____0 2y ago
ELF https://en.m.wikipedia.org/wiki/Extremely_low_frequency https://en.m.wikipedia.org/wiki/Extremely_low_frequency
hwillis 2y ago
Sound waves. Acoustic waves travel much farther and there are transmitting stations underwater. Contrary to the other reply, ELF is not used and is impractical: https://en.wikipedia.org/wiki/Project_Sanguine https://en.wikipedia.org/wiki/Project_Sanguine For VLF you can drag a very long antenna behind you, but most submarines just launch a buoy with a normal antenna to the surface and a fiber connection to allow them to stay below the surface. https://www.navalnews.com/naval-news/2022/04/communication-antenna-a-key-system-of-modern-submarines/ https://www.navalnews.com/naval-news/2022/04/communication-a...
- 0_____0 2y ago
  I did notice the bit in the Wikipedia article where they mention the US station isn't used for submarine comms anymore. Thanks for the higher quality info.

deleted 2y ago

[deleted]

evoke4908 2y ago

If you're launching a fleet of drones, discretion is probably not a major concern. A coded sonic pulse could have exceptionally long range. Sure your enemies would detect it, about half a second before they detect the drones. A more practical concern is simply temperature and how long the drone's power supply can survive in the cold ocean.

baranul 2y ago
Drones that sound like, act like, or maybe look like whales, might be the answer. If the adversary can't tell if its a whale or drone, likely to force them to waste a lot of resources and/or ammunition.
- etiam 2y ago
  It's a compelling picture, but it seems like it would be rather harmful for real whales, and if chances are it's a drone rather than a whale, several actors might choose to fire regardless and find out later. Not that whales are the only option to mimic, but whatever is chosen had better be common enough to make the drones rare by comparison, and stay that way. Jellyfish might be a nice option when conditions permit...

AtlasBarfed 2y ago

Don't whales communicate across oceans with moans?