That is, if you are going to first principals, 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_...
It's extremely hard to communicate long distance underwater, especially to do so discreetly.
Is it fool proof? Almost certainly not. It doesn't have to compete with perfect, though. Just with what we have right now.
No. But you seem to presume engineers working on underwater communication are brainless morons.
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.
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.
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?)
How does existing submarine cable infrastructure carry communications to subs?
Low-frequency AC current in the shield, data picked up magnetically?
Contrary to the other reply, ELF is not used and is impractical: 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-a...
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.
Jellyfish might be a nice option when conditions permit...
I now realize the other thread is taking my point to be that this is trivially doable. That was also not my intent. My point was simply that "reducing to first principals" is a bit silly if you are going to maintain the requirement that you have a big enough vehicle to sustain a crew. Even a minimal crew imposes some massive design constraints that you don't necessarily have if you reduce the problem down. (In general, oddly, I meant my comment mostly as a criticism of "first principals" thinking on this. Too many of those analyses bring in base assumptions that are often invisible to the people arm chairing it.)
I’m certainly no expert, but I don’t think that’s the case here. Radio waves don’t penetrate water that far. Communicating with an untethered vehicle deep underwater is impossible. At the surface, trivial.
Though, to your point. Not trying to be an expert or to second guess any expertise out there. I was really only meaning to question the "first principals" idea of reducing it to something that still requires radio waves to penetrate deep into the water. There is no need to keep the idea that it has to remain in radio contact with something far away. You would want it to be able to establish contact, and there will be prioritized methods to do that based on plenty of other variables. Not trivial, mind. But there is already nothing trivial about going underwater.
Hooking to previously unhooked tethers (or keeping drone like submersibles tethered over long periods of time), or communicating via radio underwater is just not practically useful. Like ‘tens or hundreds of meters’ type limited range, when kilometers is typical ‘close’ range.
The reason why crews are required (except for limited research/investigation use cases), is because of these communication issues.
To be sure, you need a lot more flexibility for defense that projects farther than you can put a stake in the ground. (Well, tethers in the water, here.) But I would assume you could almost certainly invest in and build both?
If the opponent knows where all the defense equipment is, they can often bypass or destroy it in a first strike too.
And any common tethering point is not only a weak link (since it’s fixed), but a way to find every piece of equipment that interacts with it (since it has a easy to find location).
The exception maybe purely passive equipment, like SOSUS microphones. But drones are going to make noise when operating, and they’ll point to the tethering point - and every other tethered drone even if it’s not yet operating.
The deep ocean is the definition of the ‘dark forest’ problem.
But this discussion is largely silly; as you are arguing against it as being some sort of perfect proposal. I thought it was quite clear I don't even really mean it as a serious proposal. Just as one that goes against "first principals" being some sort of golden blessing that is bound to get good results.
You seem really intent on ignoring these fundamental issues. It’s like trying to argue that habitats on the moon should try to ignore that the moon has no atmosphere.
We can, but why?
And if you didn’t want arguments, well this is obviously the wrong crowd hah.
And yes, as you add in more constraints, you get more difficulties. So, if you want completely clandestine deployment, that will be far harder. But nobody would be surprised to learn that a military base has lots of latent defenses. Why would this be any different?