> I assume no one is staging ASW operations against Narco submarines.

Subs on covert missions don't exactly fly flags. I find it hard to believe there's anti-sub tech that can tell if a given vessel is being operated by cartel members or the Russian navy.

Well, yes, if it's a high-tech vessel then it's obviously some nation-state. But if you know your enemy always goes after high-tech subs and ignores low-tech subs, Russia can simply build a fleet of low-tech subs and use them, knowing the NATO commander on duty will take a glance at the sonar readout and say "Ahh it's those drug smugglers again, law enforcement's business, not our problem, we do nothing, boys."

Point is, they should be doing ASW operations against the Narcos, if they can't tell without boarding the sub whether it's the Narcos or the Russians.

While it's probably impossible for the Narcos to build a Russian-looking sub, I'm sure it'd be pretty easy for the Russians to build a Narco-looking sub. And the Russians have quite an incentive to do so if, as you assert, "nobody's staging ASW operations against Narco submarines."

Errr, this is very different, but not because of the submarine.

Modern ASW[1] is based on the idea that Russian subs come from Russian bases. US and NATO submarines (and airplanes and ships and undersea sonar arrays etc.) pay a lot of attention to those bases. They are constantly looking for anything coming out of those bases, and then they can follow and track them across the ocean. But saying "somewhere in the Atlantic ocean there is a submarine, let's go find it" is not how modern ASW works. Think of it like looking through a telescope- in order to see something you have to shrink your field of view a lot, but when you narrow your field of view you can look pretty clearly at that one spot. The trick is cuing to point the telescope at the right spot. That's where the difference between a Navy and drug smuggling organization becomes clear.

Drug smuggling submarines are, at least as far as I am aware, generally built in situ on random uninhabited spots, by small groups over the course of a few weeks, then sail to another random spot to deliver their cargo (in Latin America they tend to build on the coast, in Europe they tend to build inland and then truck to the coast). They try to avoid busy shipping lanes or other high traffic areas, try to avoid sending messages via radio or anything like that. The whole point is that there is nothing to cue anyone. That's why drug smuggling submarines are different from real navy submarines. Real navies need facilities that appear to satellites, they need training time which can be observed, they need coordination between ships which means communications, etc. Real navies have to deal with their sailors revealing their locations on VK or Strava. Drug smugglers organize their lives so they don't leave any of that. And when they do slip up and someone can cue the police, the coast guard, or the navy, the submarine gets found just like a real navy submarine does.

[1]: With the very important caveat that over the last 30 years the USN has allowed it's ASW capabilities to atrophy, due to the atrophy of the USSR/RU submarine fleet. But, to look at what they did back when they cared about ASW google: GUIK Gap, SOSUS, SURTASS, Classic Wizard. Those were all about getting ASW assets close to Soviet submarines, and then letting them go to work.

A large submarine with a large crew and a serving of nuclear missiles us indeed hard to conceal, because it needs large coastal facilities.

But IDK if a small submarine with little or no crew, small dive depth, and relatively small payload needs all thus. If a nation-state wanted to deploy it, that could be done way more covertly.

Maybe this is not done because it does not offer any interesting military capabilities. Maybe it is done, but we don't hear about it, because it does offer some interesting capabilities which they don't want to advertise.

> But IDK if a small submarine with little or no crew, small dive depth, and relatively small payload needs all thus. If a nation-state wanted to deploy it, that could be done way more covertly.

In a way, this is tautological. Anything an organized crime group does, a nation state can do trivially, by just paying that crime group (or a similarly-sized and skilled legit group).

The right question is, as you point out, whether it's useful for a nation state to do this. Most of the time it probably isn't - cold war is as much about capability as it is about advertising the capability to the adversaries. If the Russians - or the Chinese, or the Americans - aren't bragging about it, they probably aren't using it in a meaningful fashion.

The North Koreans and Iranians are using very small submarines, similar to the ones under discussion here, probably for similar roles (covert infiltration of people and goods). And similarly, operational security is probably the most important part of their mission as well.

The US fills the same need with the Shallow Water Combat Submersible, delivered close to the target by another submarine in a Dry Deck Shelter. But that's because the US Navy has focused on long range operations.

> "somewhere in the Atlantic ocean there is a submarine, let's go find it" is not how modern ASW works

I imagine not. The whole world could not find a commercial airliner in the ocean. Finding a small submarine would be much harder.

I wouldn't fixate too much on that line of thought.

Perhaps the capability is there but we didn't exactly want to signal to the world we had the capability of doing so. Tinfoil hat I guess.

There's no physically even remotely plausible way for that to work.

> I find it hard to believe there's anti-sub tech that can tell if a given vessel is being operated by cartel members or the Russian navy.

Passive sonar could trivially differentiate between military and civilian engines in the 1980s. And within those, often fingerprint individual vessels by their machinery quirks / lack of maintenance.

And that was without heavy computer pre-processing.

The more cogent point is: why would navies care?

30' length x 10' beam

Modern diesel / AIP examples are in the 200' x 20' range?

There isn't enough room to put credible military capability on a vessel this size. And if you're going low cost, then you want to go fully UUV and elimate crew spaces and logistics altogether.

> There isn't enough room to put credible military capability on a vessel this size.

The USS Cole would probably beg to differ.

I think we can agree that the USS Cole incident turned on rules of engagement more than capability.

In a more wartime footing, I don't think a fiberglass boat filled with 500+ lbs of explosive often succeeds in a suicide attack against a 500' destroyer w/ multiple CIWS mounts.

But "American destroyer vaporizing fishing boat that drifted too close" isn't good PR, hence restrictive RoE.

ASW is highly targeted, there is no way to try to detect submarines over long distances. So unless they want to spend millions and millions targetting exactly these submarines it won't work.

> I find it hard to believe there's anti-sub tech that can tell if a given vessel is being operated by cartel members or the Russian navy.

Without betraying any secrets, the army can know a lot (I mean a lot) about an enemy submarine by its acoustic signature alone. Picking apart a drug smuggling sub from a military sub is child play provided you can actually hear the military sub which is easier said than done.

> they can't tell without boarding the sub

The USA can't board an enemy sub unless it surfaces. That's not what an ASW operation is.

Wouldn't inference based on what they are doing and where they are doing it be pretty useful? Like overwhelmingly so?