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Comment by ckastner | Hacker News Reader

The article references a similar fate experienced by the USS San Francisco [1].

I find seamounts somewhat fascinating; it's so odd that immensely huge features like these are still not yet charted. The Muirfield Seamount [2] is a good example. The surrounding water is 5km deep, but the mount reaches until about 20m under the surface, as an unlucky ship found out.

[1] https://en.wikipedia.org/wiki/USS_San_Francisco_(SSN-711)#Co...

[2] https://en.wikipedia.org/wiki/Muirfield_Seamount

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> it's so odd that immensely huge features like these are still not yet charted

The fact that this was in the South China Sea makes me wonder if the reason it's uncharted is that the Chinese recently created it; for some time they have been building artificial islands in the South China Sea in order to claim that entire body of water as Chinese territorial waters. (It's outrageous that this doesn't get a lot more international attention; it's as if the United States started building artificial islands around the boundary of the Gulf of Mexico in order to declare all of that to be US territorial waters. Imagine the outcry.)

The South China Sea issue does get a fair amount of attention.

It is very unlikely that this is the cause of the Muirfield Seamount. They would have had to artificially create an underwater mountain taller than Mount Rainier to do so. The surrounding water is 16,000 feet deep.

There was this a while ago, in a region not that far away.

[1] https://www.volcanocafe.org/japan-the-fukutuko-oka-no-ba-eru...

[2] https://www.ladbible.com/news/news-ghost-ships-brought-up-fr...

Also other recent volcanic activity in Japan, with news about volcanic ash from underwater volcano blocking harbors.

Maybe similar things happened there, not so visible, and weren't charted because of that, being new?

That seamount was above water until the end of the Younger dryas, and the 100+ meters of sea level rise that came with it. Perhaps it was once a coral reef?

Inconceivable. And I do know what that word means.

Maybe they were saying haha we know where you patrol

The Monroe Doctrine doesn't count?

What do they teach at MIT ?

Your comment reminds me of that scene in The Hunt for Red October managed to slip away from a chasing torpedo--the Russians had "hyper-accurate" maps of the underwater terrain and knew exactly when to turn from the torpedo's path...

The sub movie Hunter Killer applies this as well.

Same same recall. But is it real though.

If you saw it on the big screen or the internet, its real.

Don’t submarines detect echos? When I walk into a room eyes closed, I know whether it is big or not, furnished or not depending on how the ambient noise gets reflected. Surely the sea must be full of noises and even a black spot of noise should be perceivable?

Especially since detection sensibility hs gotten so high with new tech that countries don’t try to hide anymore, but they try to produce fake sounds in other places in the ocean to disturb the detection.

Detecting echoes requires that they’re running active sonar, which announces their presence to everyone and somewhat ruins the raison d’être for submarines. Running passive they can detect surface ships, but not mountains per se.

I know it's not very economical, but perhaps someone could start a submarine cruise? You get some vacationers, use a relatively large submarine so they have some measure of comfort, then sonar your way around a pre-planned public route. Then you have navigational data and sonar scans you can release to the world. Or, even better than releasing (the bankers say to themselves), selling the data.

Why bother even going anywhere? It's a sealed box without windows—who'd know the difference?

can we have some port holes?

Sure. You can see plenty of black water all day long.

Submarines are notoriously bad places to be. The navy actually sets very long enlistment terms for its submarine crews, because the re-enlistment rate is extremely low. Even with nuclear reactors submarines are cramped, noisy, and unpleasant. Removing the weaponry might make it suck less, but it’s not gonna be “luxury”.

Surface soundings or a towed array are vastly more economical.

For uncontested waters, yes. The problems start when one military starts trying to make charts in waters claimed by another country. That tends to become a bit of a problem.

Sure, but if you're conducting the survey from a submarine you're 1) very nearly as detectable (the sonar is pinging like mad, China likely have hydrophones throughout the region) and 2) as noted, your consts, complications, and vulnerabilties have gone up markedly.

Given circumstances, something like a drone ship might be a better option. Slightly less detectable, cheap, and can be deployed in quantity if desired.

https://youtube.com/watch?v=9XoTAvcKgOE

Toward the end of the video (beginning about 4:30) the VP of ocean mapping talks about bathymetry as a major future mission. I note that whilst the surveyor craft has an international-orange sail as the other droneships, the body is battleship grey. I suspect there may be alternatively-liveried mission sails as well.

More on that here: https://www.saildrone.com/tag/bathymetry

Connan seems to be USN Ret.:

https://www.crunchbase.com/person/brian-connon

In fact, I'd put reasonable money on that being a chief mission consideration for the technology. Drop a bunch of these in bad weather --- they'll make good coverage, and it's going to be difficult as heck to get out, spot them, and take countermeasures.

Give it a grey paint-job and maybe drop some radar-absorbing material on it, and they'll be fairly stealthy.

There's no other way than sonar to detect things like mountains underwater?

That's interesting. Seems by now we might have something else that does that. A way to use sonar that obfuscates the source of a ping, underwater lidar, submarine drones, something?

The generally accepted way to detect large geological features underwater, if you're not a survey ship (moving slowly, running multiple loud sonars, etc.) is to have and use accurate navigation charts.

Wretched shortcomings in that regard seem well-accepted as the cause of the USS San Francisco's mishap.

What signal would you send that isn't detectable by anyone but you?

Perhaps a sound signal that's a copy of something naturally occurring, e.g. by sea animals.

That came to mind for me too.

Fleet of small scale autonomous drones? Bonus points if they're water soluble.

An array of tactile antennae/feelers?

Entertaining the idea of a probe sticking out the front led to a realization. The problem is you're never going to stop in time if you're at speed. You need to know well in advance that something's there.

now you’re thinking like a catfish! i like it

To further clarify, unlike the ships of WW II, today US subs mostly exist for a nuclear second strike capability. The strategy assumes the enemy doesn’t know where all the submarine nukes are, so they’re guaranteed to face nuclear retribution if they initiate an attack.

This isn’t true, and, as the article states, this submarine is specifically a fast attack sub. It attacks other submarines and ships. That’s still related to nuclear deterrence, but not in the way you’re saying.

> today US subs mostly exist for a nuclear second strike capability.

I understand that you say “mostly”, but it is not quite true. There are many other mission types US submarines serve.

There are US submarines which provide nuclear second strike capability yes.

There are US submarines which carry land attack cruise missiles. These are mostly used to surpess enemy air defences.

There are US submarines clearly optimised for “special missions” such as insertion of special force units or taping underwater cables.

Then there are US submarines designed to hunt other submarines.

For example the USS Connecticut is a Seawolf-class nuclear powered fast attack submarine. Nuclear powered means that the energy used to propel it forward and power its systems come from a nuclear reactor, it doesn’t necessarily means that it has nuclear armed weapons. ( Some might think that I am stating the obvious here but it is surpisingly common to confuse the terms “nuclear armed” and “nuclear powered”. ) In any case she does not carry the kind of nuclear armed ballistic missiles one would associate with a second strike role.

Doesn't look nearly as much damage as to USS San Francisco though, the idea of the Connecticut having hit a container seemed more likely to me.

The USS Connecticut weighs about 10k tons. A container weighs maybe 10 tons. That sort of collision might or might not even cause damage. But by the law of inertia, the sub would, in even the worst case scenario, barely slow down and you wouldn't have 10 injuries.

The USS San Francisco was going maximum speed. The Connecticut can do 35 knots but judging from the injuries almost certainly wasn't.

It's not the mass difference that matters, but how rapid a momentum transfer your structure can survive.

As anyone who has hit a deer in their car can tell you, that’s not how momentum works.

I recently hit a deer while going about 60-65mph in a fairly heavy campervan (3 100amp AGM batteries + ~30 gallons of water storage and other gear).

It did $10k worth of damage to my front end.

Deer ended up 150-200 feet away in a ditch.

I barely felt it.

Yeah, and if the deer went through your windshield you likely would have been seriously injured. The relative size of the object to the vehicle doesn’t have to be large to cause significant damage or injuries. Just because you are big doesn’t make you invulnerable.

You're certainly right but still missing the point. The 10 injuries were most likely not due to a vulnerable part of the sub. They were likely due to a sudden change in the sub's motion, which wouldn't have occurred had they hit a container.

There a reason why vehicle crash testing is done with a vehicle of comparable weight. If the tests of a Mini Cooper were done with your camper van, there's no way they would get a reasonable safety rating.

A deer weighs maybe pounds 100 lbs. A car weighs maybe 3000 lbs for a 30 to 1 ratio. That sub weighs 1000 times more than a container. That is how momentum works.

If you hit a 10 ton object and _any_ of the collision is inelastic, that is a tremendous amount of momentum to dissipate. It might not change the speed of the sub much, but it could still cause a lot of damage to the hull which could then injure sailors inside.

Wouldn't the submarine sink if the hull was so deformed that it damaged 10 sailors?

Not if the majority of the damage to the sailors came from them being unexpectedly bounced around the corridors. If they weren't expecting it, they weren't strapped in or otherwise secured.

That all depends on the cross section of the impact area. If you'd hit the container in a corner (extremely unlucky) then that would be highly annoying. But subs are made to survive pretty strong impacts, including using the conning tower to ram through ice layers. They're immensely strong compared to regular vessels due to the kind of forces they are exposed to when diving deep.

Not sure about what deer you've been around - but the deer family have hit definitely weighed about two or three times that.

Saying I've remembered since I started driving: If it's a deer, hit it, better than hitting a tree. If it's a moose, hit the tree, better than hitting the moose.

Total ratio is only relevant if you want to know how much the sub/car slowed down. Kinetic energy is more relevant if you want to know the physical damage sustained.

If you shoot a bullet at a tall wall and a shorter wall, the bullet hole will be the same.

Alternatively, a deer will still ruin the front end of a car with 1000X the mass.

The energy of the impact will be 1/2mdeltaV^2 either way.

Depends on the deer. Mule Deer here that you can find the front yard of your house can be 200-300lbs. And depends on what you mean by, "deer". Are you think about reindeer? Elk? MOOSE? Hitting a moose is gunna be a bad day.

Why would someone refer to a moose or an elk as a deer?

Deer, Elk, and Moose are all part of the Cervid or deer family.

Also, in various parts of the world, the names are commonly used for different specific animals, which can be confusing. What's called a Moose in say, Sweden is called an Elk in Britain. But what we call elk in the US are a different species entirely. Elk in the US are another name for the red deer species, which was once considered merely a subspecies.

You have underestimated the weight of a loaded cargo container by more than 50%.

That's a maximum weight, typical containers are maxed out volume wise long before they are maxed out weight wise unless they carry large amounts of steel, and this particular container would have to have been floating submerged which puts a pretty low upper limit on how much it could have weighed.

If a shipping container is partially submerged, I think you should include the mass of the water that is included in the shipping container. Assuming a neutral buoyancy, this would put the upper limit of mass at around 42 tons.

First the container is sealed and it will float. At that point, it will be a hazard to surface navigation, and the Coast Guard, the Navy, ..., will try to recover them or sink them. Or the shipper will.

Once the seals break down, the container will become heavier than water, have negative buoyancy (Archimedes Principle), and sink. As it sinks the pressure will increase and any remaining air will be squeezed out and it will sink faster.

Also, there really aren't that many containers lost overboard (1,382/yr on average) and few are not recovered. There are a lot more sea mounts, about 14,500.

this is the correct methodology (though I dont know shipping container sizes beyond estimating ship heights as 10ft times the number of containers.

As far as I know, the South China Sea is pretty geologically active. So it's possible the seamount got created since the last good mapping

Geophysicist here. No, SCS does not have any active volcano in the ocean basin. The last volcanic activity is around 6 million years ago.

Oh cool, then maybe you can explain why someone said that the it was due to a "dangerous grounds miniplate"? I thought the contention was the bed of the SCS was a thin plate that formed mountains quicker because it moved faster because it was smaller? So maybe the seamount moved?

I'll admit I'm pretty ignorant here, and could have been mislead. Or maybe it's all true and the answer is still "yeah, it only takes 100 millennia, not the usual much longer"

The sort of geological activity needed to create a large seamount (especially within mere decades) would be obvious to any country with a few seismometers.

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