[HN Gopher] A U.S. submarine struck an underwater mountain last ...
___________________________________________________________________
A U.S. submarine struck an underwater mountain last month, the Navy
says
Author : nradov
Score : 69 points
Date : 2021-11-02 21:14 UTC (1 hours ago)
(HTM) web link (www.npr.org)
(TXT) w3m dump (www.npr.org)
| ProfessorLayton wrote:
| I find it kind of crazy that the ocean isn't mapped out like most
| of the roads in the world are with street view. I get that sonar
| isn't stealthy and is not great for marine life, but considering
| the budget and capabilities of the U.S. military, I'm surprised
| they haven't gotten that over with as its own mission.
| jcun4128 wrote:
| Some companies are trying some pretty cool tech
|
| https://youtu.be/eR8TQ2rXTbE?t=119
|
| Dang read up on USS San Francisco briefly and ran across this
| tidbit about sonar, dang.
|
| > For those who dont know how tremendously loud it is. It can
| be used to kill enemy divers if they are near your ship. It
| will rupture your lungs at 200 Db and hemorrhage your brain at
| 210 Db, sonar operates at 235 Db ... also affects sea life
| mccr8 wrote:
| The ocean's real big.
| dylan604 wrote:
| Maybe they should try using google earth
| WillPostForFood wrote:
| An interesting aspect to the story is that it looks like China
| forced the Navy to disclose details the accident publicly
| accusing the US of a cover up.
|
| https://www.military.com/daily-news/2021/10/29/china-accusin...
|
| I was worried it was a collision with a Chinese vessel.
| Communication was poorly handled by the Navy.
| JaimeThompson wrote:
| "US Pacific Fleet released a press statement on the submarine
| incident five days after the collision occurred on October 2,
| delaying its release because of operational security concerns.
| China has capitalized on that delay, suggesting it is
| suspicious."
|
| Public notice within 5 days isn't too bad given we are talking
| about a strategic asset.
| WillPostForFood wrote:
| Yes, you are right, especially under normal circumstances. In
| this case it allowed a window for China to take advantage of
| the delay in releasing the information and use it for their
| own PR spin.
| shanxS wrote:
| I wonder how did this really happen? I mean, mountains don't
| move, at least not the the timescale of a submarine's motion: 1.
| Don't submarine use some form of radars to figure what's around
| then and where are they headed? 2. Assuming there were radars,
| were there no alarms or were the alarms ignored?
| kevinsundar wrote:
| Submarines often don't use active sonar as that sonar could
| give away the presence and location of the submarine.
| [deleted]
| dragonwriter wrote:
| > Don't submarine use some form of radars to figure what's
| around then and where are they headed?
|
| No. Radar is basically useless under water (many submarines do
| have surface search radar available, but that wouldn't help),
| and while they have _sonar_ it breaks stealth and is usually
| used tactically, and with a very specific cause, not as a
| continuous interrogation of the environment.
| jandrese wrote:
| Also active sonar deafens nearby sea life. Running around
| with it on constantly would be an ecological harm.
| trynumber9 wrote:
| It is pretty easy to run into a sea mount when active sonar
| isn't on. All it takes is misinterpreting a chart or an
| inaccurate chart.
| sulam wrote:
| There are several circumstances where submarines don't actually
| use their sonar. They have it, but a submarine that is pinging
| is easily identified / tracked.
|
| The underlying question is why they were in an area that hadn't
| been adequately mapped.
| dylan604 wrote:
| When evading, sometimes you have to leave the safe zone.
| OpFor will probably be familiar with safe operating areas and
| limit search zones. Would a USS Captain risk the boat by
| leaving uncharted areas to avoid detection? Just an idea of
| why.
| giantrobot wrote:
| > Don't submarine use some form of radars to figure what's
| around then and where are they headed?
|
| No. When submerged they rely on navigation charts (with higher
| than normal bathymetric details), passive sonar, and their
| navigation instruments. A submerged submarine blasting out
| active radar and sonar to determine its position wouldn't be
| very stealthy.
|
| Not every part of every ocean has complete bathymetric details.
| Seamounts don't necessarily move but undersea volcanos can grow
| in size significantly in short periods of time. A change in a
| few meters height can make last year's chart inaccurate today.
| wil421 wrote:
| Just to add to what others said. If a submarines uses its sonar
| enemies can hear it. They can also save the subs unique
| signature and then use it later to identify it. You don't want
| an enemy to know where and who you are.
| ckastner wrote:
| 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
| pdonis wrote:
| _> 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.)
| jacquesm wrote:
| Inconceivable. And I do know what that word means.
| mediaman wrote:
| 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.
| rjsw wrote:
| 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.
| CalChris wrote:
| 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.
| TeMPOraL wrote:
| It's not the mass difference that matters, but how rapid a
| momentum transfer your structure can survive.
| heartbreak wrote:
| You have underestimated the weight of a loaded cargo
| container by more than 50%.
| jacquesm wrote:
| 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.
| oivey wrote:
| As anyone who has hit a deer in their car can tell you,
| that's not how momentum works.
| CalChris wrote:
| 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.
| oivey wrote:
| 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.
| jacquesm wrote:
| 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.
| latchkey wrote:
| 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.
| oivey wrote:
| 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.
| costigan wrote:
| 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.
| nielsbot wrote:
| 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...
| laurent92 wrote:
| 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.
| ashtonkem wrote:
| Detecting echoes requires that they're running active sonar,
| which announces their presence to everyone and somewhat ruins
| the raison d'etre for submarines. Running passive they can
| detect surface ships, but not mountains per se.
| jdavis703 wrote:
| 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.
| krisoft wrote:
| > 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.
| oivey wrote:
| 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.
| Multicomp wrote:
| 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.
| frosted-flakes wrote:
| Why bother even going anywhere? It's a sealed box without
| windows--who'd know the difference?
| imdsm wrote:
| can we have some port holes?
| paul_f wrote:
| Would it be unusual for a sub to be traveling in a poorly mapped
| area? Seems they would only follow well known trusted underwater
| pathways
| wolverine876 wrote:
| The mountain is in the South China Sea, a leading focus of the US
| Navy. We learn something about the state of underwater mapping
| from the fact that even in the South China Sea a mountain wasn't
| mapped.
|
| Why can't satellites map the topology using something like RADAR
| (though likely using other frequencies), which I believe is done
| on land? Is there no technology that will penetrate water
| sufficiently? Is it a physical limit of electromagnetic energy
| and water?
|
| I assume it hasn't been done by satellite because otherwise we
| wouldn't have unmapped mountains, and because the same technology
| could help find submarines, taking away their stealth and
| eliminating a nuclear deterrent.
| fghorow wrote:
| Civilian geophysicist (but not an oceanographic one) here. This
| is my best understanding:
|
| As others have posted, above surface based propagating EM
| techniques won't work because seawater is conductive.
|
| Acoustic waves are probably the best way to map bathymetry, but
| that requires active sonar. The subs don't use that because it
| gives away their position. Surface mapping (sidescan sonar) in
| the area is probably the best viable technique to do the job,
| but geopolitical concerns make it impractical.
|
| Aside from sonar, gravity and magnetostatics could in principle
| be used to find seamounts. But both suffer from a fundamental
| problem that "upward continuation" decays short wavelengths
| exponentially faster than long wavelengths. In other words, to
| horizontally resolve a seamount with a characteristic length of
| (say) 10km you'd need to fly no higher than 10km. That rules
| out satellites. What's left are airborne and surface based
| surveys, which face the same geopolitical issues as sidescan
| sonar.
|
| Give all of that, you might as well do the sonar survey, as
| long as you can solve the geopolitical problems.
| 01100011 wrote:
| > Why can't satellites map the topology using something like
| RADAR
|
| If you were close enough, say in a plane, you could do
| something to cause a soundwave to propagate through the water.
| Say you fire a femtosecond laser pulse or blast it with an
| ultrasonic pulse. You could then, probably, use a second laser
| to pick up the reflections as disturbances on the surface.
| Otherwise you're probably stuck, since RF doesn't propagate
| well through a conductive fluid. Submarines can communicate
| somewhat using very, very low frequencies of electromagnetic
| energy, but the problem with that is the resolution at those
| wavelengths would be very, very poor.
|
| The best bet at this point in time is probably to just make a
| bio-mimicing, underwater drone and map under the surface. If
| you were really clever, you'd just hook some electrodes into a
| whale's brain and make it carry your mapping payload, using
| whale sounds to map the ocean floor. Not very nice thing to do
| to a living creature, but we've done very bad things in the
| name of national security before.
| numpad0 wrote:
| I think it's not just possible but done[1], I do wonder why it
| still happened though. Maybe maps were outdated or resolution
| is not ideal?
|
| 1:
| https://www.esa.int/ESA_Multimedia/Images/2012/05/Mapping_th...
| fghorow wrote:
| That radar is actually measuring the sea height. Sea height
| (on average) more-or-less defines the geoid (the height of an
| equipotential surface) over the oceans. That ignores sea
| height disturbances due to winds, currents, tides, etc. The
| geoid, in turn, is sensitive to local mass distributions. So
| yes, "it has been done", but the result is nowhere near the
| resolution or interpretability of a sonar survey. Still, it
| would greatly surprise me if the military _wasn't_ already
| using the technique. So, if there were interpretable results
| from the technique, I would personally expect the Navy
| already had them...
| woeirua wrote:
| Radar does not penetrate through brine water. Other remote
| sensing techniques have such poor resolution that they are
| relatively useless for this task. Unfortunately, sonar based
| bathymetry is really the best tool for this task and that means
| you have to run around with a surface ship mapping out the sea.
| As you can imagine the Chinese are not a big fan of American
| ships doing that in waters that they claim to be theirs.
| stickfigure wrote:
| > As you can imagine the Chinese are not a big fan of
| American ships doing that in waters that they claim to be
| theirs.
|
| Why does anyone (besides China) care? Nobody in that region
| recognizes those claims.
| wolverine876 wrote:
| > sonar based bathymetry is really the best tool for this
| task and that means you have to run around with a surface
| ship
|
| Why can't it be done from a plane or satellite? I can imagine
| answers (e.g., sound doesn't travel as well through air), but
| does anyone know?
|
| > the Chinese are not a big fan of American ships doing that
| in waters that they claim to be theirs
|
| I'd be surprised if that stopped the US in this circumstance.
| They regularly conduct operations in the South China Sea.
| simonh wrote:
| The kind of sensors you can put on a plane or satellite
| simply can't penetrate seawater effectively. It absorbs
| radar, dissipates heat and light. Sonar sound waves in air
| mostly just bounce off the ocean surface.
|
| This is why submarines are so stealthy and therefore
| militarily useful. As long as they stay quiet they're
| almost impossible to detect without using relatively short
| range active sonar.
| nradov wrote:
| The air / water interface makes it impossible to get any
| useful sonar data from an aircraft. Some military
| helicopters carry dipping sonar that they can temporarily
| lower into the water, and specialized aircraft can also
| drop sonar buoys, but those are designed for detecting
| submarines and are mostly useless for bathymetry.
|
| The US Navy does regularly operate in the South China Sea.
| In fact the USNS Mary Spears oceanography research vessel
| was there recently, presumably gathering bathymetry and
| other data.
|
| https://www.marinevesseltraffic.com/vessels/USNS-Mary-
| Sears-...
| wolverine876 wrote:
| Thanks.
|
| (I'd upvote you but for some reason votes don't stick, on
| comments and stories: When I reload the page, the arrows
| return, as if I hadn't voted. flag/vouch behaves
| normally. Perhaps a mod will read this.)
| roywiggins wrote:
| Sound doesn't transmit well at all between air and water in
| either direction. It just bounces off. You can't hear
| what's going on underwater when you're out of the water and
| you can't hear what's going on above water when you're
| underwater.
| nitrogen wrote:
| How do anti-glare coatings on lenses work? Could
| something similar be devised for the air-water interface?
| stickfigure wrote:
| Sure. You just need to apply your anti-glare coating to
| the world's oceans.
| zitterbewegung wrote:
| Water isn't air? Even air can become opaque.
| woeirua wrote:
| Sound doesn't travel as well through the air, but it still
| does. The primary reason that you can't do it from the air
| is that the surface of the ocean is a big irregular
| reflector of acoustic energy from the air, so the
| overwhelming majority of the energy will be lost. It just
| would never be practical.
|
| It might be possible to use airborne gravity gradiometry to
| map seaborne mounts. I'd never considered that before, but
| I see no reason to think it wouldn't work.
| willis936 wrote:
| Yes, water is a very excellent RF attenuator at all
| frequencies. Acoustic waves travel quite far in water,
| especially in the ~1 kHz range. Making loud sounds isn't
| something you want to do when you're somewhere you're not
| supposed to be though. If a mountain isn't making any noise
| then it's going to be difficult to know that it's there.
| nradov wrote:
| Electromagnetic energy doesn't penetrate water, at least not
| enough of the right wavelengths to be useful for mapping. The
| US Navy and NOAA do sea floor mapping using sonar. But it's a
| big ocean and some areas haven't been covered very well.
| jacquesm wrote:
| A good reminder that we know less about what's happening under
| the surface of the ocean than we do about LEO and near space.
| ChuckMcM wrote:
| I always wonder if the whales laugh at submarines for swimming
| around blind (not using active sonar).
|
| One of the more interesting thing over the last 10 years that
| I've been reading about has been the amazing amount of volcanic
| activity that is ongoing under the oceans. Not as photographic as
| crushing a community on an island, none the less mountains are
| growing out of the ground at an astonishing pace under the sea.
| skunkworker wrote:
| More info
|
| https://www.thedrive.com/the-war-zone/42954/uss-connecticut-...
| stevespang wrote:
| Cavemen would be able to conclude that the safe way to navigate
| through uncharted territory without sonar is the have a mini
| submersible drone out in front via cable (if needed) to make
| contact first and relay a DEAD STOP alert to the sub behind it.
| dirtyid wrote:
| Are there GIS / mapping software where you can fly through sea
| mounts with water off? Maps of ocean floor would be amazing to
| explore in MS flight simulator.
|
| http://onemanz.com/wp-content/uploads/2016/03/ocean_floor_ma...
| gnarlysasquatch wrote:
| Aren't there maps?
| [deleted]
| pugworthy wrote:
| Only where you go and record data to create said maps.
|
| Sonar systems have not mapped the entire sea floor, and as
| others have pointed out, sonar is the main effective way to
| create such a map.
| alfalfasprout wrote:
| and running sonar in enemy waters is not exactly a good idea
| :)
| pugworthy wrote:
| True, though they are very important for continued and safe
| commerce in said waters. If you have any kind of ship-based
| commerce passing through waters, you want good charted
| data, and you want that data made public for the safety of
| ships coming and going.
|
| It's worth pointing out that regular, non-military ships do
| run into uncharted seamounts too. A good example is the
| discovery of the Muirfield Seamount, which happened when a
| ship in what charts said was water over 5000 meters deep
| ran into it. The top was only 16-18 meters below the
| surface.
|
| See https://en.wikipedia.org/wiki/Muirfield_Seamount
| brokenmachine wrote:
| Well, now the map of that area has one mountain on it.
| [deleted]
| teedotem wrote:
| Reminds me of this urban legend story:
|
| This is the transcript of a radio conversation of a US naval ship
| with Canadian authorities off the coast of Newfoundland in
| October, 1995. Radio conversation released by the Chief of Naval
| Operations 10-10-95.
|
| Americans: Please divert your course 15 degrees to the North to
| avoid a collision.
|
| Canadians: Recommend you divert YOUR course 15 degrees to the
| South to avoid a collision.
|
| Americans: This is the Captain of a US Navy ship. I say again,
| divert YOUR course.
|
| Canadians: No. I say again, you divert YOUR course.
|
| Americans: This is the aircraft carrier USS Lincoln, the second
| largest ship in the United States' Atlantic fleet. We are
| accompanied by three destroyers, three cruisers and numerous
| support vessels. I demand that YOU change your course 15 degrees
| north, that's one five degrees north, or countermeasures will be
| undertaken to ensure the safety of this ship.
|
| Canadians: This is a lighthouse. Your call
|
| Copied from here:
|
| https://en.wikipedia.org/wiki/Lighthouse_and_naval_vessel_ur...
| [deleted]
| heavenlyblue wrote:
| It is funny, but isn't it kind of a maritime rule or law that a
| smaller vessel always gives way to a larger one? So it makes
| sense they would say that really.
| AlexAndScripts wrote:
| There is a variation of this for every nationality of
| lighthouse under the sun.
|
| It's still quite funny though.
| ineedasername wrote:
| Not a bad lesson to keep in mind in life: sometimes you're a
| lighthouse that has to deal with a ship, which is frustrating.
| And sometimes you're the ship, and you should learn from those
| mistakes.
| mig39 wrote:
| lol! Great urban legend, you're right. I remember hearing it
| back in the 90s!
|
| https://www.snopes.com/fact-check/the-obstinate-lighthouse/
| TheAceOfHearts wrote:
| I don't know if it's fake, but I've heard this clip and the
| encounter is with Spain:
| https://www.youtube.com/watch?v=xkx0MxK-Yl4
| hcrisp wrote:
| Similarly dramatized in this video:
|
| https://youtu.be/ajq8eag4Mvc
| pugworthy wrote:
| A different commenter mentioned airborne gravity gradiometry to
| map seaborne mounts. It definitely would work up to a point. It
| would tell you "there is more mass here", but there are different
| ways to interpret that information. A gravimetric map is not a
| map of land contours, but of the density of the geologic column
| below.
|
| That said, nearby masses (not below the sensor) also can
| influence the results. When doing gravimetric surveys on land,
| nearby buildings can have sufficient mass to influence the
| readings, so certainly a nearby seamount would also influence
| readings.
|
| Theoretically, a gravimiter inside of a submarine could be used
| to detect nearby masses. Which might or might not be a seamount
| you're about to run into. It would be like having automatic
| collision brakes on a car that could be misinterpreted based on
| ambiguous interpretation of sensor data. You'd want to get it
| right.
|
| For some background reading, I found this short write-up online
| about interpretation of gravity data ->
| https://sites.ualberta.ca/~unsworth/UA-classes/224/notes224/...
| suyash wrote:
| This is hard to believe, what really did they hit or what hit
| them in that region is anyone's guess now.
___________________________________________________________________
(page generated 2021-11-02 23:00 UTC)