You'd really have to wonder how this could happen after the 2005 incident when the USS San Francisco hit an uncharted seamount in the Pacific.
I claim no expertise in submarine navigation/collision avoidance but it seems to me that the something that went awry with the USS San Francisco might have happened again some 16 years later. Why weren't lessons learned?
I'd have thought that the detection of something as big as a seamount would have been child's play to a modern submarine and thus easily avoided. After all, detection of underwater objects is what submarines do - and one's enemy sub is a damned size smaller than a seamount.
What gives? Does anyone with sufficient declassified knowledge know how this could happen? Even if everyone was being inattentive or having lunch (as they were on the USS San Francisco) then why wouldn't sophisticated detection equipment warn well ahead of any potential accident happening?
I've been curious about this since that incident in 2005, now that it's happened again I'm even more so.
Lastly, do we really know the extent of uncharted seamounts? Silly, question being in the negative. Perhaps, rephrased the question should be how reliable are the charts/maps submarines use these days. (This could be just my lack of knowledge, but it seems subs may be blinder underwater than my perception of them has been until now.)
The vast majority of the time, boats don’t use active sonar. Whilst giving a high resolution view of what’s around them, it also allows any other signals collector (often defined as an enemy aggressor) to accurately pinpoint the location and deploy countermeasures, even if only updating threat assessments.
Ultra detailed charts are used that have the terrain mapped. Occasional positional fixes when a boat surfaces can be used to ‘reset’ where they thought they were whilst running silent.
"Occasional positional fixes when a boat surfaces can be used to ‘reset’ where they thought they were whilst running silent."
Yeah, fair enough that makes sense, but what I've read about modern underwater inertial navigation systems is their remarkable accuracy. You'd think that any selected course for the sub would be set well within the tolerance of the inertial navigation system thus the sub would steer well clear of any known seamount. Alternatively, it was uncharted and that brings me back to the accuracy of the maps.
P.S.: I'd also read somewhere that as part of the underwater navigation system that gravity detection was also used and it is sensitive enough to detect changes caused by massive nearby objects, seamounts etc. As they're passive detectors that wouldn't preclude them from being used all the time.
My boat has a $1000 piece of garmin equipment which will tell me exactly how far away the landmass under me is, and has another sonar angled forward which tells me a little bit about what's coming up.
It's possible that this type of sensing equipment isn't used when they are in hostile environments?
See my other posts - they should not have had to have had sonar on to detect the seamount. My question, is why did the two other alternatives not work (i.e.: inertial navigation and gravity detection)?
What do you keep talking about on this thread regarding gravity detection? Please link to a device that does that. Google only brings up gravity wave detectors.
How is inertial navigation supposed to work for an unmapped seamount? Sure that works for known seamounts but how’s that going to help around things that move due to tectonic plates or undersea volcanos? Or in unmapped or mis-mapped regions?
I cannot believe there's any argument about this. There are literally thousands of references. Below, are links to the first few references that I found.
Note: you'll see that in the first link in item #5 the comment about the strategic nature of this information, that means don't expect to get how-to-do-it plans from the military but you can bet your house to a brick that the military is deeply involved in gravity detection (specifically because, like inertial navigation, it's silent and doesn't broadcast its presence).
Also note the dates, this stuff goes back to even before the 1970s, the technology is now very mature.
The Garmin device they’re talking about is active sonar. That means it makes a big noise. It’s like shining a light into a dark room - everyone can see where the light is coming from.
In submarines active sonar is rarely if ever used. It will give you away instantly to anyone around you and then you give enemies your unique sonar signature. China and Russia could easily say Seawolf XXX is the South China Sea right now pinging around. This is SIGINT 101.
Submarines have the same radar and sonar we use for fishing when they are navigating public waterways and inlets. They do not use the military grade stuff in those situations.
The entire point of a submarine is that nobody knows it's there. If they are using easily detectable equipment then people who are listening know they are there.
As per my other post, seamounts can't hide their gravity signature. Remember, we've used gravity detection for many decades for mining as mineral deposits have a different density to other surroundings which means the differences in gravity can be detected.
And what I've read such detection is used as an adjunct to underwater inertial navigation systems. Perhaps, if it were not working or not installed then this accident may have exposed the fact and perhaps that's why senior offers were sacked. No doubt, we'll learn in time.
Inertial navigation means judging the vector you’ve moved on from a known position. It doesn’t help you detect anything out there unless you already knew it was there!
I don’t think we have perfected gravity sensors for use on submarines yet, so they would not have helped either.
A lot of people on this thread seem to be sort of thinking in their heads ‘why weren’t they looking out the windows?!’ Detecting things from submarines is very hard. At the moment you can basically only listen. And listening to something that doesn’t make any noise is a challenge!
I think these references aren't really about what you think they are.
Under #4, the first one is about navigation. Again, if you don't know somethings't there, then this doesn't help you. The second one is about detecting other submarines. This was an underwater mountain. The third one is about both things, which as we just said aren't applicable, and is also about a work of fiction.
The Google patent is, again, about an Inertial Navigation System. It says so in the first sentence. It doesn't do what we're talking about.
The final paper, if you read beyond the abstract, talks about it just being theoretically possible. (The title with the question mark is the clue!) So we don't know if the submarine has the technology or not, or how developed it is.
All that lets us know it isn’t ‘child play’. I think people are thinking of active sonar when they say that.
I don't know why you are going to such inordinate lengths to deny the obvious but that's your affair.
The facts are these and they are verifiable (based on unclassified public domain knowledge):
1. From various accounts, inertial navigation systems on modern submarines are phenomenally accurate and have been so since at least the 1970s. The absolute accuracy depends on (a) the initial calibration and the location of that calibration, (b) on the path or trajectory of the submarine (cumulative errors inherent in the inertial navigation system and charting errors, etc.) accumulated over the tour of duty; (c) unique/specific calibrations for certain operational requirements, locations etc. All this assumes the sub remains submerged and has no external calibration reference (but the fact that it remains submerged doesn't necessarily mean that it doesn't have the means to re-calibrate its inertial navigation—as it often does!).
2. The length of time a submarine can remain submerged and operate safely† on only its inertial navigation systems sans external calibration is usually classified but indications are that it can be months for nuclear submarines (again, much depends on operational requirements and the locations of those operations, the technical parameters of the inertial navigation, etc.).
† As discussed—excluding uncharted seamounts, etc. (whilst a rare event, we've now seen it happen twice within 16 years—the USS San Francisco being the first to collide with one).
3. However, the basic inertial navigation system is an open-loop system and thus subject to both long-term drift and long-term calibration imprecision—and other 'compensation' calibration stuff can only go so far in holding accuracy. Eventually, a submarine's inertial navigation system needs to re-calibrated. That said, in recent years, reports indicate newer inertial navigation technologies have led to even further substantial increases in open-loop accuracy. Obviously, the precision of this accuracy is classified.
4. Since the 1960s nuclear submarines have been able to communicate with the outside world whilst remaining submerged using VLF radio, https://en.wikipedia.org/wiki/Communication_with_submarines. Years ago, I used to take an interest in this and I could detect the RF carriers from the high power transmitters (≈1MW) used to communicate with submarines on ordinary radio equipment but obviously the modulated data they contained was meaningless to me. I've now only a brief public domain knowledge of how these days, say, the US uses this and associated newer communication technologies for calibration but you don't have to too bright to know that using atomic clocks you can triangulate a position with considerable accuracy (as per GPS). Using geopositioning in conjunction with gravity gradiometry, etc. cannot only act as a backup but it can also improve the 'local' location picture/accuracy.
5. "Under #4, the first one is about navigation. Again, if you don't know somethings't there, then this doesn't help you. The second one is about detecting other submarines. This was an underwater mountain."
I cannot understand why you cannot picture this. If you can detect another submarine by its small, somewhat reduced local gravity signature then you can also easily detect an unknown or uncharted seamount by its hugely increased local gravity signature (rock being denser than seawater and it being much larger than any enemy submarine is ever likely to be (ipso facto, as the sub's gravimetric detection equipment is capable of detecting a comparatively small submarine then it must also have a detection sensitivity many times more than is necessary to detect a huge seamount). Moreover, a submariner can use the very specific signature of a known seamount to re-calibrate his sub's inertial navigation system—as no two seamounts would ever have exactly the same gravimetric signature (and if by some billions-to-one chance they ever did, then they wouldn't be anywhere near each other to cause confusion).
For example, say a submarine has not surfaced for months and its captain has orders to fire a missile on date xyz. Whilst he knows pretty much where he is from the sub's inertial navigation system, its drift over the several months the sub's been at sea is not precise enough for him to determine the precise location needed to launch the missile (and the inertial navigation system of the missile also has to be calibrated/to be precise). He cannot surface for fear of being detected so what does he do to re-calibrate? Simple, he heads for a seamount (or some other underwater phenomenon) whose location and gravimetric signature has already been properly charted during some earlier survey, and he uses the sub's inertial navigations system to get him into the near vicinity of said seamount—as it's still accurate enough to do that with ease. Moreover, the sub won't collide with the seamount as its precise location is now clearly visible on the sub's gravimetric equipment. As he already knows the EXACT location of the seamount, he now has the perfect means to recalibrate the inertial navigation system. At no time has the sub surfaced, nor has it broadcast its position, as both of its underwater navigation systems are completely passive.
6. The links I provided were a first-pass effort, and sure, it's dead easy to nitpick them as you've done. The fact remains that all the references I've provided are relevant in that they all refer to various technologies that are integral to both submarine geopositioning and undersea collision avoidance. Separating them out is about as stupid as saying 'I'm going to build a computer but with only CPUs—RAM and monitors are off the menu, I won't be using them'.
7. "All that lets us know it isn’t ‘child play’." I beg to differ, when a technology has been in use for going on 50 years and has been through multiple stages of evolution of over this time to the extent that now commercial operators are using it on a day-to-day basis on their undersea ROVs etc., then essentially it is child's play to the big players such as DARPA, the Military and so on (however, that's not to say, there aren't any remaining difficulties). What we currently know from public domain sources is that this technology is already very sophisticated and it's not just theoretically possible, as it's working in practice and it has done so for decades. One would have to very stupid not assume that it's now much more so (given it's highly classified nature). Did you actually take the time to read this: https://en.wikipedia.org/wiki/Gravity_gradiometry ?
"Gravity gradiometers
Lockheed Martin gravity gradiometers
During the 1970s, as an executive in the US Dept. of Defense, John Brett initiated the development of the gravity gradiometer to support the Trident 2 system. A committee was commissioned to seek commercial applications for the Full Tensor Gradient (FTG) system that was developed by Bell Aerospace (later acquired by Lockheed Martin) and was being deployed on US Navy Ohio-class Trident submarines designed to aid covert navigation. As the Cold War came to a close, the US Navy released the classified technology and opened the door for full commercialization of the technology. The existence of the gravity gradiometer was famously exposed in the film The Hunt for Red October released in 1990."
8. I'm not responsible for why so many are still in WWII mode and are only thinking of [the limitations of] active sonar. Perhaps the Military has been smarter than I've given it credit for, in that it seems to have managed to keep an understanding of this technology even out of the eyes of many techies.
The obvious is they can't do this well... which is why they keep banging into them. The Americans, the British, we keep doing it.
Occam's Razor is the reason we keep bumping into mountains is that we aren't very good at detecting mountains.
People do genuinely seem to not be able to get their head around that it's harder than just looking out of a window, so it's good to remind them that it's state-of-the-art stuff to detect anything out there.
You may well be correct! If they're not capable of finding their position without surfacing for whatever reason then the whole nuclear deterrent is likely at stake (the missile's launch position being critical—or it used to be so).
I think nuclear deterrence runs patrols in very deep, very well-mapped areas that are planed well in advance, so are usually fine.
The issue is tactical manoeuvres in the South China Sea, where we don't know the terrain and we don't know where we'll need to go. In that environment all our tools are less effective (because we have less mapping, because sonar is not usable, because we're manoeuvring more so inertial navigation is less effective, because we're moving faster.)
I must admit I'd have thought that in the present circumstances that getting that right would have rated very high in strategic importance.
Moreover, given the high density of shipping in that section of the world from the earliest days (and especially so its strategic importance during the Cold War), I would have imagined that those waterways would have been the best documented/most accurately charted of anywhere.
As it always does, eventually the real reasons will leak out.
I claim no expertise in submarine navigation/collision avoidance but it seems to me that the something that went awry with the USS San Francisco might have happened again some 16 years later. Why weren't lessons learned?
I'd have thought that the detection of something as big as a seamount would have been child's play to a modern submarine and thus easily avoided. After all, detection of underwater objects is what submarines do - and one's enemy sub is a damned size smaller than a seamount.
What gives? Does anyone with sufficient declassified knowledge know how this could happen? Even if everyone was being inattentive or having lunch (as they were on the USS San Francisco) then why wouldn't sophisticated detection equipment warn well ahead of any potential accident happening?
I've been curious about this since that incident in 2005, now that it's happened again I'm even more so.
Lastly, do we really know the extent of uncharted seamounts? Silly, question being in the negative. Perhaps, rephrased the question should be how reliable are the charts/maps submarines use these days. (This could be just my lack of knowledge, but it seems subs may be blinder underwater than my perception of them has been until now.)