One really fascinating aspect of sonar that leads to risks/collisions like this, is that there are ‘blind spots’ in the ocean. Because sound waves pass differently through water of different temperature and salinity and both of those change on gradients in the ocean, there are mathematical solutions to where a sub would be totally undetectable given a ship’s position and radar frequency. Because these locations are obviously useful for subs, two+ can sometimes end up in the same warm pocket, which obviously increases collision chances from a naive hundred-cubed-km search space
So the submarines can't use active sonar, because their number one priority is to avoid detection... but then these subs are all parked in the same "parking spots" in the ocean. If the favored parking spots for submarines are so rare and small that collisions happen more than once, surely that undermines their stated number one priority of remaining hidden? If someone wanted to locate enemy submarines, surely they could just send a bunch of underwater drones to swim through these parking spots?
There are no parking spots. Ballistic missile submarines conducting deterrence patrols are assigned to large areas covering hundreds of square nautical miles. The sub then maneuvers inside that patrol area to remain as hidden as possible. They almost never stop as it's easier to maintain depth control with at least a few knots of steerageway. So a collision in open ocean is theoretically possible but highly unlikely.
The real risk of collisions comes with transiting through constricted navigational channels, typically when leaving or entering port. Those channels force a lot of vessels into a small area. There have also been a few incidents where submarines failed to do a thorough surface search before surfacing and collided with smaller boats.
During the Cold War there were supposedly a few incidents where NATO attack submarines were following Soviet submarines too closely and ended up colliding.
Sounds like the FAA altitude problem all over again.
As altimeters got more accurate, the odds that you were flying at exactly 28000 feet went up. If an air traffic controller fucks up and puts two planes at 28000ft, they can now collide because they're ±10ft instead of ±200ft. That was the RCA of that mid-air collision over Brazil a while back.
The more you try to control a thing the more problems you can have. A parking lot for stealth ships is... I don't want to say dumb but confusing for sure.
You don’t need drones. Planes and helicopters already drop sonar buoys for the exact reason you stated.
A better solution would be for an escort when they get into crowded lanes. Surface ships can use active sonar to scan for other subs while being some what close to their sub. The only problem is other listeners can pick up on what is reflecting off your active sonar as well. Also the subs try to avoid ever being detected because they can save your signature for comparison later.
How are the drones going to detect them apart from randomly running into them? Simpler approach is for an adversary to just cruise attack boats through these areas, which you would want to do anyway since once you detect them you want to sink them in wartime.
If the passive sonar filling the entire nose of a huge submarine can't hear another submarine, why would a much smaller sonar in the nose of a drone be able to detect a submarine?
Re >> "the French Ministry of Defense reported that the submarine had suffered a collision with an “an immersed object (probably a container).”"
and
Re >> "At some point, the two navies compared notes"
I get that ballistic submarines want to stay secret and use passive sonar, instead of active sonar. But I also would have thought - if a submarine mysteriously ran into something under water that they did not expect to be there, that they'd start taking a more "active" approach to figuring out what was going on. It'd be like if I tried to walk blindfolded through a large & empty conference room: if I bumped into a whole wall after walking only 3 or 4 steps, I'd be very confused!
The trouble is whom and how to ask. The submarine world is a giant, international cat and mouse game, and asking around gives away operational details that may involve compromising other things (e.g., special operations deployments) if you say "at exactly X coordinates at time T we bumped into something. Anybody know?"
Also, since the dawn of militaries, much of what occurs is posturing. You want the other side to think you are big, bad, competent professionals. "We ran into something and we don't know what" makes you less superhuman in the eyes of the public and potential adversaries.
It sounds like both subs took damage around their sonar systems, so it's possible they couldn't use active sonar after the collision even if they wanted to.
Surprisingly, no side was assigned the blame for the collision. Unlike air traffic or surface navy accident.
One had a conning tower damage, the other had a bow damage; both were supposedly slow-moving at the moment. Is there such thing as right of way for subs?
How do you exercise right of way over another submarine that you don't know the position of?
The whole point of submarines is that they're stealthy. Active sonor would give away their position. They're basically swimming blind. The only way this all works is the ocean is big enough that random collisions are statistically rare - but there's not much actually preventing them.
No right of way, but there are movements called “baffle clearing” where you check your blind spots before moving.
Due to the fickle nature of the mistress that is the ocean, sometimes even properly executed movements can still be dangerous.
each carrying 4 and 6 nuclear warheads respectively. Losing such apocalyptic firepower on the ocean floor would have been a catastrophe. However, nuclear warheads are not susceptible to “going off” as a result of a collision.
What is the catastrophe if this had happened? The weapons won't explode. Is it the danger that they'll leak their radioactive fuel, or that they'll be captured by some enemy power before they can be retrieved (if they can be retrieved at all)?
Pie in the sky ideas here... but how far is active sonar effective for? Can you launch a probe that enables active sonar some 50-100 miles away, and radios the results back? Or would the depth prevent any type of radio communication...or is active sonar not that long-range?
This whole field is really fascinating to think about.
The effective range of active sonar varies tremendously based on many factors: power output, microphone sensitivity, signal processing, bottom contour, water temperature, ambient noise, etc. There is no typical range. Aircraft can drop active sonobuoys but they're very expensive and in limited supply. Use of active sonar is restricted in many areas due to impact on marine life.
Water blocks all radio traffic except for extremely low frequency. The bandwidth on that is too low to use as an effective navigation aid, and transmissions can only be sent from large facilities on land. Some submarines can also send up floating antennas on towed buoys but they prefer not to do so due to the risks of detection and entanglement.
Even more amazing, only a month later (or before) two satellites collided in LEO. Literally astronomical odds, and the two incidents happened so soon after one another as well.
Lot of dismissive reactions to these questions, but there actually are non sound related signals we use to detect submarines and there is absolutely research on how to do that from space.
This article is great, but just read the "Signal Processing" section if you're interested in space.
https://www.aspistrategist.org.au/prospects-for-game-changer...
Not sure if they are, but I do know that the US Navy funded a lot of oceanographic research into predicting and understanding bioluminescence of marine organisms for this very reason. The surface waters of the North Atlantic have massive spring blooms of phytoplankton, which are sometimes bioluminescent, and could certainly give away the presence of a large subsurface vessel, possibly from space.
next time you're out on the open ocean check how far down into the water you can see, and then check out this graph [0] of electromagnetic radiation absorption of water: visible light is the best case scenario.
there's a reason sonar is acoustic and not light based
This is fairly open secrets to the degree that it is secret at all so it probably also is no big secret that passive and active countermeasures are used to prevent these techniques.
The US Navy has researched the possibility of detecting shallow submarines from space since at least the 1990s by looking for subtle wake turbulence on the surface. The results are classified so we don't know if they were ever successful. It's not completely impossible, but the signal to noise ratio would be extremely low.
Any detection from space would have to use an optics system to detect light bouncing off the submarine. This light could be either the naturally occurring visible light, or some form of active system (probably emitting radar waves).
Unfortunately light can't penetrate very far into water, so this idea is a non-starter. Light can barely make it 200m into the ocean (meaning 100m depth for light to make a round-trip and back for detection), and subs can go as deep as 300m.
Any satellite-based detection system would have to rely on catching the sub while on the surface. I'm positive this is being attempted constantly, but catching a sub at depth is an entirely different manner.
Using what technology? I can imagine in some future there being the means, but I find it hard to believe we have that level of tech available to the sort of packages we can aloft into orbit now.
Subs would be detectable using magnetometers, except that they have electromagnets in them to hide their magnetometer footprint. Still, this is not perfect.
Large subs have somewhat detectable gravitometric footprints that could be observed from space, indeed.
[+] [-] Galxeagle|4 years ago|reply
https://m.youtube.com/watch?v=AqqaYs7LjlM
[+] [-] baobabKoodaa|4 years ago|reply
[+] [-] nradov|4 years ago|reply
The real risk of collisions comes with transiting through constricted navigational channels, typically when leaving or entering port. Those channels force a lot of vessels into a small area. There have also been a few incidents where submarines failed to do a thorough surface search before surfacing and collided with smaller boats.
During the Cold War there were supposedly a few incidents where NATO attack submarines were following Soviet submarines too closely and ended up colliding.
[+] [-] hinkley|4 years ago|reply
As altimeters got more accurate, the odds that you were flying at exactly 28000 feet went up. If an air traffic controller fucks up and puts two planes at 28000ft, they can now collide because they're ±10ft instead of ±200ft. That was the RCA of that mid-air collision over Brazil a while back.
The more you try to control a thing the more problems you can have. A parking lot for stealth ships is... I don't want to say dumb but confusing for sure.
[+] [-] wil421|4 years ago|reply
A better solution would be for an escort when they get into crowded lanes. Surface ships can use active sonar to scan for other subs while being some what close to their sub. The only problem is other listeners can pick up on what is reflecting off your active sonar as well. Also the subs try to avoid ever being detected because they can save your signature for comparison later.
[+] [-] trhway|4 years ago|reply
https://en.wikipedia.org/wiki/Bastion_(naval)
>If someone wanted to locate enemy submarines, surely they could just send a bunch of underwater drones to swim through these parking spots?
back then it were US attack submarines which USSR tried to actively track and push out of the bastions.
[+] [-] yborg|4 years ago|reply
[+] [-] earthbee|4 years ago|reply
[+] [-] daveslash|4 years ago|reply
and
Re >> "At some point, the two navies compared notes"
I get that ballistic submarines want to stay secret and use passive sonar, instead of active sonar. But I also would have thought - if a submarine mysteriously ran into something under water that they did not expect to be there, that they'd start taking a more "active" approach to figuring out what was going on. It'd be like if I tried to walk blindfolded through a large & empty conference room: if I bumped into a whole wall after walking only 3 or 4 steps, I'd be very confused!
[+] [-] ARandomerDude|4 years ago|reply
Also, since the dawn of militaries, much of what occurs is posturing. You want the other side to think you are big, bad, competent professionals. "We ran into something and we don't know what" makes you less superhuman in the eyes of the public and potential adversaries.
[+] [-] jjk166|4 years ago|reply
[+] [-] unknown|4 years ago|reply
[deleted]
[+] [-] codezero|4 years ago|reply
[+] [-] zoomablemind|4 years ago|reply
One had a conning tower damage, the other had a bow damage; both were supposedly slow-moving at the moment. Is there such thing as right of way for subs?
[+] [-] tjohns|4 years ago|reply
The whole point of submarines is that they're stealthy. Active sonor would give away their position. They're basically swimming blind. The only way this all works is the ocean is big enough that random collisions are statistically rare - but there's not much actually preventing them.
[+] [-] imwillofficial|4 years ago|reply
Submarine life is insanely dangerous.
[+] [-] juanani|4 years ago|reply
[deleted]
[+] [-] Johnny555|4 years ago|reply
What is the catastrophe if this had happened? The weapons won't explode. Is it the danger that they'll leak their radioactive fuel, or that they'll be captured by some enemy power before they can be retrieved (if they can be retrieved at all)?
[+] [-] clipradiowallet|4 years ago|reply
This whole field is really fascinating to think about.
[+] [-] nradov|4 years ago|reply
Water blocks all radio traffic except for extremely low frequency. The bandwidth on that is too low to use as an effective navigation aid, and transmissions can only be sent from large facilities on land. Some submarines can also send up floating antennas on towed buoys but they prefer not to do so due to the risks of detection and entanglement.
[+] [-] egberts1|4 years ago|reply
One could deploy low-power laser scanning as an anti-collision mechanism when venturing into narrow channels, no?
[+] [-] dotancohen|4 years ago|reply
[+] [-] FridayoLeary|4 years ago|reply
[+] [-] archsurface|4 years ago|reply
[+] [-] uga4012|4 years ago|reply
[+] [-] sca4|4 years ago|reply
[+] [-] lnwlebjel|4 years ago|reply
[+] [-] dmos62|4 years ago|reply
[+] [-] jazzyjackson|4 years ago|reply
there's a reason sonar is acoustic and not light based
[0] http://hyperphysics.phy-astr.gsu.edu/hbase/Chemical/watabs.h...
[+] [-] skinkestek|4 years ago|reply
This is fairly open secrets to the degree that it is secret at all so it probably also is no big secret that passive and active countermeasures are used to prevent these techniques.
[+] [-] nradov|4 years ago|reply
[+] [-] SonicScrub|4 years ago|reply
Any satellite-based detection system would have to rely on catching the sub while on the surface. I'm positive this is being attempted constantly, but catching a sub at depth is an entirely different manner.
[+] [-] detritus|4 years ago|reply
[+] [-] cryptonector|4 years ago|reply
Subs would be detectable using magnetometers, except that they have electromagnets in them to hide their magnetometer footprint. Still, this is not perfect.
Large subs have somewhat detectable gravitometric footprints that could be observed from space, indeed.
[+] [-] TeMPOraL|4 years ago|reply
[+] [-] jaywalk|4 years ago|reply