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In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

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Re: In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

#81

Post by redis_mlc »

hinkley wrote: post #13
baobabKoodaa wrote: post #6

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 co…

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 pa…

> Sounds like the FAA altitude problem all over again.

It's not an altitude (alimeter) issue, it's a bearing (GPS airway) navigation issue.

With GPS, two airplanes can collide while on the centerline of the same airway at the same altitude, going in either direction, since GPS is accurate to about a foot.

Re: In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

#82

Post by jjk166 »

daveslash wrote: post #70

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…

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.

Re: In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

#83

Post by ARandomerDude »

daveslash wrote: post #70

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…

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.

Re: In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

#84

Post by nradov »

wil421 wrote: post #69
nradov wrote: post #66

Earlier quoted context omitted.

That's simply not how it works. The active sonar on your kayak has nowhere near enough power or resolution to detect a military submarine at sufficient range for reliable collision avoidance. Due to the inverse square law, active sonars have to put out a huge amount of power to detect submarines at any useful range. This is a proven risk to marine life. https://www.frontiersin.org/articles/10.3389/fmars.2017.0029...

The escort ships would know exactly where the sub they are escorting is. They could easy see the bottom or a massive blob passing underneath (an unknown sub) or even an undersea mountain. You don’t need enough resolution to tell if it’s a sub or even a whale you just need enough to say watch out. My middle of the road Garmin can see 1,100 feet deep in salt and side scan 500 feet in either direction. You can see botto…

You're really missing the point. No navy would ever assign one of their limited number of surface warships to that mission. There aren't enough to go around. And if a ship detects a massive blob passing underneath it's already too late. 1,100 feet isn't nearly enough range for collision avoidance; a ballistic missile submarine can't turn on a dime and a collision risk can come from any direction including astern. None of your suggestions are even remotely practical in the real world.

When submarines actually need to be sure of avoiding collisions they just run on the surface and follow the same rules of the road as any other vessel.

Re: In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

#85

Post by jrockway »

etimberg wrote: post #40
yummypaint wrote: post #24

Earlier quoted context omitted.

These days there are special collision avoidance systems on big commercial planes: TCAS II provides the pilot with specific instructions on how to avoid the conflict with traffic. These instructions are known as a “Resolution Advisory” (RA) and may instruct the pilot to descend, climb, or adjust vertical speed. TCAS II systems are also able to communicate with each other to ensure that the RA provided to each aircraf…

I believe TCAS is built off of ADS-B which is terribly insecure https://youtu.be/CXv1j3GbgLk

TCAS isn't built off of ADS-B (it existed long before ADS-B was ever conceived), but it's the same basic idea (mode c / mode s transponders) and probably has the same theoretical security vulnerabilities.

There's a pilot at the controls so that the technology doesn't have to be perfectly secure.

If you want to walk around broadcasting fake ADS-B or Mode C signals, someone will probably find you in hours, and the only effect it will have is maybe reducing the throughput of the busiest airports if the weather happens to be particularly marginal that day.

Re: In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

#86

Post by NickNameNick »

trhway wrote: post #71
baobabKoodaa wrote: post #6

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 co…

USSR concept of naval bastions 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.

Clearly with limited success -

That article links to https://en.wikipedia.org/wiki/Submarine_incident_off_Kola_Pe...

Which in turn links to https://en.wikipedia.org/wiki/Submarine_incident_off_Kildin_...

So there have been at least two other submarine collisions.

Re: In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

#87

Post by bell-cot »

nradov wrote: post #84
wil421 wrote: post #69

Earlier quoted context omitted.

The escort ships would know exactly where the sub they are escorting is. They could easy see the bottom or a massive blob passing underneath (an unknown sub) or even an undersea mountain. You don’t need enough resolution to tell if it’s a sub or even a whale you just need enough to say watch out. My middle of the road Garmin can see 1,100 feet deep in salt and side scan 500 feet in either direction. You can see botto…

You're really missing the point. No navy would ever assign one of their limited number of surface warships to that mission. There aren't enough to go around. And if a ship detects a massive blob passing underneath it's already too late. 1,100 feet isn't nearly enough range for collision avoidance; a ballistic missile submarine can't turn on a dime and a collision risk can come from any direction including astern. Non…

I suspect that wil421's idea is that the "near-harbor escort" job does not need anything near so grand as a surface warship. A low-end tugboat or similar would more than suffice.

Re: In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

#88

Post by imwillofficial »

wil421 wrote: post #69
nradov wrote: post #66

Earlier quoted context omitted.

That's simply not how it works. The active sonar on your kayak has nowhere near enough power or resolution to detect a military submarine at sufficient range for reliable collision avoidance. Due to the inverse square law, active sonars have to put out a huge amount of power to detect submarines at any useful range. This is a proven risk to marine life. https://www.frontiersin.org/articles/10.3389/fmars.2017.0029...

The escort ships would know exactly where the sub they are escorting is. They could easy see the bottom or a massive blob passing underneath (an unknown sub) or even an undersea mountain. You don’t need enough resolution to tell if it’s a sub or even a whale you just need enough to say watch out. My middle of the road Garmin can see 1,100 feet deep in salt and side scan 500 feet in either direction. You can see botto…

No the escort ships do not know exactly where the sub is.

On my first submarine duty, we nearly surfaced right in the path of our escort. We had to dive hard to avoid getting run over. “Clearing baffles” is not an exact science.

Re: In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

#89

Post by imwillofficial »

nradov wrote: post #84
wil421 wrote: post #69

Earlier quoted context omitted.

The escort ships would know exactly where the sub they are escorting is. They could easy see the bottom or a massive blob passing underneath (an unknown sub) or even an undersea mountain. You don’t need enough resolution to tell if it’s a sub or even a whale you just need enough to say watch out. My middle of the road Garmin can see 1,100 feet deep in salt and side scan 500 feet in either direction. You can see botto…

You're really missing the point. No navy would ever assign one of their limited number of surface warships to that mission. There aren't enough to go around. And if a ship detects a massive blob passing underneath it's already too late. 1,100 feet isn't nearly enough range for collision avoidance; a ballistic missile submarine can't turn on a dime and a collision risk can come from any direction including astern. Non…

Surface ships often escort subs in dangerous waters.

Ref: Dolphin wearing submariner.

Edit: Removed extraneous statements.

Re: In 2009, Two Nuclear Submarines Collided Under the Sea (2016)

#90

Post by imwillofficial »

addingnumbers wrote: post #59
gpm wrote: post #57

Earlier quoted context omitted.

But there is an appreciable difference between "if you can hear them, they've already found you", and "if you can hear them, they might never find you because you can see them looking from farther away than they can see, and they might just be outright searching the wrong area". All my arguments went to the latter kind of problem, not the former. Your 40 seconds number seems to be based on the speed of signal propaga…

I see where you're coming from. Good points. I was taking it for granted that knowing the location of an unmanned, expendable sonar buoy or probe before you're discovered is not tactically important. Now that you have me thinking, it would clearly allow you to stay out of detection range if you had the good fortune for their pings to initiate within your detection range but outside theirs.

Not only your own detection range, but those of other vessels and listening stations that are aligned with you.
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