In 2009, Two Nuclear Submarines Collided Under the Sea (2016) • Hacker News Board

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

#21

Post by SonicScrub » Mon, Aug 30, 2021, 3:51 PM UTC

uga4012 wrote: post #3

Are they really not detectable from space?

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.

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

#22

Post by jazzyjackson » Mon, Aug 30, 2021, 3:54 PM UTC

uga4012 wrote: post #3

Are they really not detectable 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

[0] http://hyperphysics.phy-astr.gsu.edu/hbase/Chemical/watabs.h...

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

#23

Post by zoomablemind » Mon, Aug 30, 2021, 3:56 PM UTC

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?

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

#24

Post by yummypaint » Mon, Aug 30, 2021, 3:56 PM UTC

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…

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 aircraft maximizes separation.

From https://nbaa.org/aircraft-operations/communications-navigati...

My understanding is these automated instructions override those from ATC

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

#25

Post by omni » Mon, Aug 30, 2021, 3:58 PM UTC

earthbee wrote: post #14

feral wrote: post #12

Earlier quoted context omitted.

Because it could be active?

Then you could hear them coming and avoid them

If you can hear them, they've already found you

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

#26

Post by NovemberWhiskey » Mon, Aug 30, 2021, 4:00 PM UTC

changoplatanero wrote: post #20

jaywalk wrote: post #4

Earlier quoted context omitted.

Why do you think they would be detectable from space? That doesn't make any sense.

There is a technique for finding nuclear submarines from space by using satellites to look for the hot water exhaust from the nuclear reactors.

Let me get this straight - there's a technique for detecting changes in the surface temperature of the water from a submarine that's probably hundreds of meters below the surface?

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

#27

Post by tjohns » Mon, Aug 30, 2021, 4:02 PM UTC

zoomablemind wrote: post #23

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.

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

#28

Post by sca4 » Mon, Aug 30, 2021, 4:03 PM UTC

uga4012 wrote: post #3

Are they really not detectable from space?

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...

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

#29

Post by gpm » Mon, Aug 30, 2021, 4:05 PM UTC

omni wrote: post #25

earthbee wrote: post #14

Earlier quoted context omitted.

Then you could hear them coming and avoid them

If you can hear them, they've already found you

Surely not.

The submarine with the larger more sensitive instruments in a quieter environment ought to be able to detect sound levels below that which their active opposition can.

If X amount of noise-energy hits the submarine, it only reflects YBoth of these weigh in favor of the submarine detecting the searcher before the searcher detects the submarine.

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

#30

Post by nradov » Mon, Aug 30, 2021, 4:10 PM UTC

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…

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.