A question based on this story :
Is it really possible for subs, nuclear or not, to collide these days? I can understand that one of the sonar guys messing up but wouldn’t it take both sonar guys on each sub’ to mess up for this to happen?
Are there metrological condictions that would account for this?
Hey before you blame the sonar guys we need some more information.
The article doesn’t mention:
Were either or both the subs submerged?
If submerged were they operating together or independently?
If independently were they aware of the others’ operational proximity?
If either sub was surfaced, Officer of the Deck’s fault.
A training exercise that allows two subs to collide has poor parameters and operational control, officers again.
A series of circumstances that puts two NATO subs in the same piece of water without the knowledge of both crews is the fault of a lot of officers with much more rank than a sonar guy.
Rough seas mentioned in the article could make broadband detection of another sub difficult until the two were very close.
If sonar had any signs of a submerged contact and failed to recognize them, THEIR fault… and cardinal sin of sonar.
Point taken (I should have know better on the SDMB). I’ll see what I can dig up…
Both subs on separate exercises.
French Triomphant class
UK sub was submerged - French sonar dome damaged
The BBC article also mentions speculation that the subs’ anti-sonar detection units may have contributed to the accident.
Reminds me of when the (surfacing) US Navy sub hit a japanese fishing boat off hawaii.
The ocean is a big place-what are the chances of two subs colliding?
However, the naval code is harsh and unforgiving-both captains will be held responsile, and both will (most likely) be captaining a desk before retirement.
Nuclear subs rarely activate their active sonar systems, especially when on exercises during which they want to remain undetected. The sonar techs failure to detect each other is not a testimony to their lack of skill but to just how quiet nuclear subs are these days.
The Soviets for a time were trying to claim that the K219 accident was caused by a collision with the US attack sub Augusta. It probably wasn’t the case, but it was trailing closely enough for it to be plausible.
With the Russian navy resuming expanded patrols, especially into the Pacific, I wouldn’t doubt there’s occasional if not constant contact between US and Russian submarines in the open ocean. Seeing as how the idea of nuclear submarine operation is to remain undetected, collisions are always a possibility.
To reinforce that, at certain operational regime many modern submarines actually have a lower radiated acoustic signature than the surrounding ambient environment, i.e. they’re “a hole in the water,” quieter than the ocean they swim in. Submarines generally use passive acoustic systems to observe the environment around them, but this is equivalent to putting a blindfold on and walking around your house navigating by sound. Active sonar (colloquially referred to as a “Yankee search”) is rarely used by submarines except (and rarely) to precisely locate a known target because it makes an even bigger target of the boat that uses it, and in a tight littoral environment may actually make a lot of fake shadows from interference of reflected waves. Active sonar is primarily used by surface ships to intentionally harass or drive away enemy submarines, and by torpedoes to guide them to a final intercept solution.
The chance of impact between submerged vessels is one of the innate operating hazards. For this reason, submarines are usually given specific areas to patrol and are updated when other subs or navigation hazards are known to be in the area, but ultimately there is still a risk of collision. Batfish neatly sums up the responsibilities and likely proximate causes of a collision.
Stranger
The sea is a busy place, and when you get right down to it, most of the time, modern subs (and that most certainly included diesel-electric boats, too!) are routinely so quiet that such collisions are inevitable, despite the best procedures; Statistics will get you.
When you add in the limited sensor suites and limited visibility for (and of) submarines, well, what’s really impressive is the relative lack of such collisions.
Tranq,
Quailified in Submarines (enlisted)
From the original BBC News article, much expanded since this morning.
I hear all the time that modern submarines are extremely quiet in their operation. Quiet by what standard?
I know, this sounds simple, but that’s why I’m asking. If I were swimming a few hundred feet down in the ocean, (I know, bear with me), and able to do so without any gear on, and a modern nuke was coming up behind me, would I hear it?
Feel vibrations? In Red October, the Soviets start singing, and the guys on the Dallas can hear it through the sonar. Plausible?
NOTE: I’m guessing on my recollection of the movie.
Uh…wrong button. I meant for this to be a separate thread, and spelled correctly.
By “Quiet” they mean that modern boats (and that most certainly includes diesel boats!) are so quiet that the ocean makes more noise than the boat does.
Mechanical transients (think dropped wrench, slammed hatch, or torpedo fired) are a prime way to get detected. Singing… well, that’s unlikely to be heard at any realistic range unless the sonar conditions are exactly right. On the other hand, I have been woken by whalesong a couple times.
You would probably hear a low rumbling which would not be much or at all distinguishable from the ambient environment.
It would be virtually impossible to hear singing; most of the sound energy within the hull will be reflected (hence, why things echo so well in tunnels), and the anechoic coating on the outside of submarine hulls will dampen out most other normal sounds. The mechanical transients Tranquilis mentions are usually due to contact with some part of the hull or structure that attaches, which is transmitted directly to the water.
Stranger
I recall way back in a Navy ROTC summer cruise on a (Los Angeles Class attack) submarine (which had, IIRC, at most five days underway over the month I was there), that the sub was on exercises that required it getting “found” by another sub. So our skipper got the call, wired down to the auxiliary machine room (AMR) to get some noise made, and the petty officer in charge of the AMR (where I was “assigned” at the time) gave me a big wrench or something and showed me something to bang it against to make some noise and not hit anything important. I can’t say for certain that without such tactics we’d get into a collision, but it does seem that the other guys’ inability to find us was a serious obstacle.
And that was an attack sub. The boomers are even quieter, from what I can tell.
This very person was interviewed on NPR this afternoon. He said that there is control over where subs are, NATO subs, but since France is not under NATO command (though is coming back) the French sub might not have been in the system.
Ignorance fought! I WAS suffering under the delusion that France was part of NATO.
Hmmm… I suddenly have a craving for Freedom Fries.
I first heard that the subs were on seperate missions from an NPR report during the drive in to work yesterday. They also reported that boths subs were 500 feet in length and 200 feet in diameter.:smack:
[Yes Minister] And the puppy?
These are Stategic Missile Subs, “boomers”. Should’nt they be off sulking some where waiting for the order to go ballistic? Rather than operating in such close proximity?