Nuclear Subs 'Collide In Ocean' 622
Jantastic noted a BBC report saying "A Royal Navy nuclear submarine was involved in a collision with a French nuclear sub in the middle of the Atlantic. It is understood HMS Vanguard and Le Triomphant were badly damaged in the crash earlier this month. Despite being equipped with sonar, it seems neither vessel spotted the other, the BBC's Caroline Wyatt said."
Odds ? (Score:5, Interesting)
Re:Whoops (Score:5, Interesting)
Nuclear submarines, and especially ballistic missile submarines, don't communicate with anyone at sea unless it's absolutely critical. Communicating gives away your position, and for such submarines, the fact that nobody outside the hull knows exactly where it is is their number one means of survivability. In addition, ballistic missile subs don't have 'allies' - they treat even the surface and submarine forces of their own navy as 'potential hostiles' when at sea in order to maximize their survivability and to continually train to avoid such threats.
Collisions between submarines were fairly common during the Cold War, and were indicative of the amount of time subs spent playing 'hide and seek' with their opponents - because in order to gain intelligence on other submarines, or even to follow them reliably, subs have to be quite close relative to how long it takes them to stop or turn. As a result, however, most collisions were between or involved attack submarines. For two SSBNs to involved in such a bump, either one or the other had to be involved in SSN-like games, or pretty astronomical odds were just surmounted in a random collision. It's a big ocean. It'll be interesting to see precisely where the damage to the two boats is, as it might tell us what aspect they collided at - I have heard it was a slight angle from head-on. Even that doesn't meant they weren't playing silly buggers - if one submarine turned to check its baffles and the other didn't maneuver out of the way, that could result in an angled head-on.
Well, duh. (Score:5, Interesting)
FTFA
"The Ministry of Defence needs to explain how it is possible for a submarine carrying weapons of mass destruction to collide with another submarine carrying weapons of mass destruction in the middle of the world's second-largest ocean," he said.
See the statement above...
Nuclear engineer John Large (braggart) told the BBC that navies often used the same "nesting grounds".
"Both navies want quiet areas, deep areas, roughly the same distance from their home ports. So you find these station grounds have got quite a few submarines, not only French and Royal Navy but also from Russia and the United States."
It doesn't matter if the parking lot is large, but if the situation is as if Sony is giving away flatscreen televisions, maybe the respective Defense Departments need to find other parking lots.
Ya think?
Re:Odds ? (Score:3, Interesting)
I'd imagine that it is made more likely by the topology of the ocean floor itself; there are probably good corridors through which to travel undetected (especially in 'friendly' water where it's unlikely that the enemy have detector arrays). If both sides are using the same ocean floor map, it seems that the odds of a collision go up considerably if there's an obvious corridor to traverse/hide in.
Re:Whoops (Score:5, Interesting)
Perhaps Sir Humphrey Appleby spoke the truth about the true purpose behind Britain's independent deterrent?...
Chicken of the sea! (Score:5, Interesting)
This is not likely. I have served in the Navy and am familiar a lot of how this stuff works and happens and ultimately, I believe this came down to a game of chicken where neither wanted to change course. Why they didn't want to? Who knows exactly, but acknowledging that you know that someone else is there reveals a lot about yourself that you wouldn't otherwise want them to know....such as that you have the capability to know where they are which is a useful secret in war-time. After all, if they don't know they can be seen, they will think they are invisible.
Re:Stealth Technology is Too Dangerous (Score:5, Interesting)
Being ex Royal Navy myself, I know just ho stealthy these SSBNs really are.
We had a two week exercise with the US Navy to hunt for a Vanguard class sub. The sub said its goodbyes, we gave it a couple of hours then we went hunting. Two weeks later we didn't find it. The sub surfaces, only for them to tell us they have been sitting under one of the destroyers hulls all the time.
Re:Despite each being equipped with sonar? (Score:2, Interesting)
Yeah, but it's not like they were actually at war, right? There's no reason to use passive unless you're trying to sneak around, and unless I'm missing some huge piece of news, the UK and France aren't actively pelting each other with torpedoes at the moment.
Re:Odds ? (Score:5, Interesting)
"The middle of the Atlantic OCean" is a big place. However, "that maneuverable spot between the underwater mountains that shield you from sonar and doesn't have any currents that will smack you into rocks" is not perhaps such a big place, and it's less surprising that such places might be more frequented by submarines playing hide and seek.
In fact, it makes me wonder if _both_ subs were hiding from a Russian vessel nearby and pulled the same tricks of concealment.
Re:Subs don't always use SONAR (Score:3, Interesting)
Re:Whoops (Score:3, Interesting)
Even Brazil uses nautical miles. And we are a country were a good part of the population wouldn't tell the different between a mile and a file.
Topography, not topology (Score:4, Interesting)
I'd like to respectfully correct a very common and understandable error in your terminology. I think you mean "topography" when you talk about the peaks and troughs of the ocean floor. "Topology" is a mathematical term describing the connectivity of sets of points: for example the surface of s sphere has one kind of topology while the surface of a donut has a different kind, because continuous transformations that don't break the 2D surface of a sphere can't morph it into a shape with a hole in it. See http://en.wikipedia.org/wiki/Topology [wikipedia.org] for more if you're interested.
That aside, your point is well-taken that subs might tend to congregate in the same areas due to favorable underwater geological features.
Re:Odds ? (Score:3, Interesting)
The odds are quite good, because the subs don't cruise the ocean at random.
Even the best stealth technology won't help much in clear, open, stagnant sea. It's the background noise you hide in.
The borders of oceanic currents of various temperature and salination water create zones that neatly reflect noises, create quite a bit of background noise themselves, and in short, for a submarine, are what a bunch of seaweed is to a fish - a great place to hide in. Plus they often run for many, many miles along the currents, providing safe, invisible paths for the submarines to travel - sometimes quite narrow though.
So while collision right in the middle of nowhere would be against cosmic odds, a chance of collision on such a path is quite high - both subs are there because this is a good hiding spot, they are -very- invisible to each other, and both stay in the same relatively narrow zone. They may even travel in opposite directions.
Re:Whoops (Score:5, Interesting)
1 hogshead=238.5 L
238.5 L in 1 hogshead
Plutonium 19.86 g per cm^3
1 liter=1000 cm^3
238500 grams/hoghshead
238500/19.86=12009 grams of plutonium(call it 12 kilos)
1 kilo plutonium, fissioned=20,000 tons tnt
240,000 tons tnt
1 ton tnt=4.184 Gj
1004160 Gj of energy per hogshead of plutonium
40 rods=201 meters
1004160 Gj/201 meters
or a hair under 5,000,000,000 kilonewtons
1 newton being the energy to accelerate 1 kilo to 1 meter per second and the earth being a bit under 6,000,000,000,000,000,000,000,000 kilograms, I don't think we'd notice much.
The british sub, weighing about 14,500,000 kilograms, would get something like 344 meters/second out of it. Or just about the speed of sound at sea level. I imagine that might be a first, for a sub, breaking the sound barrier and taking flight(plummeting glide, really) with those stubby dive planes.
Some one will now rip my math into shreds of sobbing uselessness, probably around the newtons to meters/second part.
Re:Odds ? (Score:2, Interesting)
Re:A bit of factness. (Score:4, Interesting)
Remember, a few years ago, when Google's satellite view showed a US Submarine in drydock with its propeller fully visible? That was a huge, huge deal.
Actually, it was Microsoft's mapping service that had this: Here's the picture. [live.com]
And yeah, apparently it was a big deal [google.com].
Re:Stealth Technology is Too Dangerous (Score:2, Interesting)
I don't doubt that. If I recall it right, during an exercise a Norwegian Kobben-class (!) submarine completely avoided detection, and hid below a US carrier. To add to the insult, they even surfaced and took pictures of the carrier's hull. Talk about major embarrassment. It should be safe to presume that most submarines in use today have vastly better stealth-capability, so it's no surprice that they can linger about undetected.
Re:Odds ? (Score:3, Interesting)
Indeed, Sherry Sontag's Blind Man's Bluff [amazon.com] tells a lot of interesting stories about Russian-American submarine escapades during the Cold War. Sometimes our Navies seemed less like proud defenders of the motherland and more like dumbass high school kids playing chicken.
Yea, but it was fun and you got paid for it.
Re:Whoops (Score:3, Interesting)
How submarines navigate (Score:3, Interesting)
Add to that that submarines don't exactly report to each other where they are.
The odds of a submarine hitting anything in the oceans is extremely remote. It's very very hard to fit your head around the cubic volume of the oceans, even when you have a submarine limited to only the top 1000-3000ft of it!
This is the very definition of a freak occurance.
Infact so unusual and unlikely that I'm quite certain these two submarines were somewhat aware of the presence of the other, were likely following and playing a bit of cat and mouse perhaps (really what else is there to do down there?). But both running silent and lacking any positive fix, there would always be the chance of a collision. No surprises they collided at slow speed - this would be right if they were in maximum stealth.
Re:Stealth Technology is Too Dangerous (Score:3, Interesting)
Questions to navy/sonar folk... is active sonar used by surface fleets (e.g. carrier groups) every so often, so they don't sail right past subs floating silently in wait?
And are they detailed enough to distinguish between hulls in such close proximity, like the sub under the destroyer hull in the exercise?
If not (to either question), what's to prevent an enemy sub from pulling exactly this trick?
Boomers don't play games... (Score:4, Interesting)
Been there, done that. When you are in your patrol area typically you are making turns for 3 knots or less. If you get a contact you try to avoid it without either leaving your patrol area or being detected yourself.
Occasionally your are either unable to estimate the range to a contact due to a technical reason or sonar just blows the estimate. That's what happened to us. We had him on sonar: a weak sound level with a zero bearing rate -- sonar told us he was far away.
Our collision was with a Russian boat. We had just started to clear baffles to port when he hit us on the starboard side just forward of the sail. He took out all the forward ballast tanks on the starboard side. If we hadn't just started to clear baffles to port he would have T-boned us and it would have been a lot uglier for us.
He had no clue that we were there -- he thought he had hit the bottom (immediately he lit off his fathometer on the short scale) --- the water was 6,000 feet deep. His reactor plant scrammed, he started flooding and had to surface. We just went deep and snuck away.
I know the U.S. boats and systems are much tougher than many think and I am certain the British and French boats are comparable.
Re:Whoops (Score:3, Interesting)
Well, in English if you are traveling North and need to turn West, then going left is right but going right is wrong.
Which might explain why USA politics has gotten itself into such a mess. We really need another Abott and Costello team to get our directions straignt again.
Re:Stealth Technology is Too Dangerous (Score:2, Interesting)
I'm reminded of a story I heard about two US Navy battle groups playing war games. The commanding officer of one of the groups was frustrated because the other always seemed to know *exactly* where he was - it's a big ocean, and carriers routinely launch from well out of radar range from their targets, and yet the other CO always knew where to send his planes.
The CO then got an idea, and asked the sonar operator what the current depth was. The sonarman responded that the depth sounder was broken; ever since leaving port it had read 300 feet. The CO called another ship in his group and asked them to fire a sonar pulse beneath his ship, and discovered that an opposing submarine had been shadowing his group throughout the entire exercise. Nobody - not even the destroyers who were supposed to hunt subs - had caught on.