Three submarines damaged by earthquake

I can’t honestly believe that it was the wave that caused damage to the submarines. A tsunami has an extremely long wavelength far out at blue water; it’s when it reaches shallow water where massive amounts of water in the depth pushes upwards and creates a waveheight of 20 meters or so the danger occurs.

The could however be shaken by the earthquake, causing a water shock, but that is not connected to a tsunami.

Castor

hmm, by what was this tsunami created? :p
I think when there is a large surface impact the sub might already be dead (eg large meteorites, 200ft wave is very tall, won’t be generated by an ordinary planecrash). Hence a more modest wave of 20m (about 60ft) would be more accurate/possible I suppose. These waves happen more too (called freak waves, waves taller than 18m, while all the surrounding waves are “only” 12m tall). With this hight, the questions comes to mind: do submarines often sail close to their collapse depth? I don’t think so, not like 20m above it, too risky for dayly operation. And a 20m wave won’t necessarily have the weight of all the water it contains, since it’ll have an upward acceleration (hence it’s formation).
But then theoretically seen I suppose you’re right, it might pose a danger to submarines, when they are very unfortunate. (we don’t have trouble with that kind of things 😉 , occasionally a bulkcarrier sinks by a 25m freak wave, but that’s it )

The picture shows (Gorshkov/Vikramaditiya :p ), this is caused by “painting stresses”, wave piercing. The constant load and unload of the oncoming waves. I think a very strong pressure wave might do the same with a submarine’s bow, certainly when you consider they have a relative “soft” nose (with the sonars) compared to these ruggid merchant ships.

Hi Jonesy, very interesting. I have a difficulty in reasoning why broadside is worse. If it’s a wave, then turning into it would mean a bigger difference in pressure distribution due to the moment arm, thus creating huge high stress areas around the node of the pressure wave. But, being broadside means the wave pass it as fast as possilbe. I understand the problem for a boat/ship in terms of stability but i dont’ quite see the reason for a sub.

Havent seen you about in a while Vortex nice to see you back!.

Youre thinking about the pressure=force/area calculation?. Its true that the bow on aspect will subject greater forces on that area, but, the bows are designed to pierce waves and tolerate much greater forces. The beam aspect presents a much greater surface area to the wave which, if the boat was a pure cylinder, would be little issue. What happens in fact though is that the tower/sail acts to generate a rotational force around the long axis pushing the boat over into a capsize. It also can generate shear forces on the screw and main shaft from the perpendicular shock pulse. May not be enough to rip the screw off but certainly danger exists in popping shaft seals etc.

Normally when such things happen, a wave is only formed in shallow waters. So at 3,000m deep, the energy will go horizontally, when it reaches shallow waters, it is directed upwards and forms a wave.

..and you’re quite right Roel, for a tsunami created in such a fashion as this i.e by an underground siesmic event. The effect is a shock wave travelling horizontally through the water that only really ‘climbs’ into a surface wave when it hits a continental shelf edge.

For a tsunami created by a large surface impact or a large-order near-surface explosion though a surface wave is created and, for a submarine at 500ft depth, a 200ft wave over the top adds the ‘weight’ of that water to the pressure already on the sub hull. The effect is, over a short interval, that the sub would be subject to the stresses of 700ft depth. The results of that being potentially unfortunate.

I don’t really agree with Jonesy,
Normally when such things happen, a wave is only formed in shallow waters. So at 3,000m deep, the energy will go horizontally, when it reaches shallow waters, it is directed upwards and forms a wave. That is also why no real shipdisasters happened during the seaquake, the surface ships probably hardly noticed it. Maybe by some extraordinary swell or current, but that’s about it. It’s only when you’re close to shore that you’ll have trouble with the formed wave/tsunami.
As for submarines, since they’re below the surface, they are in the horizontal zone where the energy is mostly moving, hence the second effect jonesy mentioned, the pressure wave, is indeed there and very dangerous.
I don’t know too much about a submarine’s stability, but basing my thoughts on surface ships, it must be very hard to stabilize a submarine and I think it is therefor not that stable. The pressure wave could tip it over. It could also damage the sub enough to disable it, hitting diving planes, ballast tanks etc.
One thing is sure, I wouldn’t want to be on a submarine when such things happen!

i asked about the time scales (thanx for the answer) as even if a message had got through, 2 hours is no way enough time to evac. in fact it would have caused more chaos would it not?….. so i dont think the article saying if the indian sub had got its message through the disaster would have been minimised (sp) is fair……

When we talk about the term in the vicinity of the epicentre, we are talking about somewhere near Indonesia or more importantly near Andaman and Nicobar islands. You would expect Indian sub to be there because of IN base on the islands. PLAN sub might have been trying to get a peek at the new Indian base and US sub probably shadowing PLAN sub.

How the hell would anyone know where any submarines are? They don’t report their positions to the press and definitely not to other countries. I haven’t heard any of this from the US or Chinese side.

I doubt the PLAN operate nukes or any subs (for one thing the SSKs don’t have the range) in the IO. A pretty iffy and unsubstantiated report.

Exactly Dreadnought…very few quiet earthquakes in recorded history!.

The question about the term ‘in the vicinity’ is a good one. Its an obvious assumption that the Indian boat, being an SSK, could be closer inshore than the US boat and maybe the Chinese boat (if it were one of the Han SSNs). I have a hard time believing that the Indian boat was first to accurately analyse the seismic event for what it was, unless the boat was right over the epicentre, due to the huge superiority of US SSN sonar/processing capacity over anything bolted into an Indian Kilo or 209. Its not like thats a significant issue in the whole scheme of events though.

Can a tsumani hurt a submerged sub….yes very much so. A tsunami is, essentially, a very large wave generated by a shock event and as much as it deposits water ashore when it breaks it carries that water as it travels. This means there are two effects at work that can threaten a sub in the waves path. First is the shock pulse – a pressure wave travelling at many hundreds of metres per second that will hit a hull much like the the shock wave from a depth charge. Second is the extra volume of water the wave carries over the sub. This has the effect of adding the wave mass to that of the water already above the sub and can lead to a sudden increase of crush forces on the hull for a short period.

Turning into the wave and going shallower will mitigate both effects on the hull, but, if the sub is caught deep and broadside on to the wave it could mean big problems.

Hi Jonesy, very interesting. I have a difficulty in reasoning why broadside is worse. If it’s a wave, then turning into it would mean a bigger difference in pressure distribution due to the moment arm, thus creating huge high stress areas around the node of the pressure wave. But, being broadside means the wave pass it as fast as possilbe. I understand the problem for a boat/ship in terms of stability but i dont’ quite see the reason for a sub.

Exactly Dreadnought…very few quiet earthquakes in recorded history!.

The question about the term ‘in the vicinity’ is a good one. Its an obvious assumption that the Indian boat, being an SSK, could be closer inshore than the US boat and maybe the Chinese boat (if it were one of the Han SSNs). I have a hard time believing that the Indian boat was first to accurately analyse the seismic event for what it was, unless the boat was right over the epicentre, due to the huge superiority of US SSN sonar/processing capacity over anything bolted into an Indian Kilo or 209. Its not like thats a significant issue in the whole scheme of events though.

Can a tsumani hurt a submerged sub….yes very much so. A tsunami is, essentially, a very large wave generated by a shock event and as much as it deposits water ashore when it breaks it carries that water as it travels. This means there are two effects at work that can threaten a sub in the waves path. First is the shock pulse – a pressure wave travelling at many hundreds of metres per second that will hit a hull much like the the shock wave from a depth charge. Second is the extra volume of water the wave carries over the sub. This has the effect of adding the wave mass to that of the water already above the sub and can lead to a sudden increase of crush forces on the hull for a short period.

Turning into the wave and going shallower will mitigate both effects on the hull, but, if the sub is caught deep and broadside on to the wave it could mean big problems.

Would the subs have detected the killer wave?

ever seen “the hunt for red october”???

sisemic activity makes sounds

How in the name of Pete will a tsunami affect submerged submarines?

Unless they were floating and not submerged, which brings us to another question – what about all the ships that were at sea at that time?

all three submarines were in the vicinity of the epicentre
Indian ocean may be huge but since they were all close to the epicentre, they would be close to each other.

that still means nothing…

Where did it say the subs were close to each other? You seen how frickin big teh Indian Ocean is!?

all three submarines were in the vicinity of the epicentre
Indian ocean may be huge but since they were all close to the epicentre, they would be close to each other.

Would the subs have detected the killer wave?

a quick qusetion before i post again….. but how long would the wave have taken to get to the mainland from the time of the earthquake???

The 1st wave hit us (Sri-Lanka) little over 2 hours after big quake…travelled something like 1600 (or more) km…

a quick qusetion before i post again….. but how long would the wave have taken to get to the mainland from the time of the earthquake???

This is couple of weeks old, but I did not find it here.

Three submarines damaged by earthquake

30 December 2004: Three submarines of the Indian, US and Chinese navies were damaged by the earthquake off Sumatra that triggered of killer tsunamis in Asia, and while two submarines have returned to their bases, there is no intelligence on the Chinese vessel.

Top sources said that while the American submarine was the first to record the intensity of the tremor, because of advanced sonographic sensors, and dashed off nearly ten messages to its headquarters in California and Pacific base in Hawaii, the Indian vessel was to first to identify the earthquake, but its signal to its mainland base did not produce realtime reaction.

“Both the US and Chinese submarines reported a ‘strange undersea development’,” said a diplomat, “but only the Indian submarine got it right the first time, but its base could not react fast enough, and if it had, the tragedy of such proportions could have been minimised.”

Diplomats say that all three submarines were in the vicinity of the epicentre, and that they could have been flipped over by the quake, suffering damages in the process.

Link:
http://www.newsinsight.net/nati2.asp?recno=3104

PLAN in Indian Ocean??
Also 3 subs close to each other. US and Indian subs following Chinese???
Or it could be any other scenario

Where did it say the subs were close to each other? You seen how frickin big teh Indian Ocean is!?