The Norks are Suspected of Sinking South Korean Shipping.

[Kanastrous]

It's a telephoto shot and part of the bow is still submerged. Perhaps the section is bigger than it appears in the picture?

[FSTargetDrone]

It appears the amidships was more or less wrecked and the ship torn in three pieces rather than two, since it didn't mention that as being an artefact of the salvage; I was expecting to see a much longer bow section, instead we get this. That suggests, though this still just speculation, that if the blast was external it had to be under the keel.

Yes, it appears a sizable section of the center is mostly gone or shredded. As mentioned in one of the articles and seen in the picture, the whole mast is gone and everything between it and just forward of the stack (which is also gone, but the structure below it seems mostly there. What was raised seems to be missing, (at least to my untrained eyes, comparing all the images) what, roughly 1/8th of the length? Granted, it is hard to tell with these different angles, but there's a good chunk of the ship gone.

[CJvR]

It appears the amidships was more or less wrecked and the ship torn in three pieces rather than two, since it didn't mention that as being an artefact of the salvage; I was expecting to see a much longer bow section, instead we get this. That suggests, though this still just speculation, that if the blast was external it had to be under the keel.

No it is probably just two, although the area under the stack have failed structurally. Compare the length os the forward gun deck with the elevated deck behind it and you will see most is still there.

[The Duchess of Zeon]

It appears the amidships was more or less wrecked and the ship torn in three pieces rather than two, since it didn't mention that as being an artefact of the salvage; I was expecting to see a much longer bow section, instead we get this. That suggests, though this still just speculation, that if the blast was external it had to be under the keel.

No it is probably just two, although the area under the stack have failed structurally. Compare the length os the forward gun deck with the elevated deck behind it and you will see most is still there.

Well "middle" section in this case is the shredded area which is no longer intact. I would argue, yeah, it's about 1/8th of the length of the ship.

[Stuart]

I agree; I don't think there is much missing. We can see the stump of the mast in the bow picture (it's at an oblique angle so it's foreshortened) and where the superstructure deck ends. In the aft picture we can see the stump of the funnel (that was seperated from the wreck) and allowing for the tangled mess, that's all she has. She is only a 1200 ton corvette after all.

What surprises me is how little shock damage has been done. The gun mounts are still sitting on their rings, the anti-ship missiles are still on their rails, even the glass in the bridge is unbroken. If this ship had been hit by a UTK (under-the-keel shot) there would be shock effects all over the ship. For example, on Princeton, the security vault hatch was detached from its frame and thrown more than a hundred feet. Having said that, I can see why people have made a tentative conclusion she suffered an external explosion. The curve on the wreckage of the stern is quite a pointer to that. By the way, I happen to know she was doing six knots only at the time she went down (as opposed to the 12 knots ordered).

[CJvR]

I dont think you woulc get enough of a shock wave in the air to shatter the rather heavy duty windows from an under the keel detonation. The energy is undoubtedly there but by the time it reaches the ends of the ship it will have spent much fury moving water, ripping steel, lifting the hull and bouncing around the hull and sea.

[Stuart]

I dont think you woulc get enough of a shock wave in the air to shatter the rather heavy duty windows from an under the keel detonation. The energy is undoubtedly there but by the time it reaches the ends of the ship it will have spent much fury moving water, ripping steel, lifting the hull and bouncing around the hull and sea.

Wouldn't be an airborne shockwave, it would come through the structure of the ship. There is one hell of a thump when the UTK goes off; in fact there are several. The first is when the gas bubble from the explosion hits the keel of the ship forcing it upwards. Then, the bubble oscillates causing intense vibration. At that point the UTK bubble starts to collapse sucking the hull down. Finally, because the bubble is an ellipse (flattened by the hull of the ship)but is collapsing symmetrically, the water under teh bubble effectively forms a diffuse shaped charge jet and punches straight through the ship's bottom. That's what breaks her in two. These sequence of shocks sets the whole ship's structure vibrating. Now, heavy-duty glass will fracture more easily under those conditions than lighter glass because it won't flex. I'd have expected to see a lot of shock damage and it just isn't there. I'm beginning to see why the Koreans are being so circumspect about this; there's a few things here that don't add up.

Here's another theory for you; a limpet charge attached to the hull on a time fuze. It was set on the ship's hull in port with the timer set to blow her in deep water. But, the ship did 6 knots not 12 so she was still in shallow water when she blew. That is still a theory without any evidence to support it and it plus five bucks will still get you that cup of coffee.

[Surlethe]

Wouldn't be an airborne shockwave, it would come through the structure of the ship. There is one hell of a thump when the UTK goes off; in fact there are several. The first is when the gas bubble from the explosion hits the keel of the ship forcing it upwards. Then, the bubble oscillates causing intense vibration. At that point the UTK bubble starts to collapse sucking the hull down. Finally, because the bubble is an ellipse (flattened by the hull of the ship)but is collapsing symmetrically, the water under teh bubble effectively forms a diffuse shaped charge jet and punches straight through the ship's bottom. That's what breaks her in two.

Is that what's going on with this ship bucking up, then settling, then the explosion tearing it apart?

That is still a theory without any evidence to support it and it plus five bucks will still get you that cup of coffee.

That's because Starbucks is wildly overpriced.

[Shroom Man 777]

Aside from the North Koreans with their whole "external pressure for domestic stability" thing, who else can possibly gain from this provocative action? Since the only ones who'd likely do this act would be the ones who'd benefit/profit from it, and now it seems like someone's taken a lot of trouble to sink the S. Korean ship in a way that's not conclusive or obvious at all and ends up leaving people to do all sorts of guessing games, head-scratchings, and butt-thumbings?

[Stuart]

Is that what's going on with this ship bucking up, then settling, then the explosion tearing it apart?

Isn't that a wonderful film? You can see the ship lifting, then being sucked down and finnaly the water jet tearing her apart. That last bit isn't an explosion, its purely the jet of water formed by the collapsing bubble.

That's because Starbucks is wildly overpriced.

So's my opinion

[CJvR]

Wouldn't be an airborne shockwave, it would come through the structure of the ship. There is one hell of a thump when the UTK goes off; in fact there are several.

Yes it would, but it wouldn't arrive as one sharp wave front like a massive close surface blast. The hull just isn't strong enough to transmit that much energy which is why it is ripped to shreds. Unless the component is located close to and firmly attached to the keel it shouldn't get hit by that much energy.

[CJvR]

It appears the amidships was more or less wrecked and the ship torn in three pieces rather than two...

More like two big pieces and shrapnel...

[Stuart]

]Yes it would, but it wouldn't arrive as one sharp wave front like a massive close surface blast. The hull just isn't strong enough to transmit that much energy which is why it is ripped to shreds. Unless the component is located close to and firmly attached to the keel it shouldn't get hit by that much energy.

You'd be surprised. For example, when Princeton was hit, the shockwaves damaged the forward gun mount at the other end of the ship, cracked open deadlights in watertight bulkheads, sprung watertight hatches that had been dogged shut, threw sailors into the overhead and worked worm gears against the screw (which I thought was impossible but still). Both shafts were thrown out of alignment, the foundations of the gas turbines were cracked, the Harpoon missiles were tossed 18 feet into the air and there were six inch wide cracks formed in the superstructure. The damage report makes fascinating reading; (ask Mark nicely and he'll probably be able to find it for you). That was a relatively small mine that exploded some 350 yards away from the ship. (As a by-the-way, the mine is almost always described as being a Manta. In fact, a Manta was about the one type of mine it couldn't possibly have been. The most likely candidate was an MRP-80).

Another aspect to bear in mind is that the Korean corvette was small. She is about a third of the size of the frigate shown in the film clip. A heavyweight torpedo would have done a hell of a lot more damage and few people would have got off her alive. Oddly, the limpet mine makes more sense the more I think about it. A plastic-cased 20 or 30 pound fuze with a soap time delay would give the kind of damage indicated, would leave no identifiable fragment damage, and give no radar or sonar warning. Its still a guess though, no more than that

[FSTargetDrone]

Some slightly better views of the damaged areas of the aft section:









Incidentally, this is the crane barge that is being used in the recovery:

[Sephirius]

I'm sorry, but to me that looks like a definite torpedo strike, especially with the later pictures. The hull rippling is what gives it away along the keel. a limpet mine usually doesn't do that.

[Molyneux]

I'm sorry, but to me that looks like a definite torpedo strike, especially with the later pictures. The hull rippling is what gives it away along the keel. a limpet mine usually doesn't do that.

I'm not very knowledgeable on this subject - is there anything else that could have been responsible? Some kind of problem on-board?

[FSTargetDrone]

Latest:

(4th LD) S. Korea raises remaining half of sunken naval ship

By Chang Jae-soon

SEOUL, April 24 (Yonhap) -- South Korea retrieved the remaining half of a sunken naval ship and the body of a missing sailor trapped inside Saturday, with experts saying the wreckage shows signs that the vessel was dealt a blow from outside amid suspicions of a North Korean attack.

The 1,200-ton patrol ship Cheonan mysteriously broke in half and sank on March 26 near the Yellow Sea border with North Korea. The ship's broken stern was raised last week, and investigators immediately blamed an unexplained "external explosion" as the most likely cause.



On Saturday, the vessel's bow was salvaged, and part of its bottom appeared to have been blown off diagonally, informed military sources said. The images of the ship's two broken pieces, if put together, show that the vessel's central bottom is shaped like an inverted V, an indication that it was struck by a blow from outside, they said.

Also gone were the ship's chimney and its radar mast that were on the top center of the ship.

Salvage workers found the body of petty officer first class Park Sung-kyun, 20, after a crane raised the bow from the sea. The wreck was later placed on a barge, and naval rescue workers combed it for other missing sailors as investigators sought clues as to what tore the vessel apart.

Forty sailors were confirmed dead but six others are still listed as missing.

"An explosion is believed to have occurred near where Park was found," a military official said, speaking on condition of anonymity. But the official declined to comment further on a possible cause.

North Korea's involvement was suspected from the beginning as the site of the sinking lies near where the navies of the two Koreas fought bloody gun battles in 1999, 2002 and most recently in November last year.

But the communist North has flatly rejected allegations of its involvement as fabrication.

The Navy planned to move the salvaged bow to a naval base in Pyeongtaek, some 70 kilometers south of Seoul, later for a detailed inspection. Examining both of the broken-off sides of the ship could provide more clues into the deadly disaster.

In an effort to improve the transparency of the probe, South Korea has asked foreign countries to send experts to conduct joint research. Specialists from the United States and Australia have already been working in South Korea, and Sweden and Britain also pledged to send experts.

North Korea's involvement, if confirmed, would deal a serious blow to the already troubled relations between the two divided states and cast a pall over international efforts to reopen long-stalled disarmament talks on Pyongyang's nuclear arms programs.

South Korean President Lee Myung-bak has vowed to discover the cause of the sinking, respond sternly according to the investigation's results, and make South Korea's armed forces stronger, though he cautioned against rushing hastily to a conclusion without clear evidence.

On Friday, North Korea accused the South of trying to link the regime to the sinking and making the situation on the divided peninsula reach "such extreme phase that it is at the crossroads of a war or peace."

U.S. Secretary of State Hillary Clinton warned the North against any provocations.

"I hope that there is no talk of war, there is no action or miscalculation that could provoke a response that might lead to conflict," Clinton said at a NATO foreign ministers' meeting in Tallinn, Estonia, Friday. "That's not in anyone's interest."

In New York, the U.S. representative for North Korea policy, Stephen Bosworth, said he is still optimistic on the reopening of the North Korea nuclear talks despite the ship sinking.

"As we look ahead today, we of course face a set of uncertainties in the short-term as we await the results of the investigation of the sinking of the South Korean naval vessel," Bosworth told a seminar in New York.

"But looking beyond that I think that there is reason to believe that multilateral engagement remains the essential condition for making progress on greater stability, denuclearization, peace and prosperity on the Korean peninsula," he said.

EDIT:

More pictures.







Including the mostly-profile view of the aft section as seen earlier in the thread. We almost have a complete view from the side...



...compared to a reversed image of the profile of the Iri, Cheonan's sister ship of the same class, as seen earlier:



Anyone want to try to make a crude reconstruction?

[FSTargetDrone]

Edit, that should be, Iri is "of the same variant" (as far as I know, as discussed earlier).

[Surlethe]

I'm sorry, but to me that looks like a definite torpedo strike, especially with the later pictures. The hull rippling is what gives it away along the keel. a limpet mine usually doesn't do that.

What are your qualifications, to make these statements?

[The Duchess of Zeon]

Wow, I've never seen a ship broken in two with that kind of < < pattern in the crack of the hull; everything I've seen is much, much straighter than that, jagged edges to be sure but the level of displacement in where the hull was sundered is very impressive. Now that I can see the damaged area I can see why I thought there was a third section and how there mostly isn't. To answer the questions about reconstruction: No, those pictures are at a bad angle for it, still.... looking over the hull very carefully, the boxlike deckhouse right forward the funnel sat over an area of hull which is now completely missing. The position of the funnel corresponds with the forwardmost part of the aft section intact; the position of the gap between that square deckhouse associated with the funnel and the forward superstructure corresponds with the sternmost part of the bow section intact. The area of hull directly under that deckhouse was what was shredded into virtual nonexistence. So the blast occurred right forward from the uptakes.

[FSTargetDrone]

More:

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12. (from the port side of the ship)


In images 06-12, you can see what appears to be the previously-unseen stack section that is resting on the deck of the barge, separate from the majority of the forward section, with a cluster of torpedo launchers attached to it.

Does anyone know what that whitish-yellowish scarring is that is most visible in image 02?

And doesn't the aft section look to be in better condition than the forward section overall (notwithstanding the great damage where the 2 should be attached, of course)?

[Stuart]

I can hazard a *****guess***** as to what happened after the ship was hit. I don;t think she was completely severed with the initial explosion (there's no real doubt now that there was an explosion of some sort, the question is what caused it). It looks to me as if the hull was riven to starboard. The stern section remained floating upright (probably because the weight of the diesels stabilized it). The bow section started to roll to starboard quickly and eventually tore free and sank. That's why the rupture line is diagonal, the bows were effectively twisted off. The ripples in the hull side point to that as well. That suggests that the bow section went down quickly while the sterm continued to float for some time. That suggests the bows are close to what CSI would call "the primary crime scene". There's a 7.2 km distance between the place where the bows went down and the site of the stern sinking.

Portside is in much better condition than starboard side which fits into all this. I'm reasonably sure this was either a contact explosion or a very small/distant UTK. Korean ships are not very solid (look at the hungry horse plating) so I doubt if a full-size heavyweight torpedo would have done damage limited to the center section like this. The actual spread of the damage is very limited, the gun mounts aft for example are pristine and there is no sign of shock damage to the Harpoon canisters (a key thing to look for in all of this is teh seal on the end of the canister. With shock damage, the missile is hurled forward and bursts that seal before sliding back into the tube. That's a very . . . . diagnostic . . . . piece of damage.

[Stuart]

Does anyone know what that whitish-yellowish scarring is that is most visible in image 02?

Probably as simple as mud. That's the side she went down on. Most of that damage is from the sea bed and from the chains used to lift her.

And doesn't the aft section look to be in better condition than the forward section overall (notwithstanding the great damage where the 2 should be attached, of course)?

It do indeed. That's why I'm certain the bows rolled over and went down while the stern stayed more or less upright.

[The Duchess of Zeon]

I can hazard a *****guess***** as to what happened after the ship was hit. I don;t think she was completely severed with the initial explosion (there's no real doubt now that there was an explosion of some sort, the question is what caused it). It looks to me as if the hull was riven to starboard. The stern section remained floating upright (probably because the weight of the diesels stabilized it). The bow section started to roll to starboard quickly and eventually tore free and sank. That's why the rupture line is diagonal, the bows were effectively twisted off. The ripples in the hull side point to that as well. That suggests that the bow section went down quickly while the sterm continued to float for some time. That suggests the bows are close to what CSI would call "the primary crime scene". There's a 7.2 km distance between the place where the bows went down and the site of the stern sinking.

Portside is in much better condition than starboard side which fits into all this. I'm reasonably sure this was either a contact explosion or a very small/distant UTK. Korean ships are not very solid (look at the hungry horse plating) so I doubt if a full-size heavyweight torpedo would have done damage limited to the center section like this. The actual spread of the damage is very limited, the gun mounts aft for example are pristine and there is no sign of shock damage to the Harpoon canisters (a key thing to look for in all of this is teh seal on the end of the canister. With shock damage, the missile is hurled forward and bursts that seal before sliding back into the tube. That's a very . . . . diagnostic . . . . piece of damage.

Stuart, the reports from the survivors are supposedly that the bow remained upright and floating whereas the stern sank immediately. Do you think that's intentional misinformation by the ROK?

[Stuart]

Stuart, the reports from the survivors are supposedly that the bow remained upright and floating whereas the stern sank immediately. Do you think that's intentional misinformation by the ROK?

No, I think its just general confusion. Pretty much everbody in the stern section died (the enlisted living spaces are in the middle of that tangled mess) so the only reports available are from the bows. There is no doubt the bows did roll over as the ship went down, and the stern didn't. The wreckage shows that very clearly. The heavy damage to the starboard side of the bow and the lack of any such damage to the sterm is a dead give-away. As to which went down first, in the darkness and confusion, anything could have happened.

It's quite plausible that, once the bows rolled and ripped away, the stern sank while still on an even keel while the bows took a bit longer to complete rolling over. This is why hypothesizing at this stage is so dangerous, we really don't have enough data to work from. My "official" position at the moment is that there is inadequate evidence to support any firm conclusion and any theory so far is speculative at best. That's what people who phone me and ask get told.