We are talking about a region, which was the front line for years in the Korean War. On Wikipedia it written that they area was not regularly patrolled by Korean corvettes and was considered not to be save for such big vessels. This hints to navigational hazards, which could indicate that there was no systematic search for mines in the area.

There are shoal waters in that region that are hard to sail. If they are not generally navigable waters why would they have been mined in the 1st place?. Again if the report, from the surviving crew, was for a random unexpected blast breaking the ships spine, in a ‘former front line area’ why no route survey work prior to pushing heavy salvage vessels in?.

If there was a torpedo attack, they should had been cautious to send salvage vessels in the area – there would have been the possibility of another attack.

A torpedo has to be fired by someone. A corvette explodes….then a salvage vessel goes down the same way?. Stretches the concept of accidental loss a bit that one doesn’t it?. You are assuming that the firing platform was playing the part of aggressor. An evading submarine could try for shoal waters, if the skipper knew them, to dodge an ASW escort by hiding in the flow noise and active sonar nulls. An SSK hounded to such a degree, with a depleted battery and low o2 reserves etc, could turn and fire on its pursuer as part of an escape manoevre. It wouldnt be an entirely rational act, but, under stressful conditions rationality is a variable!.

It would be really interesting what exactly was happening and what does the the sensors of the Cheonan did detected.

They would answer many questions.

I would consider it to bad luck – but not totally unrealistic. Do you ever lived on or nearby a former battle field? And do you ever had the situation that a complete quarter of a city has to be evacuated because a bomb, which did not exploded 65 years ago? We have this regularly…

Yeah Liverpool docks got a fairly liberal coating in the last war so I know what you are saying, but, I dont really understand what comparison you think there is here. A city that was actually targetted in concentrated and deliberate fashion in a war is bound to have a fair bit of unexploded ordnance knocking around. This is a patch of open water. Unless a minefield was deliberately laid there why would unexploded ordnance be present?. Ground influence mines don’t drift and, as we saw from the wreckage, this wasn’t a contact mine detonation.

They should have detected a least the running torpedo – and probably also the submarine itself, because such an old design is probably relativity noisy for a Diesel sub.

Depends on an awful lot of things. Who’s torpedo it was, who’s sub fired it, if it was indeed a sub (see Wanshan’s point about the submersible torpedo boats), how good was the skipper of the firing vessel, what was the South Korean doing immediately before the ‘hit’ etc, etc. I think we can accept the fact that it was a HWT hit without being forced into the conclusion that it was the North Koreans who did it and, similarly, even if it was the NK’s that it immediately means that it was an unprovoked attack.

You are right, though, in that if the ship had its sonar station manned they should have detected torpedo screws. Perhaps thats the reason why they weren’t hesitant in sending the salvage vessels into the area.

Which should be possible, if the mine has a magnetic detonator.

The chances that there is still unexploded ordnance are pretty high – if you see how often unexploded bombs are found in middle of European cities or how many mines are still in European waters…

Yeah, you aren’t quite getting this Leon. To get the effects that happened to the ship it has to be in less than 100ft of water, more like 60ft to get that kind of devastation, and the ship would have to pass DIRECTLY over it i.e not 100ft to port or starboard. Ground mines dont generally get laid in isolation either….they would be laid as a pattern. If this was a ground infuence weapon I see a strange lack of SK minehunters deployed to neutralise the rest of the field.

A magnetically triggered weapon is almost a given owing to the detonation point in the hull. Its just that the chances of it being a mine are slim and some ‘long lost’ mine left over from an old action even slimmer.

What parellel do you think exists between unexploded ordnance in a city and that in naval warfare?.

If it’s a direct hit, then it is very easy to find traces of explosives (+ traces of torpedoes) on the wreckage of the ship!

Not a direct hit – it would be an under-the-keel detonation. Under the keel exploders, if you have a torpedo that is reliable at holding depth to start with, isnt a huge modification to fit to even an older type torpedo. All it is is, very basically, an upward pointing magnetometer, a few circuit boards and a line into the warhead detonator.

Speed range (35knts) and warhead size called above fit the general parameters for several nations HWT’s – including Chinese Yu-3 and -4 type weapons known to be/have been deployed with the Chinese Romeo SSK variant.

Actually, there are quite a few valuable uses for the Vikings, even now, should they be brought back.

Not really Ed.

Overland surveillance they can indeed sweep to find freshly planted IEDs. Better still though to have a persistent platform able to watch the bad guys planting the IED’s in the first place!. In terms of high endurance ISTAR ‘product’ a manned platform is always going to be second best.

For Littoral ops otherwise known as ‘force protection’ you are talking about lightly armed speedboats and the suchlike as threat systems?. Threat systems who’s effective strike range is measured in hundreds of yards. To counter these you need a decent surface search set and a sharp lookout routine. These speedboats are coming in at 40knts or so….catch them at 15nm standoff and you have over 20 minutes to bring the ship to action stations surface!. A twin jet, bells & whistles patrol bomber that needs either a handy CVN or friendly shore base-in is scarcely a necessity.

Could S-3 be a stand-in land-based MarPat type. Yes. Definitely, but, the question is likely to be how it compares with something like the ATR42MP. Seeings as you can buy a brand new one of those for 30mn Euro’s and get twin-prop airliner running costs. S-3 is more capable of course…..but if you dont NEED all the extra capability…..???

North Korea has no modern submarine. It appears to have no modern naval equipment at all. Is there any prove that it has modern heavy weight torpedoes?

Why does it have to be a modern submarine or a particularly modern torpedo to defeat one small, austere, surface combattant operating on its own?. North Korea’s submarine service has no shortage of old Romeo class boats that are capable, in Chinese service at least, of deploying Yu-3/4 type torpedoes which would fit the profile of the weapon that killed this ship. North Korea has, allegedly, been confirmed as having taken delivery of Yu-3G torpedoes for the submarine fleet.

The S-3’s primary target set pretty much vanished as an effective opposition overnight. You dont hunt SSK’s with CVN’s and S-3’s….you use LFA towed arrays, pinger choppers and SSN’s. At the end of their carrier careers they were little more than an expensive way to undertake force protection.

The S-3’s were always more limited by cat/trap cycle limits than airframe life so the examples in storage should have plenty of life left. Question is whether the refurbed S-3’s would offer much over what the Reapers etc are doing and whether it might be more cost-effective, in terms of ISTAR product delivered, just to bring in more of the UAV’s.

Now there is a solid argumentation. Thank you, sir, you’ve brightened my day!

Looked at the images here, posted by Tango: given where the hull broke and the extent of hull that appears missing, is there any way this type of damage could have been caused by an accident (e.g. some massive engine room explosion)?

Yes it was poorly written many apologies for that. Started off talking about facts and ended up on probabilities!. Poor form on my part!.

The missing bits of hull will have been seperated off in the shearing action as the bow and stern seperated. Could it have been an explosion aboard?. There is no evidence to support it. Simply there is no apparent scorching, no sign of fire and no sign of a powerful internal explosion. Even if it was a blast below the waterline you would expect to see blown out hull plates etc. They just dont seem to be there.

This looks far too much like an under the keel detonation for coincidence. Hate to fall back on Occums Razor but it is the simplest explanation. Are there any images from the opposite beam yet?. I noticed from those shots that the port side torpedo mount was still trained inboard, if my ship was under torpedo attack, and I knew about, I’m sure I’d have at least had an ASW torp ready to counterfire?.