Yuan Class AIP & Kilo Submarine Thread

[Lezt]

Re: PLAN Yuan Class D/E AIP Submarine Thread

Here's a more detailed report in Chinese:

There are several other inaccuracies in the Yahoo article. The sub wasn't patrolling in an "area thousands of meters deep", the original Chinese text says the sub met a sudden change in water density, causing the sub to sink thousands of meters deep (and ostensibly thus causing the emergency). Big difference between the two meanings.

Actually, for this case, the meaning should be the same, the sub have to be sailingan area where the sea is atleast 1000m deep for it to sink 1000m in an emergency? no?

 

[solarz]

Re: PLAN Yuan Class D/E AIP Submarine Thread

Actually, for this case, the meaning should be the same, the sub have to be sailingan area where the sea is atleast 1000m deep for it to sink 1000m in an emergency? no?

Actually, JayBird is right, I was reading too quickly.

那天，该艇正执行远航巡逻任务，在数百米深的大洋潜航，遭遇海水密度突变造成的“断崖”掉深。这是潜艇水下最危险的状况之一，如果不能迅速控制下潜状态，“掉深”到极限深度便会艇毁人亡，外军潜艇曾有过血淋淋的教训。

此时，事发海域水深数千米，该艇失去浮力急速下潜，主电机舱管道因深海巨大压力而破损，海水喷涌而入……危机时刻，全艇官兵条件反射般的反应速度和指挥员果敢正确的应急处理，3分钟内,在能见度几乎为零的水雾环境中，关闭了大大小小近百个阀门和开关，操纵了几十种仪器，将险情成功化解。

It sounds like the patrol area was hundreds of meters deep, but the sub suddenly came upon a spot that was thousands of meters deep and ran into a different water density, causing it to sink rapidly.

The crew reacted quickly, closing almost a hundred valves in the space of 3 minutes, under almost zero-visibility conditions (due to water vapors).

 

[Blackstone]

Re: PLAN Yuan Class D/E AIP Submarine Thread

OUTSTANDING seamanship by the CO & crew of the 372 boat. Bravo Zulu!(Well Done)

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Great work by the skipper and crew to save the boat and their lives, and it's good to see China being more transparent with military accidents. However, it's possible this is a one-of affair and designed to maximize propaganda.

In other news, another Kilo accident? Multiple navies in the region had serious incidents involving Kilos of late, are they just co-incidents, or are Kilo subs problematic?

 

[SamuraiBlue]

Re: PLAN Yuan Class D/E AIP Submarine Thread

Here's a more detailed report in Chinese:

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No mention of "proving loyalty" anywhere. Just lots of praise about courage and training, typical military stuff.

Note that this incident actually happened back in January.

There are several other inaccuracies in the Yahoo article. The sub wasn't patrolling in an "area thousands of meters deep", the original Chinese text says the sub met a sudden change in water density, causing the sub to sink thousands of meters deep (and ostensibly thus causing the emergency). Big difference between the two meanings.

Subs don't have pressure hulls that can hold up at thousands of meters, probably be around 1,500~2,000 meters at most before the hull is crushed and the pumps to blow the ballast tanks would fail before they reach those depth.
Think about it at 2,000 meters the pressure is approx. 2900PSI.
I also have doubts about this accident being natural cause since both salinity and water temperature both variables in density of water is pretty stable below 200m.
One theory that I could think of that is plausible is that the sub was testing close to her floor operational depth and the ballast pumps failed to blow the tanks resulting to emergency procedure to raise the boat.

 

[Blitzo]

Re: PLAN Yuan Class D/E AIP Submarine Thread

Regardless of what transpired in the actual event, it says 372 is a Kilo, so wrong thread?

 

[Jeff Head]

Re: PLAN Yuan Class D/E AIP Submarine Thread

Regardless of what transpired in the actual event, it says 372 is a Kilo, so wrong thread?

Well, I looked and we did not have a thread that included the PLAN kilos...so, I added them here and updated the name accordingly.

This pretty much gets all of our bases covered for the PLAN subs now.

 

[superdog]

Re: PLAN Yuan Class D/E AIP Submarine Thread

Subs don't have pressure hulls that can hold up at thousands of meters, probably be around 1,500~2,000 meters at most before the hull is crushed and the pumps to blow the ballast tanks would fail before they reach those depth.
Think about it at 2,000 meters the pressure is approx. 2900PSI.
I also have doubts about this accident being natural cause since both salinity and water temperature both variables in density of water is pretty stable below 200m.
One theory that I could think of that is plausible is that the sub was testing close to her floor operational depth and the ballast pumps failed to blow the tanks resulting to emergency procedure to raise the boat.

According to a "Navy office observer" who was on the boat during the incident, they were patrolling at a "large depth" when they hit the density change (most likely somewhere between 200-300m). At the beginning the sub starts dropping 10m per minute. The on-shift captain first gently increased the speed and used normal procedure to increase buoyancy, but by the 4th minute they have plunged 30m and continue to drop, then they shifted to a higher power/nosier mode and prepares to blow the middle main ballast. By the 6th minute they have dropped 49m and the hull start to make grunting noises. At this time the on-shift captain ordered to blow the middle main ballast, and the boat captain has also arrived to the control room to help.

About 20 seconds later, pipes ruptured with a loud bang in compartment 5 (motor compartment), the crew there have to shut-off the motor and cut power. Upon receiving this report, the mission commander immediately ordered to blow all the main ballasts, and the on-shift captain started damage control alert. At this time the sub has lost power and continue to drop with the tail angled down, it became difficult to stand up without holding onto something.

Fortunately the 3 sailors in compartment 5 were able to quickly seal the compartment and shut off the damaged pipes before too much water came in, and pumping air into the ballasts eventually worked. The sub stopped dropping by the 8th minute after gaining 70.6m of depth. It wasn't mentioned if the sub went over its test depth (300m), it's possible if the incident started well under 200m.

After stopping the drop they did a controlled surfacing and surfaced by the 14th minute. They found that water filled about 1/8th of compartment 5 and many electrical systems were damaged. The mission commander wanted to dive before sunrise to avoid detection, but some of the crew were not very confident if they could continue on. Eventually they managed to fixed necessary equipments within 3 hours to dive again, and they continued to fix as much as they could in the next 90 hours. Despite the boat could only travel at 4 knots and could not reverse, they went on to successfully complete the mission.

 

[superdog]

Re: PLAN Yuan Class D/E AIP Submarine Thread

Exactly..Ahh... what would they do but save the boat? That is part of those shipmates job.

A lot is lost in the translation I assure you.



Perhaps this is better.....Proved they were all well trained and put that training to use in an emergency situation.

Part of it was that they handled the emergency well, especially the 3 men who sealed themselves in compartment 5.

Another part was that they did not give up the mission despite all the damage. A less dedicated crew could have given up and request assistance after surfacing from such a scare.

 

[Equation]

Re: PLAN Yuan Class D/E AIP Submarine Thread

According to a "Navy office observer" who was on the boat during the incident, they were patrolling at a "large depth" when they hit the density change (most likely somewhere between 200-300m). At the beginning the sub starts dropping 10m per minute. The on-shift captain first gently increased the speed and used normal procedure to increase buoyancy, but by the 4th minute they have plunged 30m and continue to drop, then they shifted to a higher power/nosier mode and prepares to blow the middle main ballast. By the 6th minute they have dropped 49m and the hull start to make grunting noises. At this time the on-shift captain ordered to blow the middle main ballast, and the boat captain has also arrived to the control room to help.

About 20 seconds later, pipes ruptured with a loud bang in compartment 5 (motor compartment), the crew there have to shut-off the motor and cut power. Upon receiving this report, the mission commander immediately ordered to blow all the main ballasts, and the on-shift captain started damage control alert. At this time the sub has lost power and continue to drop with the tail angled down, it became difficult to stand up without holding onto something.

Fortunately the 3 sailors in compartment 5 were able to quickly seal the compartment and shut off the damaged pipes before too much water came in, and pumping air into the ballasts eventually worked. The sub stopped dropping by the 8th minute after gaining 70.6m of depth. It wasn't mentioned if the sub went over its test depth (300m), it's possible if the incident started well under 200m.

After stopping the drop they did a controlled surfacing and surfaced by the 14th minute. They found that water filled about 1/8th of compartment 5 and many electrical systems were damaged. The mission commander wanted to dive before sunrise to avoid detection, but some of the crew were not very confident if they could continue on. Eventually they managed to fixed necessary equipments within 3 hours to dive again, and they continued to fix as much as they could in the next 90 hours. Despite the boat could only travel at 4 knots and could not reverse, they went on to successfully complete the mission.

Wow...I bet very few officers and crew members get any real sleep until they reached base. I hope they have charted that density change area on their map for future references and to avoid. Thanks for the story explanation.

 

[Janiz]

Re: PLAN Yuan Class D/E AIP Submarine Thread

According to a "Navy office observer" who was on the boat during the incident, they were patrolling at a "large depth" when they hit the density change (most likely somewhere between 200-300m).

Wow, where did you get documents from the investigation? They were made public? You post is so detailed that it looks like you took it fromthe officer's testimony. I thought that would be classified document...