Didn't they bring up some of ss Persia from 10,000ft down? I guess little Explorer will remian where she is until in 50 years time someone writes a book claiming she went down with some precious cargo aboard or other conspiracy theory

That link made very interesting reading.

Lets hope if she does return for another trip she has no problems.

Article

And his EXCELLENT Photo Log:

quote:

---

Originally posted by sread:
An excellent narrative of Explorer's demise.

A question. In the caption to this picture it says the ship's righting angle will soon be reached and over she'll go. The ship looks like she's already over by almost 90 degrees. How far over can they go?

---

Be careful, it does NOT say that. It says the the righting curve will go negative. This means that there will not be an uprighting torque anymore at all - the ship will flip over as the ship will not counteract any heeling torque anymore - the torque that usually is moving a ship 'backwards' to an upright position is then acting WITH the heeling torque - so it will flip over 'on it's own' or due even a minor disturbance.

This is different to increasing the heeling angle of a ship (being intact or damaged) until the uprighting torque is vanishing or becoming a capsizing torque. (Here is a nice article on ships stability - where you BTW can learn from which angles a typical ship is coming back to an upright position) In this case the ship would 'come back' (also a damaged ship) until a certain maximum angle is reached - you would have to 'push it' over this angle to capsize it.

Don't confuse that with the heeling a ship goes trough when being flooded. If the flooding is slow the ship goes through various equilibrium positions until there is no uprighting torque anymore. Also damaged ships can roll - they come back from small heeling angles - of course not back to their undamaged floating condition but back to e.g. an inclined but still stable floating condition.

[ 12-04-2007: Message edited by: Ernst ]

What caused the EXPLORER to be lost was her fatal heeling over and resultant uncontained progressive internal flooding. There are two causes for a ship to take a dramatic heel. One is offcenter weights such as shifting cargo or assymetrical internal flooding (which is what I believed caused the EXPLORER to list so dramatically). The other cause is for a vessel to lose her initial stability and then flop over to one side. This happens when weights are raised to high in the ship or when you have loose flooding inside the hull called "free surface" the effect of which is very detrimental. If you have assymetrical internal flooding, to save the ship, it is critical to seal the hull breach, to counterflood (if possible) to bring the ship upright and then press the compartment to 100% full you do not have free surface and the while you loose bouyancy and brings the ship dangerously low in the water, the effect will keep the ship afloat.

IMO, loose water inside the hull and offcenter weight caused EXPLORER to heel to the point where her deck edge when under and as water found more and more points to gain access into the ship, the heel increased, the stability decreased and the flooding eventually spread uncontrolled throughout the vessel until she most likely lay over on her side until her hull simply vanished beneath the surface, but I do not thing there is an actual witnessing of her sinking.

If and only if the hole could have been plugged early, then the EXPLORER might have been saved. However it is usually only government ships which carry damage control equipment able to seal a serious hull breach and have the trained personnel to take those emergency measures in the first hours when those measures are most effective. Sadly, commercial vessels just don’t have either but in remote and hazardous waters such as in Antarctica, having very substantial damage control ability should be every bit as important as firefighting or lifesaving abilities.

[ 12-04-2007: Message edited by: Marlowe ]

quote:

---

Originally posted by Marlowe:
[...]
What caused the EXPLORER to be lost was her fatal heeling over. [...]

---

One must not confuse heeling an (intact) ship beyond the angle where the uprighting torque would not counteract the inclining torque anymore with the heel causes due to e.g. unsymmetrical flooding.

Explorer did not sink because she heeled too much but heeled because she sprung leak. She has NOT been 'knocked over' beyond the 'angle of no return'.

The stability curve of the ship changes while being flooded. Looking at e.g. the maximum angle the intact ship can recover from has nothing to do with the maximum angle a ship can stay afloat due to e.g. flooding (parts of) the hull.

(And as said, damaged ships can be stable - some ships are even more stable when partially flooded)

quote:

---

Originally posted by Marlowe:
[...]
The other cause is for a vessel to lose her initial stability and then flop over to one side. This happens when weights are raised to high in the ship or when you have loose flooding inside the hull called "free surface" the effect of which is very detrimental.[...]

---

Well, it is pretty certain that the center of gravity of Explorer has not been raised while she sank.

I also doubt that the formation of free surfaces in the hull during the flooding played too much of a role in this case. (this was not the reason why she went down - she has not been 'knocked over' by the water rushing from one side to the other in her hull - not before she has been flooded too excessively anyhow)
As it appears now Explorer sank because she was slowly flooded.

[ 12-04-2007: Message edited by: Ernst ]

quote:

---

Originally posted by Marlowe:

If and only if the hole could have been plugged early, then the EXPLORER might have been saved. However it is usually only government ships which carry damage control equipment able to seal a serious hull breach and have the trained personnel to take those emergency measures in the first hours when those measures are most effective.
[ 12-04-2007: Message edited by: Marlowe ]

---

Ernst and Marlow, kudos on a great discussion from which I learn from

I understand that in 2002 abouts the QE2 popped a sea chest and she started to flood. With the courage of the fearless crew they used a compressed air bladder to plug the hole and the ship safely made it to port where permanent repairs were made.

Could the air bladder machine plugged the fist size hole of the explorer? Why did they not have the equipment?

It is very likely that the damage was more excessive than one fist size hole. We will see.

[ 12-04-2007: Message edited by: Ernst ]

quote:

---

Originally posted by desirod7:

With the courage of the fearless crew

---

...the QE2 would be lost, the QE2 would be lost.

I am not trying to start an argument with you over this but I must first say that the correct term is "righting moment" not torque and what I said was that the EXPLORER was not lost due to loss of righting moment (stability) but from assymetrical flooding which started a list which gradually kept increasing until the deck edge went under and at that point the ship was lost. Flooding without a list gives much more time before the deck is immersed. Had the flooding been checked before that critical point of the rail dipping under then it is just possible that the ship could have been prevented from sinking. That of course brings in the issue of what do you do with a badly disabled vessel in the Antarctic? No drydocks there and I doubt many vessels could make the tow across the Drake Passage and live to tell the tale.

I recall vaugely the QE2 flooding incident was a inlet pipe coming from a seachest fractured and that the engineers were able to push something inflatable into the pipe and once blown up gave the engineers to pour a cement patch around the ruptured pipe. Whether the balloon was part of the ship's damage control kit or not is a point I do not remember. Regardless of whether is was or if it was something "jury rigged" in the moment, it saved the ship from some serious flooding.

Regarding the conjecture that the water ingress was in a passenger cabin to me seems highly unlikely unless the EXPLORER has passenger cabins below the waterline. I would think that it might have been a crew stateroom.

Whether such a device would have worked to stop the ingress of water into the EXPLORER is something I cannot see. Generally a hull breach any depth below the waterline involves water coming in under tremendous pressure and even a 4" diameter hole 10' below the level of the outside sea causes 993 gallons per minute to enter the hull. For a hull breach small enought to allow it, the best thing to to try to rig some kind of external patch which then is held in place with lines quite possible running under the hull. I know matresses have been used successfully for this. After the external patch is in place, there are many techniques to internally seal the breach.

It is very likely that Explorer sank because more than one compartment was flooded (assuming that everything was as it should be) - and this would have caused her to sink also with symmetrical flooding. (Flooding only one compartment should have never caused her to heel that far that the margin line is submerged - even if this compartment is flooded unsymmetrically)

[ 12-05-2007: Message edited by: Ernst ]

quote:

---

Originally posted by Eric:
Extract from a 1st person account by someone in one of the original affected cabins, posted on CC board

"Why did the boat sink? While it is true that there was a hole in the hull, the water tight doors were shut. The compartment where our cabin was should have filled up with water, but the boat should have continued to float. My understanding was that the problem was with the toilets. The water went into the toilets and then into the holding tank. When the holding tank filled up the water backed up into the other cabins thus bypassing the watertight doors"
Eric

---