How the break-up occurred

Bob_Read

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I don’t know if they missed anything in their examination of the wreck. The most important thing that they missed was not being able to precisely record events as they happened and not having complete construction information for Titanic. Without that information, all they and anyone else will be able to do is speculate using very incomplete information.
 

Kyle Naber

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This is one for the all the technical experts on here.

I know that in the mid-late 1990s there was a considerable amount of investigation conducted upon the wreck that looked into the breakup but do you think they missed anything ?

Is there anything specifically about the breakup still to learned from careful investigation of the wreck or has this went as far as it can conceivably go ?
I think we’ve found as much as we can about the breakup as far as the wreckage. The biggest thing now is de-coding what we’ve observed and trying to figure out what it means.
 

Jim Currie

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The Naval Architects would have developed a set of what is known as Stength Curves for both static and dynamic conditions of the particular hull form of Titanic. From this, it would have been very easy for them to determine the stresses imposed on any unsupported length of the hull and the resulting effects thereon. The expansion joint were not part of the hull...they were on the superstructure and designed to alleviate the effect of pitching (and subsequent hogging) in a head sea.
If you look carefully at the profile plan of the ship, you will see that there is an abrupt reduction in DB height immediately forward of the engine room. The inner bottom strength in the engine room was beefed-up by the heavy bed plate carrying the twin engines.
This situation was further aggravated by the location of a vertical void space at the forward end of said engine room. It follows that the only parts holding the ship together in that area, wer the reduced height DBs, the sheer strake on both sides at the main deck, the vertical keel plate at the garboard strakes of outer bottom plating on either side of it.

The number of and location of compartments breached were known therefor it should be fairly easy for a naval architect to develop a forecast of the progress of the event.
 

ApwbD1912

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Hello, I am new here but have been reading you for years and I'd like to discuss something.

When it comes to the break-up, the V theory is usually marked as a conspiracy, but I think there are a couple of testimonies that just can't be ignored. Both of them coming from men who were at the same location, the forwarrd boat deck, when the plunge came.
Eugene Daly is one of them, and said:
"I reached a collapsible boat that was fastened to the deck by two rings. It could not be moved. During that brief time that I worked on cutting one of those ropes, the collapsible was crowded with people hanging upon the edges. The Titanic gave a lurch downward and we were in the water up to our hips. She rose again slightly, and I succeeded in cutting the second rope which held her stern. Another lurch threw this boat and myself off and away from the ship into the water."
The second one comes from William J. Mellors:
"I was swept away from where I was right against the collapsible boat, and I simply clung on for all I was worth, whilst all this was going on the ship was going under water and it seemed as if thousands of men were dragging me under with her, when suddenly, her (the forward) nose on which I was, seemed to suddenly rise from underneath the water and I and a few more that were close by cut the ropes that held the boat to the falls."

I know the V-break theory has always been discredited by physical evidences. I always thought that the "floating bow" Miss Futrelle and some other people on the boats saw was actually some debris or maybe the pulverized third funnel deck-house, but when you mix those testimonies with the ones of the people who were at the bow it makes sense. We just can't call them liars.
We have always assumed that the bow was totally flooded when it broke off, but have in mind that the ONLY access that water had to BR#4,#3,#2 and #1 was the doors located on the Scotland Road, E deck. E deck was also the lowest not watertight deck, through which water flooded F and G deck of amidships compartments. Until all those sections were completely underwater, the flooding just could not progress upwards. I personally think that the bow was quite to very little buoyant when it broke, but that was enough to make it sink more in a ___/ position, instead of V.
 
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Bill Vanek

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I really wanted to sign on to the V-break idea because my last name starts with a V, but I just couldn't do it. ;)

I don't think that there is a flooding-based reason that we can find for the bow rising again. And the more I think about it, I don't believe that the forecastle (the Kate-n-Leonardo place) came back up, because that would have been a long way to travel after having gone down at a good angle. Rather, I think that it was the front of the boat deck that was starting to go under, and then with the mayhem of the break-up, only that forward end of the boat deck rose again. With the forecastle and well decks having disappeared a while back, a woman in a lifeboat would be seeing the boat & A & B decks lighted and near the water, and after they plunged a bit and their lights went out, would see the upward re-emergence of those decks (in the dark) as being an astounding sight, and would have mis-identified it as "the bow" rising up again. It's far easier to believe that the bridge--which was just above water a minute ago--could plunge down and then resurface, than it is to believe that the forecastle--already down a long way--could have broached.

I like the way you're looking at the mystery of the 'bow' rising again. That caught my interest as well. There are several other mysteries that I'd like to hear peoples' ideas about. They are:
1. What made water rise out of the flooded bow of the ship, and pour out of the doors and windows of the boat deck?
2. What was the "blast" that threw William Mellors and Officer Lightoller away from the ship?
3. What was the mechanism for steam, smoke, solids, and sparks coming out of the stack at the time of the break-up?

Actually, I think that all 3 are related. They all have in common a sudden development of high pressure inside the ship. Up until the break-up, flooding had been slow, with the entering water slowly displacing air inside. With a failure as major as two keel plates buckling (whether inward or outward from the ship), a huge mass of water would have entered the engine room and boiler rooms 1 and 2 quite suddenly. It is doubtful that much air could escape those spaces in the direction that the water was flooding from, but instead would have to exit the ship by going up through the ship. Now, why the air didn't have numerous ways out is a mystery to me. Why wouldn't it go out the intakes at the 3rd or 4th funnels? Or up stairwells and out the doors? It appears that some of those passages got severely restricted, keeping the air in the aforementioned instantly flooding spaces from getting out faster than the water was coming in. That would build up pressure to the tune of 2 psi. That pressure is enough to raise the the water in the flooded bow by 5 feet above sea level, and could explain Mystery #1 in my list. It might also be the power source that blew Mellors and Lightoller away from being trapped against air intake gratings that just a moment beforehand were flooding downward into the ship due to the "slight plunge" that the bow had just taken; that's Mystery #2.

But Mystery #3 is hardest. What must we have in order to shoot all of that hot stuff out the stack? Well, we'd need hot stuff (hot coals in boilers) and a large volume of air flow, with no water present at that moment. Water had already quenched the fires in all of the flooded boiler rooms 3, 4, 5, and 6, if I recall the flooding models correctly. The single-ended boilers had not been lighted; they were cold iron, according to one coal trimmer's testimony. The only boilers that could have had any hot coals still in their bellies would have been the double-ended boilers of boiler room 2. It's easy to imagine a whole lot of air rushing in through the dampers, scouring all of the coals on through the boiler tubes, up the uptakes, and out the stack, turning them into sparks and lumps of stuff being ejected. But it's not easy to understand how the air would do that before the water got there and quenched it all. Those fires were at the bottom of the compartment, and would have quickly flooded; and my previous pondering applies: why would the air go through the boilers and up the stack, and not out easier places? Maybe it was "all of the above", and it went out everywhere, including through the boiler. And maybe the boiler flooded 2 seconds after the air blew its coals upward. Anyway, someone would have to know the details of the boiler design to figure out how the air could blast through even as the water was instantly filling the compartment. Suffice it to say that there would have to be a lot of conditions met in order to do all of this.

Speaking of multiple conditions needed at the boilers: I've worked in a refinery and in chemical plants around a lot of fired heaters. Their Burner Management Systems are safety systems to prevent an explosion. Boiler explosions were common a hundred years ago, even as the National Board of Boiler and Pressure Vessel Inspectors was taking control of the situation--and doing such a good job of it that we rarely hear of such explosions today. But back in the days of apartment buildings and hotels with hot-water boilers in the basements, and steam locomotives and steamships, boiler explosions were well-known. That's why so many people on the Titanic went immediately to that as their explanation for the loud noises they heard, and called them "explosions". Now, any fired heater is hazardous when it loses feed flow (in a refinery, that's the oil that we're boiling; in a chemical plant, it's some chemical or heat-transfer fluid that we're heating; and in a locomotive or ship boiler, it's feedwater that we're turning to steam). If you lose that flow, you begin to lose your heat sink. If your fire keeps putting out heat, the fluid contents that are still present steadily carry away all the heat they can...and then that heat-transfer mechanism stops, and the thermal build-up increases. And then if you re-establish the flow that you've lost, the first flow entering instantly absorbs a lot of that heat, and boils, and makes a high-pressure volume that cannot get out quickly enough (whether out the piping, the exhaust, or a safety relief valve), and the boiler blows open from that pressure. In a locomotive or ship boiler, it can be called a "steam explosion". So the mechanism is that you must have plenty of heat, lose feed flow, and then accidentally re-establish feed flow in the right quantity to cause a lot of steam to form. Note that a trickle of water would not be enough. Note also that water level rising due to flooding would quench the fire before rising up to the hot tubes above, so it is far from certain that a steam explosion would occur. The bottom line is that it would be quite a trick to explode one of the Titanic's boilers due to flooding. The ship's lights were still on, so that meant electric power being generated, which meant steam, which meant feedwater was flowing to the hot boilers; there was no loss of flow yet. The simplistic survivor statement, 'I guess the floodwater got to a hot boiler, and it exploded' is a one-in-a-hundred chance; the flooding situation could more likely split open a boiler (hot shell suddenly cooled in one place), but flooding has quite a low chance of causing an explosion itself. Also note that none of the 10 visible boilers on the ocean floor are exploded (nor imploded, either).

Food for thought.
 
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Jim Currie

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The V break is not a conspiracy, Bill. If we carefully examine the evidence of eyewitnesses and know the main strength parts of the ship. we can build a minds-eye picture of what happened.
First: a ship is designed like a girder with a top and bottom flange. The top "flange" is the heavy strake (line ) of shell plating, which in the case of Titanic ran from bow to stern at the deck-edge of Deck C. it is called the "sheer strake"
The bottom "flange" was a little more complicated. it consists of the vertical plate keel the plate on top of the keel, the plate on the bottom of the keel and the two bottom shell plates (Garboard strakes) running from bow to stern on each side of the keel. Do you visualise this?

When a ship's stern rises out of the water.... even by a small amount, the bow dips and a stress called the "hogging stress" is imposed on a point on the upper edge of the sheet strake...the top edge of the plate is in huge tension. Consequently, the bottom "flange" is in compression.
If the tension on the upper edge of the sheer strake is great enough, it will break violently and vertically at the point of greatest stress...and usually with a very loud "BANG".
However, if the ship is up right, without a list to port or starboard, the hogging stress is shared equally between the port and starboard top edges of the sheer strake and the plates will stay intact much longer...perhaps even long enough for the ship to sink intact.
Now imagine what would happen if the ship was not only tipped by the bow but heeled over to port.
I suggest to you that in this case, the greatest stress would be on the upper edge of the starboard side sheer strake and it would part with a loud BANG. This would immediately transfer the load to the port side sheer strake and at the same time, allow a massive volume of sea water to enter the hull as the starboard side break propagated downward.
Thus, the sequence of events would be:
1...Starboard side sheer strake breaks and the hull cracks vertically downward at the break location allowing huge volumes of sea water to enter the compartments in way.
2... Ship sinks faster and port side heels even more to port imposing full stress on the port side sheer strake which then breaks with a BANG
3.... The sudden added weight in the area of the forward end of the engine room causes the bottom "girder to fail in 2 places and a sectio of the Double bottom tears free from the hull... The hull is now in two parts...the aft part returns to the upright position while the forward part continues to heel to the left and spirals bow downward toward the sea bed.

To answer you questions:

There was most certainly a V break but the Expansion Joints played no part in the main hull failure.
When the bow started down ward it did so with a forward as well as down ward movement, this gave the impression of a wave passing along the boat deck from bow toward the stern.
When the internal parts of the hull were suddenly inundates at the moment of initial failure, the flood water displace air trapped inside the compartments being flooded. In the case of the engine rooms and boiler rooms the sudden escape of trapped air through ventilator shafts would expel anything in the way such as soot, coal or Lightoller and Colonel Gracie.
The antics of the forward section as it broke loose and rolled would also confuse thos looking in the direction of the funnels visible above the surface.

Just a few thoughts.
 
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Mar 22, 2003
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V-break theory? Two views of what could be considered a V break: A break that looks like the letter \/ or a break that looks like an inverted letter /\.

So which one?
Jim's description appears to be /\ caused by hogging stress failure. (I happen to agree with this view.)
The other V break would be a sagging stress failure in the double bottom and look like \/. (I see no physical reason why this would happen.)
 
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Bill Vanek

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The V break is not a conspiracy, Bill. If we carefully examine the evidence of eyewitnesses and know the main strength parts of the ship. we can build a minds-eye picture of what happened.
First: a ship is designed like a girder with a top and bottom flange. The top "flange" is the heavy strake (line ) of shell plating, which in the case of Titanic ran from bow to stern at the deck-edge of Deck C. it is called the "sheer strake"
The bottom "flange" was a little more complicated. it consists of the vertical plate keel the plate on top of the keel, the plate on the bottom of the keel and the two bottom shell plates (Garboard strakes) running from bow to stern on each side of the keel. Do you visualise this?

When a ship's stern rises out of the water.... even by a small amount, the bow dips and a stress called the "hogging stress" is imposed on a point on the upper edge of the sheet strake...the top edge of the plate is in huge tension. Consequently, the bottom "flange" is in compression.
If the tension on the upper edge of the sheer strake is great enough, it will break violently and vertically at the point of greatest stress...and usually with a very loud "BANG".
However, if the ship is up right, without a list to port or starboard, the hogging stress is shared equally between the port and starboard top edges of the sheer strake and the plates will stay intact much longer...perhaps even long enough for the ship to sink intact.
Now imagine what would happen if the ship was not only tipped by the bow but heeled over to port.
I suggest to you that in this case, the greatest stress would be on the upper edge of the starboard side sheer strake and it would part with a loud BANG. This would immediately transfer the load to the port side sheer strake and at the same time, allow a massive volume of sea water to enter the hull as the starboard side break propagated downward.
Thus, the sequence of events would be:
1...Starboard side sheer strake breaks and the hull cracks vertically downward at the break location allowing huge volumes of sea water to enter the compartments in way.
2... Ship sinks faster and port side heels even more to port imposing full stress on the port side sheer strake which then breaks with a BANG
3.... The sudden added weight in the area of the forward end of the engine room causes the bottom "girder to fail in 2 places and a sectio of the Double bottom tears free from the hull... The hull is now in two parts...the aft part returns to the upright position while the forward part continues to heel to the left and spirals bow downward toward the sea bed.

To answer you questions:

There was most certainly a V break but the Expansion Joints played no part in the main hull failure.
When the bow started down ward it did so with a forward as well as down ward movement, this gave the impression of a wave passing along the boat deck from bow toward the stern.
When the internal parts of the hull were suddenly inundates at the moment of initial failure, the flood water displace air trapped inside the compartments being flooded. In the case of the engine rooms and boiler rooms the sudden escape of trapped air through ventilator shafts would expel anything in the way such as soot, coal or Lightoller and Colonel Gracie.
The antics of the forward section as it broke loose and rolled would also confuse thos looking in the direction of the funnels visible above the surface.

Just a few thoughts.
I'm unsure why you're counselling me on the topics of a conspiracy theory and an expansion joint. I didn't talk about either of them. You must be thinking of the person ApwbD1912, who posted before me.

I understand the construction of the ship, and how structures fail.

In your rendition of events, it isn't clear why the keel broke into pieces and tore free from the hull. Water in the engine room would not do that. Flooding into a ship compartment below sea level simply equalizes that part of the ship with the sea around it. Flooding takes away buoyancy, leaving the dead weight of the iron. The iron there could support itself and more. Maybe you're saying that the top-down break went all the way down to and through the keel?

Also, I wish that people would clarify when they are talking about a "V" break. Is it the shape of the opening that forms, or the shape of the ship once it breaks? From descriptions that people have given, it usually sounded as if they were talking about the shape of the ship: bow up, stern up, and down in the middle, like a V. Your description sounded the opposite.
 

Kyle Naber

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The “V” describes the position of the bow and stern, not the shape of the opening of the break. If the latter was the case, this theory would have more leverage in my opinion.
 

Jim Currie

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V-break theory? Two views of what could be considered a V break: A break that looks like the letter \/ or a break that looks like an inverted letter /\.

So which one?
Jim's description appears to be /\ caused by hogging stress failure. (I happen to agree with this view.)
The other V break would be a sagging stress failure in the double bottom and look like \/. (I see no physical reason why this would happen.)
This is how I see the first part of the hull failure sequence, Sam...a wee bit inaccurate but i'm sure you will see what i'm getting at.
initial failure.jpg

I'm unsure why you're counselling me on the topics of a conspiracy theory and an expansion joint. I didn't talk about either of them. You must be thinking of the person ApwbD1912, who posted before me.

I understand the construction of the ship, and how structures fail.

In your rendition of events, it isn't clear why the keel broke into pieces and tore free from the hull. Water in the engine room would not do that. Flooding into a ship compartment below sea level simply equalizes that part of the ship with the sea around it. Flooding takes away buoyancy, leaving the dead weight of the iron. The iron there could support itself and more. Maybe you're saying that the top-down break went all the way down to and through the keel?

Also, I wish that people would clarify when they are talking about a "V" break. Is it the shape of the opening that forms, or the shape of the ship once it breaks? From descriptions that people have given, it usually sounded as if they were talking about the shape of the ship: bow up, stern up, and down in the middle, like a V. Your description sounded the opposite.
Probably right about mixing-up postings.
As to the effect on the DB area forward of the engine room...When the sudden inundation took place, the ship would change her attitude in the water. Down-flooding adds extra weight... extra weight which cannot be absorbed in the normal way by even bodily sinkage will exert additional stresses onto the hull girder, if these stress are concentrated at a weak point in the structure, it will fail. If, as I suggest, the "V" break at the starboard side was the first part of a sequence of hull structural failure, then it is not difficult to imagine the process thereafter.
At the moment of first break, the starboard side of the hull which is in both longitudinal and top-vertical tension, changes its underwater attitude. The starboard side forward and aft of the initial fracture is increasingly free to move away from the point of fracture as it propagates downward...opening-up the ship's insides to the sea and forming an ever-widening vertical V. While this is going on, the port side is still intact . Increasing extra weight enters the hull forward and aft of the break. This causes sinkage but now the hull is hinged two planes...vertical, due to the increasing hogging action and transverse , due to the opening up vertical fracture. as this happens, the double bottom on the starboard side is subject to a tearing away to port action and a severe tension stress to the plate floors forward of the engine room...a point where the DB height was reduced. So on and so on... Think of the part forward of the break as a door opening and twisting off its bottom hinge. Very quickly after that, the top "hinge" failed, the bottom "hinge" fell free of the hull and the "door" spiraled down to the sea bed. The "door post" (stern section) reacted to the parting action and came upright before it too fell, spinning to the sea bed.
That's my tuppence worth. if you have anything to add to subtract... every little bit helps.
 

Bill Vanek

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Okay, I see what you're saying. You're pointing out a top-down break, followed by a side-to-side tearing of the keel--from starboard to port. You're also referring to the "V" shape as applied to the shape of the break ("The starboard side forward and aft of the initial fracture is increasingly free to move away from the point of fracture...forming an ever-widening vertical V" is how you describe it). Everyone else on this site appears to be using the "V" to mean the shape of the ship.

As I said before, flooding in the engine room and boiler room 1 is not "adding weight" in a concentrated fashion, any more than it was doing so in all of the compartments forward, which were already flooded. (None of them broke due to "weight" of the water inside, right?) Water coming in simply takes away buoyancy, equalizing the pressure of the inside of the hull to the pressure outside of it. A flooded compartment actually has less stress on it. For example, when the wreck of the submarine USS Scorpion was found, all compartments were destroyed (due to implosion) except the forward torpedo room, which had its hatches open. Experts surmised that a torpedo casualty blew open the hatches, and of course killed everyone in the compartment so that there was nobody to shut the hatch. Enough additional flooding of the operations compartment was enough to send the sub downward to the depths, where the pressure instantly crushed each air-filled compartment (including the ops compartment) one at a time. The torpedo room was equalized with the ocean; all stress was off of it. It was dead weight. That is also why the flooded portion of bow half of the Titanic is in such good shape on the ocean floor.

I still think that there was a top-down failure at the same time as a keel buckling failure. I think that there had to have been both, for a few reasons. (1) Deckhouse debris and the two keel pieces are together, and sitting in the direction that the ship had been coming from. Top and bottom pieces being together says something. I haven't heard a reasonable alternative explanation yet. (2) At the moment that there was excessive tensile stress at the top of the ship, there was also compressive stress at the keel (simple beam bending). A double bottom 5 feet thick, containing all of those beams and plating, would not compress more than a few inches; it was quite a rigid set-up. An immense compression would not (and did not) smash/crush/mangle the keel pieces smaller as their failure mode. The only way that the keel structure could fail under such a huge compressive stress state is to buckle, which amounts to part of the structure 'jumping suddenly out of the way'. (3) There was apparently an instantaneous, huge flooding event that increased the pressure in the ship at that time--different from all the previous flooding. I don't think that top-down cracking could cause that. However, I'll concede that a wholesale shattering of the side of the hull (after bulging excessively) below the waterline could do so. But such bulging and shattering was not possible with the keel intact--but would be quite expected once two keel pieces got thrown out of the way. (4) There had to arise some kind of driving force to make the ship thrust forward and momentarily bob upward at the bridge. If only a top crack snapped open, there would be equal and opposite reaction movements on each side of the split, and if the bottom (keel) stayed the same length (or merely cracked), it would add no asymmetric force to the ship's gross movement one way or the other. All of the top-down-only scenarios are pretty symmetrical fore to aft. By contrast, if the keel buckled at the same time as the top parts split, it would allow for the conversion of some of the stern's potential energy into some kinetic energy moving forward, due to a pivoting action. (To use your door analogy, picture a very heavy 3-hinge door having its top and bottom hinge pins pulled, so that when you opened the door, both the top and bottom came free at the same time. It would pivot about its center hinge until it ran out of room to move by hitting the floor.) Back to the ship. That additional stern force on the bow might have doubled the speed of the (maybe 1.5-knot?) Southwest drift that the ship probably already had. The ship moved about 1600 feet (almost 2 ship lengths) from the time of the deckhouse debris and keel pieces dropping, to the location of the 5 boilers and first engine cylinder dropping. A velocity of 3 knots would cause the ship to go that distance in 5 minutes. Besides any continued inertial drifting after "All Stop", the only "power source" for moving the ship that far in such a short time was the energy of the break-up. I think that there had to be an unbalanced forward-applied force in the mix.
 

Bill Vanek

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Do we know which sides of the boat deck those who claimed that it rose were situated?
If you're asking about witnesses in the lifeboats, I don't know that level of detail. I will say that it was a few women, and the women's testimonies are mostly rubbish because they were clueless about ships, sea life, etc. It is the men's testimonies that I rely more upon...although some of them are pretty bad, too. "Consider the source" is a good thumbrule for listening to people's testimonies.

I do know that the guys who were trying to get the collapsible lifeboats going mentioned that the bow went under, started forward, and then seemed to rise again, enabling the men to finish getting the lifeboat's fastenings cut loose. Also, men on the starboard side like R. Norris Williams had the #1 funnel fall at them; he escaped narrowly, but his father was killed by it. That's the little bit of port-vs.-starboard stuff that I know from that moment. Usually all of the testimony from that time is about water ("it washed me off" or "I jumped"), so there was not a lot of talk about the angle of the ship at that instant.
 
Mar 22, 2003
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A flooded compartment actually has less stress on it.
If you're talking about net pressure acting on the hull, that it true. But if you look at the bending moments on the hull girder, the flooded compartments would create increased stresses on the sheer strake, the same as if weight was added to those flooded compartments equal to the volume water that flooded in. And that can easily be proved.
 
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Bill Vanek

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If you're talking about net pressure acting on the hull, that it true. But if you look at the bending moments on the hull girder, the flooded compartments would create increased stresses on the sheer strake, the same as if weight was added to those flooded compartments equal to the volume water that flooded in. And that can easily be proved.
Above sea level, yes. Below sea level, no. Below sea level, water entering the ship does not add weight; it simply equalizes with the surrounding water.
 

Kyle Naber

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If you're asking about witnesses in the lifeboats, I don't know that level of detail. I will say that it was a few women, and the women's testimonies are mostly rubbish because they were clueless about ships, sea life, etc. It is the men's testimonies that I rely more upon...although some of them are pretty bad, too. "Consider the source" is a good thumbrule for listening to people's testimonies.

I do know that the guys who were trying to get the collapsible lifeboats going mentioned that the bow went under, started forward, and then seemed to rise again, enabling the men to finish getting the lifeboat's fastenings cut loose. Also, men on the starboard side like R. Norris Williams had the #1 funnel fall at them; he escaped narrowly, but his father was killed by it. That's the little bit of port-vs.-starboard stuff that I know from that moment. Usually all of the testimony from that time is about water ("it washed me off" or "I jumped"), so there was not a lot of talk about the angle of the ship at that instant.
I’m almost certain that those on the ship who talked about the deck rising were on the starboard side. If the rising sensation was only felt by those on the starboard side, is it safe to formulate the idea that the port list was simply worsening, causing the starboard side (which was partially under water) to lift up before sinking again?
 

Jim Currie

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Funchal. Madeira
Okay, I see what you're saying. You're pointing out a top-down break, followed by a side-to-side tearing of the keel--from starboard to port. You're also referring to the "V" shape as applied to the shape of the break ("The starboard side forward and aft of the initial fracture is increasingly free to move away from the point of fracture...forming an ever-widening vertical V" is how you describe it). Everyone else on this site appears to be using the "V" to mean the shape of the ship.

As I said before, flooding in the engine room and boiler room 1 is not "adding weight" in a concentrated fashion, any more than it was doing so in all of the compartments forward, which were already flooded. (None of them broke due to "weight" of the water inside, right?) Water coming in simply takes away buoyancy, equalizing the pressure of the inside of the hull to the pressure outside of it. A flooded compartment actually has less stress on it. For example, when the wreck of the submarine USS Scorpion was found, all compartments were destroyed (due to implosion) except the forward torpedo room, which had its hatches open. Experts surmised that a torpedo casualty blew open the hatches, and of course killed everyone in the compartment so that there was nobody to shut the hatch. Enough additional flooding of the operations compartment was enough to send the sub downward to the depths, where the pressure instantly crushed each air-filled compartment (including the ops compartment) one at a time. The torpedo room was equalized with the ocean; all stress was off of it. It was dead weight. That is also why the flooded portion of bow half of the Titanic is in such good shape on the ocean floor.

I still think that there was a top-down failure at the same time as a keel buckling failure. I think that there had to have been both, for a few reasons. (1) Deckhouse debris and the two keel pieces are together, and sitting in the direction that the ship had been coming from. Top and bottom pieces being together says something. I haven't heard a reasonable alternative explanation yet. (2) At the moment that there was excessive tensile stress at the top of the ship, there was also compressive stress at the keel (simple beam bending). A double bottom 5 feet thick, containing all of those beams and plating, would not compress more than a few inches; it was quite a rigid set-up. An immense compression would not (and did not) smash/crush/mangle the keel pieces smaller as their failure mode. The only way that the keel structure could fail under such a huge compressive stress state is to buckle, which amounts to part of the structure 'jumping suddenly out of the way'. (3) There was apparently an instantaneous, huge flooding event that increased the pressure in the ship at that time--different from all the previous flooding. I don't think that top-down cracking could cause that. However, I'll concede that a wholesale shattering of the side of the hull (after bulging excessively) below the waterline could do so. But such bulging and shattering was not possible with the keel intact--but would be quite expected once two keel pieces got thrown out of the way. (4) There had to arise some kind of driving force to make the ship thrust forward and momentarily bob upward at the bridge. If only a top crack snapped open, there would be equal and opposite reaction movements on each side of the split, and if the bottom (keel) stayed the same length (or merely cracked), it would add no asymmetric force to the ship's gross movement one way or the other. All of the top-down-only scenarios are pretty symmetrical fore to aft. By contrast, if the keel buckled at the same time as the top parts split, it would allow for the conversion of some of the stern's potential energy into some kinetic energy moving forward, due to a pivoting action. (To use your door analogy, picture a very heavy 3-hinge door having its top and bottom hinge pins pulled, so that when you opened the door, both the top and bottom came free at the same time. It would pivot about its center hinge until it ran out of room to move by hitting the floor.) Back to the ship. That additional stern force on the bow might have doubled the speed of the (maybe 1.5-knot?) Southwest drift that the ship probably already had. The ship moved about 1600 feet (almost 2 ship lengths) from the time of the deckhouse debris and keel pieces dropping, to the location of the 5 boilers and first engine cylinder dropping. A velocity of 3 knots would cause the ship to go that distance in 5 minutes. Besides any continued inertial drifting after "All Stop", the only "power source" for moving the ship that far in such a short time was the energy of the break-up. I think that there had to be an unbalanced forward-applied force in the mix.
The forward flooding was controlled. in that it entered the hull between water tight bulkheads. These kept it confined to one side of each space between these bulkheads.. The rate of flooding in each space was directly related to the size of the hull breech. However, unlike sudden vertical opening in the hull, it was not catastrophic. Nor was it "added weight". it was a loss of buoyancy. There is a difference. You can add weight to a ship until she reaches her Margin Line and she will remain afloat. Normally, weight is added to a vessel in a very controlled manner
Have a look at the profile plan of the ship on this site and note the enormous vertical void immediately aft of WT Bulkhead "K"... the forward main engine room bulkhead. Now imagine the forces at work when thousands of tons of sea water are suddenly loaded into that space... not flooded as when a compartment is bilged.
 
Mar 22, 2003
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The loss of buoyancy is the exactly same as the added weight of water that enters a compartment. It's just another way of looking at things. Adding 10,000 tons of water to a compartment say by pumping it in through a hose produces the exact same result as letting 10,000 tons of water flood the compartment through an opening in the hull. The vessel will trim down to the exact same configuration.
 

Jim Currie

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Apr 16, 2008
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Funchal. Madeira
The loss of buoyancy is the exactly same as the added weight of water that enters a compartment. It's just another way of looking at things. Adding 10,000 tons of water to a compartment say by pumping it in through a hose produces the exact same result as letting 10,000 tons of water flood the compartment through an opening in the hull. The vessel will trim down to the exact same configuration.
That is technically true, but In Naval Architecture, and ship stability considerations, they are treated in a different way.
Loss of bouyancy has to be controlled, added weight is made in a controlled manner while constantly considering the navigability of the vessel. If you had been trained in Naval Architecture you would know this