Martin Cooper
Member
This is the image of the plates on the seabed.
This is the image of the plates on the seabed.
Martin Cooper
Member
It is surprising that many people still thought she had gone down in one piece, while others said she had broken in two. The theory was assumed that she had broken at the expansion joint, does this still hold, or is this there a new theory about this?
Jim Currie
Senior Member
There are so many myths about these expansion joints Martin.
Expansion joints in a ship were not fitted in the hull itself. They were found in the superstructure and in horizontal pipe runs.
The hull of a ship is much like a steel girder. The main longitudinal strength parts of the hull are the keel, the garboard strakes (fore and aft plating immediately on each side of the keel and the Sheer strake - the topmost fore and aft line of shell plating where the hull meets the main strength deck on each side. Additional girder strength is given by a double bottom. Titanic was no different.
A ship lying in still water will have lots of localised stresses acting up with buoyancy and down due to localised weights within the hull.
There's loads of evidence that Titanic's hull spilt at the surface although Lightoller did not believe it did and he was very close to it.
Personally, I think it tried to bend first. The hull should not have split because of this but because the hull was not upright and on an even keel, a twist was imposed in the 'girder' causing it to distort and tear - on one side first, then the other at deck level before the bending moment took over and it tore vertically.
A bit like trying to tear an oblong cardboard box. You'll find it's easier to tear it in the middle if you twist it first to start the tear.
This would be easiest in the accommodation structure in way of a vertical hull opening like a staircase or similar where the accommodation structures is not continuous from side to side.
It looks to me Walter that the accommodation ripped downward. Then, the rip propagated into the sheer strake on one side first then the other side. The the bigger forward part then virtually hinged down, with the weakened hull parts just aft of the double bottom acting much like a giant hinge. The stern part, would then seem to come upright before it too tipped over and was dragged down by the bigger section still attached to it by ever weakening connections. Then the whole thing came apart on the way down due to incredible stresses and strains etc. That's my 10 cents worth.
Jim
Expansion joints in a ship were not fitted in the hull itself. They were found in the superstructure and in horizontal pipe runs.
The hull of a ship is much like a steel girder. The main longitudinal strength parts of the hull are the keel, the garboard strakes (fore and aft plating immediately on each side of the keel and the Sheer strake - the topmost fore and aft line of shell plating where the hull meets the main strength deck on each side. Additional girder strength is given by a double bottom. Titanic was no different.
A ship lying in still water will have lots of localised stresses acting up with buoyancy and down due to localised weights within the hull.
There's loads of evidence that Titanic's hull spilt at the surface although Lightoller did not believe it did and he was very close to it.
Personally, I think it tried to bend first. The hull should not have split because of this but because the hull was not upright and on an even keel, a twist was imposed in the 'girder' causing it to distort and tear - on one side first, then the other at deck level before the bending moment took over and it tore vertically.
A bit like trying to tear an oblong cardboard box. You'll find it's easier to tear it in the middle if you twist it first to start the tear.
This would be easiest in the accommodation structure in way of a vertical hull opening like a staircase or similar where the accommodation structures is not continuous from side to side.
It looks to me Walter that the accommodation ripped downward. Then, the rip propagated into the sheer strake on one side first then the other side. The the bigger forward part then virtually hinged down, with the weakened hull parts just aft of the double bottom acting much like a giant hinge. The stern part, would then seem to come upright before it too tipped over and was dragged down by the bigger section still attached to it by ever weakening connections. Then the whole thing came apart on the way down due to incredible stresses and strains etc. That's my 10 cents worth.
Jim
Martin Cooper
Member
Hello Jim, Many thanks for your post, and many thanks for taking the time to explain things in such a good and understandable way (well, to a landlubber such as myself), that is a brilliant explanation.
I have read theories in books, and also seen documentaries on TV about the way it was thought that Titanic had split at one of her expansion joints, but wasn't sure if there was a new theory about this.
Your explanation of 'like a giant hinge' still being attached to the stern until (by ever weakening connections), it finally broke apart when underwater, was what I was trying to describe in the scenario, the bow section could then go down and end up pointing in a different direction than it was pointing on the surface. I wonder if when the last of these weakened connections was severed, that this is what might have made the stern turn around before sinking?
Thanks again Jim for your explanation.
Regards, Martin.
I have read theories in books, and also seen documentaries on TV about the way it was thought that Titanic had split at one of her expansion joints, but wasn't sure if there was a new theory about this.
Your explanation of 'like a giant hinge' still being attached to the stern until (by ever weakening connections), it finally broke apart when underwater, was what I was trying to describe in the scenario, the bow section could then go down and end up pointing in a different direction than it was pointing on the surface. I wonder if when the last of these weakened connections was severed, that this is what might have made the stern turn around before sinking?
Thanks again Jim for your explanation.
Regards, Martin.
Michael H. Standart
Member
>>True, but in-built false assumptions are also repeated. As I pointed out: there was a great deal of information concerning the moment when the ship went below the surface that we can never know about, therefore lack of this is the limiting factor for any test tank experiment.<<
Thus my challange remains. Show me a better test. One which accounts for the variables you mentioned so we can see what actually happens.
Thus my challange remains. Show me a better test. One which accounts for the variables you mentioned so we can see what actually happens.
Jim Currie
Senior Member
I can see your point clearly Michael and have no wish to belittle it in any way. Excuse me if it seems that way to to you.
As I see it the fault lies with the 'experts' who know better than you or me the limitations of such an experiment.
Basically, after their tank experiments, they know no more than you or me concerning what happened after Titanic disappeared from sight but went to great lengths and expense to prove it! They will, of course , have added to their knowledge concerning the sinking of that particular model and the behaviour, while sinking, of objects in general
Jim
As I see it the fault lies with the 'experts' who know better than you or me the limitations of such an experiment.
Basically, after their tank experiments, they know no more than you or me concerning what happened after Titanic disappeared from sight but went to great lengths and expense to prove it! They will, of course , have added to their knowledge concerning the sinking of that particular model and the behaviour, while sinking, of objects in general
Jim
Michael H. Standart
Member
>>Basically, after their tank experiments, they know no more than you or me concerning what happened after Titanic disappeared from sight but went to great lengths and expense to prove it!<<
Actually, they did. For example, the possibility of excessive drag because of buckled wreckage acting as something of a foil causing the bow to spiral down was effectively ruled out as a possibility?
Why?
Because they attatched some metal to the model on the starboard side...a fairly substantial piece at that...and tried it to see what would happen.
It failed to spiral down as it dropped through the water column.
Questioning the science isn't something I have a problem with. Scientists do that much all the time and a lot more often then some here may be willing to give them credit for.
Dismissing the science with nothing more to support the proposition then What If's, Whatabouts, and absolutely no supporting evidence or testing data is something I have some issues with. Regretably, that appears to be what's happening here.
Thus the challange still remains.
Show me a better test. Something which is repeatable, verifiable, demonstrerable, and which refutes the earlier test.
Actually, they did. For example, the possibility of excessive drag because of buckled wreckage acting as something of a foil causing the bow to spiral down was effectively ruled out as a possibility?
Why?
Because they attatched some metal to the model on the starboard side...a fairly substantial piece at that...and tried it to see what would happen.
It failed to spiral down as it dropped through the water column.
Questioning the science isn't something I have a problem with. Scientists do that much all the time and a lot more often then some here may be willing to give them credit for.
Dismissing the science with nothing more to support the proposition then What If's, Whatabouts, and absolutely no supporting evidence or testing data is something I have some issues with. Regretably, that appears to be what's happening here.
Thus the challange still remains.
Show me a better test. Something which is repeatable, verifiable, demonstrerable, and which refutes the earlier test.
S
Stephen Walker
Member
>>I'm not so sure I'd bet the farm on that one. The carafe which Ken Marschall photographed was pretty secure in it's holder. If you take a look at the condition of the bow, notably the way it's canted downwards from the horizontal ahead of the superstructure, and the way the mud is ploughed up around it, the impact with the bottom was pretty violent.<<
True, the carafe was sitting in a tray which kept it from moving somewhat. The big test for it of course was the impact with the seabed! The bow did indeed strike fairly hard--I think it was Dr. Ballard who estimated its impact speed in the neighborhood of 30 knots or so. I was thinking more in terms of what the bow did on the way down; it must not have ever stood on end or tilted at a 90% angle or anything of that sort for items like these to have remained in place.
On the breakup, I remember reading (I think this was Ballard's book again) that the large, open 1st Class Dining Saloon may have been a weak point in the hull when the sinking ship reached its most extreme attitude in the water. Of course Ballard is not a naval architect, but I wonder if this may have been a factor?
True, the carafe was sitting in a tray which kept it from moving somewhat. The big test for it of course was the impact with the seabed! The bow did indeed strike fairly hard--I think it was Dr. Ballard who estimated its impact speed in the neighborhood of 30 knots or so. I was thinking more in terms of what the bow did on the way down; it must not have ever stood on end or tilted at a 90% angle or anything of that sort for items like these to have remained in place.
On the breakup, I remember reading (I think this was Ballard's book again) that the large, open 1st Class Dining Saloon may have been a weak point in the hull when the sinking ship reached its most extreme attitude in the water. Of course Ballard is not a naval architect, but I wonder if this may have been a factor?
Martin Cooper
Member
Regarding the tank tests. I should think that there would be that many variables involved, that unless everything was simulated exactly, it would be almost impossible to recreate how Titanic behaved on the night she sank. Maybe the men doing the testing would all be retired and a younger generation doing the job before they got it right, but who knows, they might get lucky one day.
Michael H. Standart
Member
>>it must not have ever stood on end or tilted at a 90% angle or anything of that sort for items like these to have remained in place.<<
IF the drop tank tests are any indication, it didn't. Regardless of what can be shown, it still would have been a rough ride. One which effectively trashed the bow, and yet it left a lot of the china intact.
>>Regarding the tank tests. I should think that there would be that many variables involved, that unless everything was simulated exactly, it would be almost impossible to recreate how Titanic behaved on the night she sank.<<
Maybe, maybe not. The people who did these tests for the Discovery Channel were not amatures, but trained naval architects who knew what they were doing. Tank testing as a methodology has been around for over 160 years and has been very effective and remarkably accurate in showing how various hull forms would behave.
Captain Jim's concerns and caveats are entirely valid, and I won't shortsell that. You can't factor in every single variable since you can't possibly know what every single one is. There's always something new to be learned. However, it's been shown time and again that you can get mighty damned close, and until somebody can come along with something better which falsifies the work, I'm obliged to give provisional assent to the findings.
IF the drop tank tests are any indication, it didn't. Regardless of what can be shown, it still would have been a rough ride. One which effectively trashed the bow, and yet it left a lot of the china intact.
>>Regarding the tank tests. I should think that there would be that many variables involved, that unless everything was simulated exactly, it would be almost impossible to recreate how Titanic behaved on the night she sank.<<
Maybe, maybe not. The people who did these tests for the Discovery Channel were not amatures, but trained naval architects who knew what they were doing. Tank testing as a methodology has been around for over 160 years and has been very effective and remarkably accurate in showing how various hull forms would behave.
Captain Jim's concerns and caveats are entirely valid, and I won't shortsell that. You can't factor in every single variable since you can't possibly know what every single one is. There's always something new to be learned. However, it's been shown time and again that you can get mighty damned close, and until somebody can come along with something better which falsifies the work, I'm obliged to give provisional assent to the findings.
Jim Currie
Senior Member
Nice discussion!
One of the reasons why the crockery did not smash was because it was subjected on all surfaces to equal pressure when the shock came. As soon as it was surrounded by water, the shock had nowhere to go. The hull probably was compressed between the force of gravity acting downward and an immovable object - the sea bed.
Ancient Roman and Greek wrecks have been found with holds full of intact yet fragile
amphora. Classic example? (excuse the pun).
Jim.
One of the reasons why the crockery did not smash was because it was subjected on all surfaces to equal pressure when the shock came. As soon as it was surrounded by water, the shock had nowhere to go. The hull probably was compressed between the force of gravity acting downward and an immovable object - the sea bed.
Ancient Roman and Greek wrecks have been found with holds full of intact yet fragile
amphora. Classic example? (excuse the pun).
Jim.
Martin Cooper
Member
>>You can't factor in every single variable since you can't possibly know what every single one is. There's always something new to be learned.<<
I agree, that is exactly my point Michael.
I agree, that is exactly my point Michael.
Martin Cooper
Member
Hello Jim, Yes there have been some brilliant finds from these old shipwrecks. It is surprising the number of items that have been recovered intact after many years underwater, even where there have been some strong currents.
Michael H. Standart
Member
>>I agree, that is exactly my point Michael.<<
However, it appears as if you missed the rest of the point I'm trying to make. Acknowladging that there are unknowns and that the unknowns somehow justify a position which is not supported or justified by the evidence is a variation of the arguement from ignorance, which is a logical fallacy.
I'm still holding out for the better experiment.
However, it appears as if you missed the rest of the point I'm trying to make. Acknowladging that there are unknowns and that the unknowns somehow justify a position which is not supported or justified by the evidence is a variation of the arguement from ignorance, which is a logical fallacy.
I'm still holding out for the better experiment.
Martin Cooper
Member
Yes, there are many unknowns, and I am not trying to justify any sort of position, I am merely using a SCENARIO to ASK IF things COULD HAVE happened in a certain way. I was also saying that because there are that many unknowns involved with the sinking of the Titanic, that there would have to be many, many tank tests done to get things right, that it would be almost impossible to do, and as you rightly said, there are that many variables you can't possibly know what every single one is, and I agreed with you on that, there is no arguement, and we are all ignorant of what actually happened, because none of us were there that night.
