Shallow Angle Break Theory

Re: Shallow Angle Break Theory

Postby Jeremy Aufderheide on Thu Apr 12, 2012 8:27 am

Some probably did it to protect WSL's reputation in how they built ships that saying the ship break in half may hurt WHL

How would saying that a ship broke up as it sank hurt the WSL? They built them to float in one piece, not sink in one piece. It's not like the public is going to say, "Well, I'm not sailing on a White Star ship because they break in two when they sink."

How a ship behaves on the surface and how a ship behaves while sinking are two different things.
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Re: Shallow Angle Break Theory

Postby Jim Buchanan on Thu Apr 12, 2012 4:19 pm

I agree with you Jeremy.

There is one bit of evidence concerning the angle of the ship during the sinking which seems to have escaped most people's attention. I refer to the evidence of Mr. Wilder, The H&W Naval Architect who gave evidence at the UK Inquiry.

"The Witness:[Mr/ Wilder]
Yes, that is what I wanted to say. It was done to make the calculation a practicable one. I then flooded No. 5 boiler room in identically the same way as I had previously flooded No. 6, adding its flooding effect to the forward spaces, and I got the black line, which, as you will notice, puts the forecastle entirely under water, and also the forward end of forward deck, B deck, which is the top deck shown on these elevations. That means that the waterline is something like that (Describing with a pointer on the model.)

Mr. Rowlatt:
He is showing your Lordship on the model approximately how it would be when No. 5 was also flooded.

The Witness:
That is right; about where we got the long tube, My Lord.

20341. Then if it went into No. 4 also, is that shown to be red hatched?
- Yes. In order to understand effect of the red hatching and to see what it really means, it is best to tilt the plan and put it like this, so that the red line is approximately parallel to the forecastle head, and it shows that the stern is out of the water as far about as the base of the mainmast, or a little further forward."

If you look at a side view of Titanic, you will see that when No.5 boiler room became flooded , the stern would then be about 8 degrees to the sea level and about 15' out of the water.

Consider the evidence of Trimmer Dillon. he said he was ordered out of boiler room 4 when it started showing signs of taking in water. That was at about 1:15am. Ten minutes later he was on deck in time to find out that the last proper lifeboat was about to leave. That would be about 1:25am.

Now number 4 boiler room would be filling. However, since the aft bulkhead of number 4 would be near the center of flotation (around whuch the ship would pivot fore and aft) more of the flood water would be causing the ship to sink bodily rather than causing her to tip by the head. Consequently the angle berween the stern and the sea would not increase by much more. So what caused the ship to break where she did?

Perhaps this was the reason for Wilding's response to the suggestion that the ship broke her back at the surface?

"20258. We have heard something in the evidence about an apparent fracture of the whole ship as she foundered, which is rather why I was going a little minutely into this part of it. Do you believe that happened?
- Not in the least. I have tried to make an approximate calculation, and I feel quite sure it did not happen.

20259. That is why I was asking you - of course I will not ask it more than is thought material - as to the strength of its construction. As I understand, the whole of the ship is, as you explained to us yesterday, a girder?
- Yes.


James.
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Re: Shallow Angle Break Theory

Postby Joshua Noble on Thu Apr 12, 2012 9:02 pm

One thing that might help is Lightoller said the crow's nest was just above the water when the Boat Deck went under and he was swimming away from the ship. This tells me that the ship had a steeper angle than the theory being discussed proposes.
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Re: Shallow Angle Break Theory

Postby Jim Buchanan on Fri Apr 13, 2012 2:15 pm

I have just had another look at my plans and applied the evidence of Mr. Wilder and QM Rowe to them.

Titanic did not raise her stern much more than 6 degrees before she sank. here's why:

The ship's stern was 12 feet 8 inches out of the water and she was 4 degrees down by the head when the water line was from the forward end of the forecastle head (fore end of deck 'B') to the top of the bulkhead between boiler room 5 and boiler room 4. That was just before it spilled over into boiler room 4. This would be about 1:15am according to Trimmer Dillon.
Also according to him, the last real lifeboat boat would leave about 15 minutes later at 1:30am so the trim by the head was not all that significant at that time either.

According to QM Rowe, he left Titanic on collapsible boat C. At the time, he noted that the forward well-deck.. deck C was awash. In other words Titanic had sunk to a level whereby the sea was just washing over the surface of the forward end of 'C' deck. This seems to have been at 2pm..45 minutes later.
Plotting Mr. Wilding's water line for Dillons time of the water coming into boiler room 4, points to Titanic having submerged her bow by 26 feet by 1:15am.
Plotting Rowe's evidence, suggests she had sunk it by a total of 29 feet by 2am.This meant that her draft at the bow had only increased it by 3 feet during the previous 45 minutes.!
Obviously the angle of tilt by the bow had not increased significantly!

The small change in bow-down angle is to be expected.
Because of the position of boiler room 4 in the hull, Titanic would not trim much more by the head after 1-30am and increasingly, Titanic would be sinking bodily.
What is more, the wt doors from boiler room 4 right aft to the stern were wide open. At that time, the water in boiler room 4 would have started flowing aft as the depth in that boiler room increased. It is significant that at that time, there would be no appreciable moment causing the vessel to tip more by the head i.e. increase the angle therefore there could never have been a break angle much more than 6 degrees.

However, the small change in bodily sinkage between 1:15am and 2:am is puzzling. Could one or either of the witnesses have got the times wrong?
Up until 1:15, Titanic was sinking bodily at a rate of about 13.5 feet per hour. If this rate had continued, the forward well deck should have been awash by 1:45 at the latest! What slowed-down the rate of sinkage?

Perhaps it was Dillon who got it wrong? He said the last proper lifeboat was leaving when he arrived on the aft well deck some time between 1:15 am and 1:30am . However other sources state this did not happen until 20 minutes later, at 1:50am!
Dillon said the engine room clocks had been set back 20 minutes! Could this be the source of the problem?
20 minutes from 1:50am gives us a Dillon launch time of 1:30am.

What about the break-up itself?

As Mr Wilding said, a ship is considered as a girder. The main strength members are the topmost line (strake) of side shell plating at the main deck.. deck C .. the shear strake...and...the Keel and the plating on either side of it.
But these longitudinal strength members have their greatest strength in the vertical plane. I.e. up and down the way. Titanic was heeled over to port!
This would mean that there would be a bending moment caused by gravity acting downward on the partially upward -facing starboard side of the vesssel which was suspended in the air. In this way a sort of twist would be imposed on the section. The result would be an opening up of the aft expansion joint in the superstructure while the submerged starboard side of the ship at the round of bilge at wt bulkhead 'J' ... just ahead of the main engines bed plate ... where the height of the double bottom tanks is reduced... would be put in tension.
If that particular area failed catastrophically, the sides of the ship in that area would spring apart and the water would pour into both exposed internal parts of the hull. The hull would separate vertically, possibly on both sides of 'J'. Finally breaking away completely to form two separate parts. This would cause the stern portion to briefly right itself before the weight of the main engines in the forward part would cause it to tip over, before finally sinking while twisting away to the left and downward. The front portion, having lost the centre of flotation, would tilt rapidly, wounded end upward, then sheer left then right, and head bow downward into a spiral.


On the way down, any water tight or airtight enclosed spaces such as Double Bottom Tanks would be increasingly effected by the pressure. Initial stress damage would be agravated and become distorted.. even breaking free from secure mounting etc.
When the bow hit the sea-bed, it dug-into the mud and the flat bottom behind it crashed down onto the sea bed
All the top-hamper above the flat bottom tried to telescope but only succeeded in bellying-out the side plates and buckling any stanchions or fashion plates.
It possibly came to rest straddling a sub- mud ridge. Over the years, the hull sagged on each side of the ridge leaving it bent as we see it today!

You saw it here ladies and gentelmen. James Cameron; eat your heart out!


James.
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Re: Shallow Angle Break Theory

Postby Joshua Noble on Fri Apr 13, 2012 5:46 pm

Your assessment of the sinking based on accounts is great Jim, but one would think the ship would be able to take 6 degrees without breaking. Some survivors' accounts seem mostly to be in favor of a larger angle in the final plunge though.

Below is a link to the result of James Cameron's Final Word which was the combined effort of several historians (some of which are on this forum):

http://www.youtube.com/watch?v=FSGeskFzE0s
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Re: Shallow Angle Break Theory

Postby Jim Keller on Fri Apr 13, 2012 8:15 pm

Regarding eyewitness accounts, also remember that humans are lousy at estimating grades while on them. We see this in rock climbing all the time. A 45% grade is described as "vertical" by most people. A 5% grade on an improved trail is estimated to be around 15% by hikers. I'm inclined to assume that every estimate of the angle of the ship in the eyewitness accounts needs to be slashed in half at least unless it came from someone experienced with measuring grades.
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Re: Shallow Angle Break Theory

Postby George Behe on Sat Apr 14, 2012 7:05 am

Hi, Jim K.

>Regarding eyewitness accounts, also remember that humans are lousy at estimating grades while on them.

That's true. However, the best estimates of the angle that the ship reached before the breakup were made by people who were not on the ship at all but who were carefully observing the scene from the safety of their lifeboats. They estimated the pre-break angle to be about 30 degrees, and I accept that estimate without reservation.

It also pays to remember that not all calculations made by engineers are necessarily accurate (as the designers of the Tacoma bridge would willingly attest.) I recall seeing a humorous video of a man who was standing on a horizonatal tree branch in his back yard. Even though the gravitational force on the branch was exactly the same throughout the entire video, the man stood on it for at least fifteen seconds before it suddenly broke under his weight. In other words, the branch had to gradually weaken throughout that fifteen-second period before it finally broke, and I feel the same thing happened to the Titanic: i.e. it was gradually weakening as it rose out of the sea and passed through the point of greatest stress, and the structure finally failed completely when it reached the observed thirty-degree angle.

George
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Re: Shallow Angle Break Theory

Postby Jim Buchanan on Sat Apr 14, 2012 2:38 pm

Hello George!

"It also pays to remember that not all calculations made by engineers are necessarily accurate "

I agree with you entirely. However, you do not need to be on Titanic or any other ship. All you need is an accurate set of blue prints and the stability information for the particular ship in question. Wilder had access to these and did not need to refer to 'Olympic' at that stage.
He was feeding-back information to the Drawing Office at H&W Belfast as soon as it became available from the evidence. From it and the Belfast people, he developed a series of water lines which showed Titanic at various times during the period from when the bow became flooded until the hypothetical moment just before the water topped WT Bulkhead 'F" between Boiler rooms 4 and 5.

Given the evidence, he would have a picture of the ship steadily taking in water along 200 feet of her starboard side from the forepeak to just aft of the number 6 boiler room.
He would know the position of these compartments relative to the centre of flotation and be able to run a series of scenarios which would show him exactly how the hull would behave.
As I pointed-out, progressive flooding from bow toward stern means that more and more of the flood water is used up in sinking the ship bodily.

As for the down-by-the- head angle: Wilder would know that for the bottom of Titanic to have attained a 30 degree angle to the surface of the sea while tipping round her centre of flotation, the top of her foremast would need to have been just under water. That did not happen till after she sank!

He would also know that for the forward well deck to be awash so late in the proceedings, the aft end of the ship could never have been out of the water by 30 degrees at the same time. For that to happen, the ship's bottom would need to have been clear of the sea from just under the bridge all the way aft. That did not happen until the bow up-ended!

No George. I think we have to accept the evidence that was given by not a few to the effect that the lights went out row by row as the ship gardually settled deeper and deeper. That is not an indication of steep angle at all.

Hello Josh


Much as I respect James Cameron and what he has done as well as all those clever people at Wood's Hole etc, I take exception to one or two things he postulates.

I also know that Naval Architects do not entirely agree with all of what his theory portrays.

For a start of, I and others do not do not agree with his scenario of Titanic's efforts to avoid the iceberg. If we believe the evidence of the quartermaster on the wheel at the time, there simply was not enough time to perform turns as seen in the video clip.
It opens with Titanic's bow having already turned 2 points to port before impact. If the QM was honest then he only had as much time to change Titanic's course as it took for him to get the helm hard over. That's about 5 seconds!

He also misses a crucial point in the sinking. I mean the point where the flooding causes very little sinkage but a great deal of tipping by the head. This would be the time before the water got to the top of water tight bulkhead 'F'. Before this happened, it would have got to the top of bulkhead 'B' and then flowed forard into the compartments behind 'A'. This would have caused the bow to tip more and the stern to come out of the water. Thus, just before the water reached the top of 'F' there would be a tremendous stress in the area just in front of the main engine rooms.
Ships and the stuff in them are designed to be supported by water. In dry-dock, unequal bottom loading is borne by keel and bilge blocks. The bit suspended in air aft of bulkhead 'F' was the heaviest part of the ship. There can be no doubt that if this bit lost the support of the sea, it does not require rocket science to deduce that very soon something is going to give. If not then, then the next time that area comes under the same stress. Now that's crucial, since that's where the double bottom height is reduced and where the shortest wt compartment was located. Additionally, there was an almost unbroken vertical path for crack propogation in that area and that's where the hull failed and the forward part of the double bottoms popped out!

Cameron's film show us one thing and that is: that apart from just before the water got over the top of bulkhead 'F'; the only time anyone could have seen clear water under the hull at the stern was at the very end.

However there is a puzzle there too. Perhaps someone can explain it?

All the wt doors were open right to the stern. As the ship settled bodily, water would flow aft The engine rooms and every compartment aft of them were flooded 30 minutes before the ship sank. We must conclude that this flooding continued until the very last moment so, if the aft end, the heaviest end, was getting heavier by the minute, what made Titanic tip by the bow?

Interesting stuff!

Happy Titanic day!

James.
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Re: Shallow Angle Break Theory

Postby George Behe on Sat Apr 14, 2012 6:30 pm

Hi, Jim B.

I disagree with your dubious interpretation of the evidence, but I'm perfectly content to let "Report Into the Loss of the SS Titanic: A Centennial Reappraisal" express my own viewpoint (which you are free to disagree with if you wish to.)

All my best,

George
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Re: Shallow Angle Break Theory

Postby Jim Buchanan on Sun Apr 15, 2012 10:46 am

Good morning George!

Nice 'punt' for the book! Unfortunately, ... much as I would like to.... my pension doesn't allow me to indulge.

However, I'm sure you can set the records straight without revealing anything to a potential reader.
All I ask is that you explain one simple technical point which applies to all ships... not just Titanic.

Please explain how a ship that is flooding progressively toward the stern can elevate her stern 30 degrees above the sea surface yet keep her bow above it at the same time?

You are allowed to consult!

While you're at it, you might like to have a re-think about the following:

Lightoller's evidence suggests that the water was level between the top of the bridge housing and the Crow's Nest shortly before Titanic took her final plunge. The Crow's nest was about 10 feet above the point where he was standing and some 90 feet away. therefore Titanic must have been down by the head by 8 degrees at that time.
Wilder's evidence suggests that Titanic was down by the head by 5 or 6 degrees at least 50 minutes earlier so there could not have been much change during that time as far as tilt by the head was concerned.
However, she had sank bodily by 36 feet since QM Rowe saw the forward well-deck awash 20 minutes earlier and 23 feet since she hit the iceberg....a total of about 59 feet.

We 've just celebrated 'Titanic'. Soon it'll be the turn of the Olympics. Like past champions, we should never rest on our laurals but keep questioning.
Given it's distinguished authorship, I'm absolutely sure the book is a wonderfull bit of work and very much worth every penny. But I'm equally sure it is not the final word on the matter.

Best wishes,

James.
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Re: Shallow Angle Break Theory

Postby George Behe on Sun Apr 15, 2012 12:20 pm

Hi, Jim.

>Nice 'punt' for the book!

It wasn't really a punt for the book - it was just my way of saying that my views are already out there for anyone who might be interested in pursuing the matter.

Hope you'll have a good Sunday.

All my best,

George
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Re: Shallow Angle Break Theory

Postby Jim Buchanan on Sun Apr 15, 2012 4:30 pm

Thanks George!


I just can't leave the thing alone as it stands. Too many un-answered questions!


Same Sunday to you!

All the best,

James.
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Re: Shallow Angle Break Theory

Postby Joshua Noble on Sun May 20, 2012 4:35 pm

Another argument favor of the shallow angle that I thought of today was the story of Frank Prentice, the last of the crewmembers. He said he was holding onto the triple screw warning sign on the stern and then jumped off narrowly missing the propellors. The fact he survived the drop he said was about 60 feet (it was more but he said that in his later years) into the sea after NMGTT was played and survived proves in my opinion it was shallow.
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Re: Shallow Angle Break Theory

Postby George Behe on Sun May 20, 2012 5:19 pm

Salaam.

In his MacLean's interview, Prentice twice mentioned the fact that the stern was "almost vertical" when he jumped from the ship, and in his Soton Echo interview he said he was actually laying on top of the triple screw warning sign before he jumped overboard. IMO that's pretty conclusive evidence that the stern went vertical after the break. (In 1912 Prentice said he jumped about 75 feet into the water, so the stern was close to being completely submerged by the time he left the ship.)

As for the pre-break angle, the two survivors who gave specific estimates of that angle both said it was around thirty degrees, and I see no particular reason to disbelieve those two independent estimates.

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Re: Shallow Angle Break Theory

Postby Jim Buchanan on Sat Jun 02, 2012 1:45 pm

Actually it is fairly easy, given the tonnage and location of floodwater in the compartments forward of Boiler room 4 to calculate the amount by which the bow went down and therefore the angle. There would have been an intial, maximum down ward by the bow tilt and thereafter, as the flooding progressed toward the stern, there would be more bodily sinkage that head tilting. I'll let you know what I think it was when I get a moment.

James Buchanan...
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Re: Shallow Angle Break Theory

Postby Ronnie Cassinello on Tue Jul 03, 2012 5:10 pm

Jim,

Have you taken into account that the centre of floatation would tend to move aft as the displacement created by forward compartments tends towards zero?

In an 'ideal' compartmentalised sinking with a rigid hull, as flooding moves from forward compartments to the aft, the longitudinal trim angle will increase right until the hull is no longer displacing its own weight (i.e., it sinks).

This is because flooded forward compartments provide a turning moment in the longitudinal direction. An opposing moment is set up by the aft lifting out of the water. However, as each forward compartment in turn becomes flooded it becomes an extra dead weight, providing an increasing moment - and as less of the stern is now available to provide a counter-moment, the trim angle increases.

In an extreme scenario you would end up with only the aft-most compartment bouyant, with the whole of the rest of the ship beneath - at this point it is perpendicular.

In the real world, obvously, this almost never happens - usually the hull as a whole would achieve negative bouyancy long before this, or the effects of lateral trim take over (capsize), or the ship itself breaks apart - although it does seem in the case of the Titanic that this did happen to the stern section (helped along by the weight of the engines, no doubt).

Ronnie
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Re: Shallow Angle Break Theory

Postby Jim Buchanan on Mon Jul 23, 2012 12:03 pm

Hello Ronnie (if you're still there!)

Yes, I understand the mechanics of a sinking ship.

You must remember that the Titanic sinking sequence was in three parts: Steady loss of buoyancy followed by increase in draft due to added weight, followed by sudden and catastrophic loss of buoyancy. Because of this, the pivotal 'centers' were dynamic. Unless we know the exact sequence of events during the sinking process, the best we can do.. even with the aid of a computer... is to come up with an educated.. 'all things being equal' guess.

James.
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