"Spilling Over" the tops of the bulkheads

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Re: "Spilling Over" the tops of the bulkheads

Postby ardtornish » Mon Jul 22, 2013 9:19 pm

Hello Aaron,

I would not be surprised if that many people were up there but I recall that someone saw a lot of people in the aft well deck who were tumbled over in a bundle as the ship lurched to port.

It would surprise you how few people would be needed to cause or cure a list.

When a ship is new, they perfor what is known as an 'inclining Experiment". This involves moving a known weight side-ways across the ship for a known distance and measuring the deflection of a pendulum on a very long line.
Don't know what weight they would have used for Titanic but I do know that in much smaller ships of a 10th the weight of Titanic, they moved a mere 15 tons across 35 feet and produced a list of about 1.5 degrees.
It depends on how high up the weight is as well as another factor or two. But I would guess that the weight transfer across Titanic's boat deck was in the region of 75 tons. However it was transferred across a much greater distance.

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Re: "Spilling Over" the tops of the bulkheads

Postby Aaron2010 » Mon Jul 22, 2013 10:11 pm

Here is a small ship rolling over. I wonder, do you think if there were a hundred people on the starboard side, would the ship still roll over? Would the weight of people on the starboard side keep her balanced?



http://www.youtube.com/watch?v=IPoAOXf8RIo



I wonder if this happened to Titanic's stern. Survivor Charles Joughin said:


"It was like as if the iron was parting......I kept out of the crush as much as I possibly could, and I followed down, getting towards the well of the deck, and just as I got down towards the well she gave a great list over to port and threw everybody in a bunch except myself. I did not see anybody else besides myself out of the bunch.....I was on the side, practically on the side then. She threw them over. I clambered on the side when she chucked them."

Q - How many people there were in this crush?
A - I have no idea, Sir; I know they were piled up.

Q - What do you mean when you say, “No idea.” Were there hundreds?
A - Yes, there were more than that - many hundreds, I should say.

Q - You said this vessel took a lurch to port and threw them in a heap. Did she come back? Did she right herself at all?
A - No, Sir.

Q - She took a lurch and she did not return?
A - She did not return.....I eventually got on to the starboard side of the poop, on the side of the ship.....I did not see anybody else.




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Re: "Spilling Over" the tops of the bulkheads

Postby ardtornish » Tue Jul 23, 2013 12:42 pm

Hello Aaron.

What an emarrassment for the builders!

Obviously there was something wrong with the pre-launch calculations. However,I don't think any number of people on the deck of that one would have made much of a difference :)

As for Joughin's description: looks like he was describing the last seconds in the life of the stern section. I can well imagine the following:
Ship down by the head and slightly to port. Portside shell -plating fractures vertically at forward end of the main engine room. A huge, overwhelming volume of sea-water instantly engulfs the port side, causing it to heel over to the left and instantly removing any remaining buoyancy from the forward part of the hull. At the same time, the unsupported weight of the aft end section which had been atempting to to bend back and downward toward the sea-surface, is aided by the hull weakness and the aft section of the hull starts to return level. As it does so, water enters the aft end of the engine room, accellerating the bending moment. ( Trimmer Dillon describes this in his evidence when he said the aft funnel seemed to tip back toward him).
Thus, an anti-clockwise and downward-hinging twist is imposed in the remaining intact hull plating between stern and forward submerged parts. This attempts to make the stern part follow it. Fortunately(for Dillon, Joughin and others), at that moment, the verical fracture in the ship's side has weakened the ship girder and it simply propogates right round the hull and the hull breaks in two parts with a tearing, wrenching sound. The stern section briefly returns to the upright before following the forward part to the bottom. Just a guess! :idea:

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Re: "Spilling Over" the tops of the bulkheads

Postby Dave Gittins » Wed Jul 24, 2013 10:11 am

Concerning correcting a list, Edward Wilding calculated that moving 800 people through 50 feet would cause a list of 2°.

Whether anybody heard Lightoller calling them to move and whether anybody did so are another story.

I'm sure I read somewhere that a stability test was done on Titanic in Southampton, using a big weight, but I don't think any figures survive.
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Re: "Spilling Over" the tops of the bulkheads

Postby ardtornish » Wed Jul 24, 2013 12:46 pm

Hello Dave.

They performed that experiment on every new ship. It was the way to establish the height of the Metacenter above the Center of Buoyancy when the ship was at her lightest draft (displacement).
From this and other information, the builders developed the Deadweight Scale and Curves of Stability. A copy of these were supplied to the ship. From them, the ship's officers could then determine the ship's condition at any moment in time. Titanic would have been no different.
I was surprised to learn that the experiment had been made at Southampton since it requires very strict adherence to particular conditions. As well as weather these concern boilers, tanks, moveable objects and people. However, here's the proof that it was:
"Senator SMITH.
What was done when you reached Southampton?
Mr. LIGHTOLLER.
The ship was heeled for stability.
Senator SMITH.
Just describe that.
Mr. LIGHTOLLER.
The builders knowing the exact weights on board, additional weights are placed on each side of the ship. A pendulum is suspended in the most convenient place in the ship with a plumb on the end of it, and a method of registering the difference with the plumb line; a number of men then transfer the weights from one side of the ship to the other, bringing all the weight on one side and transferring the whole of it back again; and with this, I believe the builders are able to draw up a stability scale."


The original work done to establish stability information would have been retained by Harland & Wolff. White Star whould have had a copy at the Southampton Office. The information was unique to Titanic. The Olympic data might have been used but I doubt it since an experiment was made specifically for Titanic.

Ard.

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Re: "Spilling Over" the tops of the bulkheads

Postby samhalpern » Wed Jul 24, 2013 5:42 pm

The metacentric height for Titanic was estimated by Chris Hackett and John G. Bedford at GM = 2 ft 7.5 in (2.625 ft.) based on 1911 data taken from Olympic. The draft of Titanic after completing about 2/3 of her voyage on the night of April 14, 1912, was estimated (by naval architect Edward Wilding and presented to the Wreck Commission) at T = 32 ft. 3 in. (32.25 ft). At that draft, Titanic’s displacement was estimated at W= 48,300 long-tons (see below). The initial righting moment for Titanic on the night of April 14, 1912 as afunction of angle A would be approximately 2,200 A foot-tons for small angles of A given in degrees.

[From the entries for Titanic in the original record book “Particulars of Completed Ships” in Harland & Wolff archives, the change in displacement in tons per inch immersion (TPI) was listed at 143.8. The displacement at her load draft of 34 ft. 7 in. was 52,310 tons. Wilding derived a mean draft at the time of collision at 32 ft. 3 in. That is a difference of 28 inches between the vessels load draft and her draft on April 14. The change in the vessel’s displacement is therefore 28x143.8 = 4,026 tons. Subtracting this number from the load displacement gives 52,310 - 4,026 = 48,284 tons for the night of Apr 14. Wilding rounded this to 48,300 for his working estimate.]
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Re: "Spilling Over" the tops of the bulkheads

Postby Aaron2010 » Wed Jul 24, 2013 6:59 pm

It is amazing how the movement of several hundred people could alter the position of the ship. Was this a problem in those days? I wonder how the troop transports managed to stay upright. They carried tens of thousands of people. The Leviathan carried more than 14,000 during one voyage.




The deck of the Queen Mary


qmtroops.JPG

qmtroops2.jpg
qmtroops2.jpg (119.95 KiB) Viewed 8074 times



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Re: "Spilling Over" the tops of the bulkheads

Postby ardtornish » Thu Jul 25, 2013 4:45 pm

Hello Aaron.

As usual..great pictures!

Very many ships carried troops in WW1, WW2, the Korean War, etc. It was all to do with the stability condition of the ship before the troops embarked. They made sure that even if the troops had to muster on deck.. say in an abandon ship situation.. she would not capsize by reason of too much top-weight. To do this, they made sure that the ship was very stable before embarkation day and would remain so during the voyage; even if she were holed to a certain extent.

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Re: "Spilling Over" the tops of the bulkheads

Postby Carpathia » Sat Oct 26, 2013 2:58 am

A week or so ago, my mom brought up a point which I didn't quite have an answer for.

Let's say the iceberg only opened four compartments up to the ocean and Murdoch closes the watertight doors.

With the way the ship was built, what would have stopped the water from spilling over the top of the bulkheads? I know the Olympic's collision with the Hawke opened up two compartments and she limped back to port.
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Re: "Spilling Over" the tops of the bulkheads

Postby Dave Gittins » Sat Oct 26, 2013 10:18 am

Modern calculations show that with the four foremost compartments flooded and the water-tight doors closed the ship would have remained afloat, as the water would not have reached the top of the bulkheads.

Whether she could have been salvaged from that position, using the technology of 1912, is another story.
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Re: "Spilling Over" the tops of the bulkheads

Postby Atlantic1912 » Thu Oct 31, 2013 6:41 am

Dave Gittins wrote:Modern calculations show that with the four foremost compartments flooded and the water-tight doors closed the ship would have remained afloat, as the water would not have reached the top of the bulkheads.

Whether she could have been salvaged from that position, using the technology of 1912, is another story.


Hello,

Does that take into account pumps or purely on the buoyancy of the ship?
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Re: "Spilling Over" the tops of the bulkheads

Postby Dave Gittins » Thu Oct 31, 2013 8:59 am

Purely the buoyancy.
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Re: "Spilling Over" the tops of the bulkheads

Postby Carpathia » Sat Jan 06, 2018 6:10 am

I've been wondering this off and on for a little while.

I know Titanic was designed to stay afloat with any two compartments flooded or the first four. What I'm wondering is if 3 compartments midships or aft were flooded, why the ship would sink under those conditions compared to the bow?
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Re: "Spilling Over" the tops of the bulkheads

Postby Mark Chirnside » Tue Jan 09, 2018 9:40 pm

Carpathia wrote:I know Titanic was designed to stay afloat with any two compartments flooded or the first four. What I'm wondering is if 3 compartments midships or aft were flooded, why the ship would sink under those conditions compared to the bow?


It's more complicated than that, Carpathia. The ship would not necessarily sink under the scenarios you described.

See Sam Halpern's webpage: http://www.titanicology.com/FloodingByCompartment.html

Best wishes

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