Titanic's Hull

S

Stephen Stanger

Guest
I think that the positioning of the boiler rooms (horizontially across the beam instead of up the length) left the flanks rather vulnerable to any penetration. Didn't Andrews recommend a double hull for the Titanic but Ismay declined?
 
Dec 4, 2000
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Stephen -- Double hulls (one inside the other) do not automatically mean more safety. The outer shell on Britannic is thought to have been a major factor in its capsize.

Loss of stability results when the outer double hull is breached on one side of a ship, but the inner hull remains intact. Loss of buoyancy on the damaged side causes an immediate list which can be more threatening than the original damage. This seems to have happened to Britannic.

The single skin of Titanic meant that any damage would flood a full compartment, but that this flooding would be transverse (across the beam of the ship.) Transverse flooding does not automatically create a loss of stability. Titanic remained relatively upright despite heavy damage because stability was maintained despite the downward tipping of the bow.

In reality, however, the bow of another ship can easily penetrated both the inner and outer hulls. Stockholm's icebreaker bow went nearly halfway through Andrea Doria. This much penetration would have rendered a double hull useless.

-- David G. Brown
 
Jan 5, 2001
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David G. Brown,

I often hear people say that Britannic's double hull might have contributed to her eventual capsize, but I don't quite understand how. Can you enlighten me?

Best regards,

Mark.
 
Dec 4, 2000
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Mark -- An empty void up the side of a ship is really just an unfilled ballast tank. If the outer plate is pierced, water fills this tank. The result is, in effect, asymetric ballasting and the ship takes an immediate list. Disaster can result when this list is combined by the loss of stability from other flooding.

Modern ships often have what appear to be double hulls, but with a difference. The space thus created is filled with either bunker fuel oil or ballast water. Should the outer hull be pierced, the ship does not experience nearly as much loss of stability. Obviously, a piercing a water-filled tank does not change the transverse balance of the ship because the weight of the ballast water lost equals the weight of the flooding water gained. Net change zero. There is some change in weight if lighter oil leaks out and is replaced by heavier water, but this is minor compared to the flooding of an air-filled tank.

-- David G. Brown
 
Jan 5, 2001
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I think I understand this fully now, but I am not aware of any evidence about Britannic's double hull being flooded?
 
Dec 4, 2000
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Mark -- everything I know about Britannic is hearsay as I have done no serious research on that vessel. However, the heavy list taken by the ship does indicate a catastrophic loss of stability.

-- David G. Brown
 
Jan 5, 2001
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David,

Thanks for your reply. I've posted my reasoning about the double hull's state in the earlier Britannic thread 'Report of a formal investigation...' so this thread doesn't wander from its topic.

Best regards,

Mark.
 
May 9, 2001
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David,
Wouldn't the pressure of a puncture in a double bottom filled with some fluid cause a hydraulic effect within the chamber and thus exert a strong force against the rest of the chamber? (I don't know if that made sense the way I've written it.)
I mean if a double bottom had an empty chamber in the middle, any force from a collision would be limited to the outer shell. But if you fill the middle with a fluid, then the energy from the collision can be transfered to the inner shell through the fluid. Wouldn't that mean that the fluid filled chamber between inner and outer shells would be more of a danger than the instability caused by uneven flooding of a relativley small area?

Yuri
 
Dec 4, 2000
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Yuri -- damdifino. Seriously, I am not a naval architect or any sort of an engineer. My opinions about the structural integrity of dry versus wet tanks can only be a guess.

I would think that a full tank would be less likely to puncture because of the hydraulic effect you mention. Just a guess.

Transverse stability is very serious business on ships because they are so long compared to their widths. A slight miscalculation in transverse weight can roll a ship over, while the same amount of weight may not cause more than a slight tipping of the bow or stern. I have done real-life inclination tests with commercial passenger vessels. They are risky in the extreme because the object is to find out if the ship will roll over should all of the passengers crowd the rail on one side. (That, of course, is what is believed to have capsized the Eastland while still tied up in the Chicago river with the loss of more than 835 people.)

I have heard of a case in which one small passenger vessel was forced to remove a longitudinal bulkhead because it represented a capsize threat. This bulkhead divided one regular compartment into two longitudinal (running lengthwise along the keel) ones. Should the compartment on one side of that bulkhead have flooded, the vessel could have been rolled over by the movement of its passengers on the decks above.

On the other hand, the flooding of a single transverse compartment of conventional design should -- in theory -- have little effect on the ship's transverse stability. This is because the water would quickly level itself port-to-starboard inside the compartment. The ship would lose buoyancy, not stability.

-- David G. Brown
 
May 9, 2001
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I remember a picture of a famous liner that caught fire while docked in New York and eventually rolled over onto her port side.
I always wondered, why did she roll over? I mean if she was gutted by fire, that may ruin her interiors and damage the integrity of her upper decks, but why did she roll? Then I figured it out. The firemen sprayed so much water into her to try to put out the fire that she became unstable and eventually rolled over, causing even more damage. This was in the 30's or 40's I believe.

Titanic was never reported to have experienced any more than a slight list shortly after the collision. I assume that is because she had no longitudinal bulkheads seperating her compartments into port or starboard sides. Was this slight list caused by the water in the forward cargo holds pooling up on the starboard side of the fireman's passageway?

Yuri
 
Dec 2, 2000
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Easley South Carolina
Hi Yuri, I think the ship you're referring to is the Normandie which burned on 09 February 1942. The cause of the fire itself isn't difficult to understand. An idiot was using a blowtorch to do some hotwork and the sparks that went flying landed among burlap wrapped bundles of kapok life preservers. As to the rest, you pretty much nailed it on the head.

On the Titanic's list, I think it corrected itself fairly quickly for the reasons you already mentioned. There were longitudinal bulkheads, but none of them watertight, so it wasn't much of a trick for water to flow from one side to another through assorted doors, breezways, natural circulation openings and the like in each of the different rooms.

Cordially,
Michael H. Standart
 
Dec 4, 2000
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Yuri & Mark -- Please save questions regarding any lists or lolls of Titanic for Captain Erik when he returns. His thoughts on this subject are at least interesting and perhaps revolutionary. I want him to reveal his ideas in his own words, however, so I am remaining cryptic at the moment. So, welcome Erik back with these questions.

-- David G. Brown
 
Dec 4, 2000
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I can give you a lot more than a hint, but out of deference to Capt. Erik, I won't. The concept is entirely his. I do not want to steal anything from him.

If you read between the lines, however...

-- David G. Brown
 
May 9, 2001
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David,
Can you, or someone, give me a better description of the firemen's tunnel that ran along the tank top in the forward sections?
Specifically, its length, width, height, and maybe an idea of how it was lighted, or what it would have looked like from the inside, and the outside. Just anything you can provide as far as a complete description of this tunnel.

Thanks,
Yuri
 
Dec 2, 2000
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Yuri, my understanding of the Fireman's Tunnel was that it was basically a watertight tube with two watertight doors in a vestibule on the after end leading into Boiler Room Six, and a spiral stairtower on the forward end which led up to the crews quarters as high as D deck through a stepped section of Bulkhead B. I'm not sure how it was lighted, but I doubt that it was anything more fancy then bulbs enclosed in one of those small protective cages. (I could be dead wrong on that one too.)

The idea was to make it possible for the firemen to get to the engineering plant without having to go through any of the passanger accomadations. As far as I know, this was a feature peculier to the three Olympic Class liners and was never repeated in any other design.

Cordially,
Michael H. Standart
 
May 9, 2001
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If I were standing in the bottom of hold number 2, could I possibly have climbed on top of the tunnel? Or did it actually form a wall that seperated the lower deck of the cargo holds into two compartments, port and starboard?

YS