Water Pressure Against the Hull

[Aaron_2016]

When the Titanic settled low in the water and her port side plates settled down more than 100 feet below the surface, would the water pressure at that depth push against the hull and burst open her plates? When I try to push a water basin down into a bath full of water the water basin will resist and the pressure fights back and pushes upwards. Does anyone know what kind of resistance there was within the compartments that were destroyed when she broke apart as they possibly resisted and were being pulled down against their will? When a plastic bottle is pulled down just 30 feet it is squashed flat by the pressure. What would happen to the Titanic's hull (primarily in the region where she broke) when it sank down more than 100 feet in that icy region of the Atlantic? Did the pressure squeeze against her hull plates and breach the port side compartments where she broke apart?

At what depth would the hull buckle open by the pressure? A number of survivors said they were blown into the air and thrown into the sea by a terrific explosion. Did the something inside react to the pressures and burst out and break the ship apart?

It appears a large section of hull plating has been torn completely off. Is it possible that when the ship settled low in the water there was a reaction to the water pressures at that depth which stripped off the hull like paper?

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[Samuel Halpern]

Having fun in the bath tub, Aaron? Congratulations on your rediscovery of Archimedes principle. At 100 ft, the pressure of sea water is 44 psi. At her normal depth of 34.5 ft, the pressure against the hull is just over 15 psi.

 

[Steven Christian]

Correct. As every scuba diver knows at least when I got certified 33 feet equals 14.7psi. Equal to one atmosphere at sea level. I'm not sure what her crush depth would be as she wasn't designed for that. But due to different compartments construction I would think it would vary.

 

[Aaron_2016]

Having fun in the bath tub, Aaron? Congratulations on your rediscovery of Archimedes principle. At 100 ft, the pressure of sea water is 44 psi. At her normal depth of 34.5 ft, the pressure against the hull is just over 15 psi.

Thanks. Had to fill the bathtub because the council are working on the water pipes and road outside. Thought it was a good opportunity to test a few theories.

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[Rob Lawes]

With the exception that with her hull full of water there would be no / very little pressure difference between outside and inside. As we know from hydraulics, you can't compress a fluid, therefore there would have been no crush effect on her hull.

 

[Aaron_2016]

Thanks, although I was thinking of the dry compartments where she broke apart. Also boiler rooms 4 and aft. This region would be mostly dry at the bottom and the hull might have been bulging in and bursting open due to the pressures outside squeezing in.

 

[Samuel Halpern]

What broke the back of Titanic was excessive stresses on the shear strake. She was designed to withstand 10 tons psi of stress with 1-inch mild steel. The stress due to bending moment exceeded that design point.

 

[Aaron_2016]

[y understanding is that the excessive stresses put on the hull were just one possible theory for the break up, but not the absolute cause of the break up. For instance a number of survivors described how they were blown into the air or witnessed others blown off the deck by a terrific explosion, as well as coal, steam, smoke, and sparks seen shooting out of the second funnel. Is it possible that the water pressure had breached open the port side and caused a catastrophic event under funnel 2 to burst out and break the ship apart in the process as a number of survivors saw the 2nd funnel fall first and at the same time she broke.

 

[coal eater]

well first funnel was taking smoke from boiler room 6 and 5....funnel 2 was doing it from boiler 4 and 3. at the time of sinking only boiler room 2 and 3 were giving steam so funnel nr 2 was used aswell....on wreck we can see boilers from boiler room 2,they are imploded little but not destroyed. we dont know fate of boiler room 3 (how much damage they got) after water flooded it..we dont know if WTD was closed between br2 and 3 and if escape ladders to br 3 were closed aswell.. inquiries dont have anything related to boiler rooms before/during/after ship break up .

there was not much steam pressure to force coal and sparks throught funnels,there was minimal pressure to run just dynamos for lights as at this time probably any pumping water out actions ceased before break ..when water flooded boiler room 4 eoungh to render it useless probably from this stage there was no sense to keep pumping water because it was total defeat

 

[Mark Chirnside]

...the excessive stresses put on the hull were just one possible theory for the break up...

Aaron, if the stresses the hull was subjected to did not exceed what it was able to withstand then it would not have failed.

Best wishes

Mark.

 

[Aaron_2016]

True, but there could have been any number of possible scenarios that contributed to the failure and breaking of the ship on the surface. e.g. If her hull was breached by the water pressure then it might have led to a rapid failure of her structure which helped her break apart. Sounds characterised as explosions, wrenchings, tearings, bulkheads collapsing, and watertight doors failing were all heard before she broke apart. Some estimated the first explosive sounds occurred between 10 - 20 minutes before the second larger explosive sound. Smoke, sparks, coal and steam were seen rocketing into the air immediately after the explosive sound. I can't help but wonder if there was a serious breach that initiated the break up process to begin.

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[Samuel Halpern]

The stresses on the hull girder due to excessive bending moments reached a point where structural failures started to take place. Sounds characterised as explosions, wrenchings, tearings, bulkheads collapsing, are all consistent with stress failures. Whatever part water pressure played in the breakup was secondary at best. The hull could easily withstand an outside pressure differential that was several times greater than being subject to trochoidal waves of 42½ feet crest-to-trough.

 

[Samuel Halpern]

By the way, a breach in the hull that would allow water to find its way into the vessel would tend to equalize internal pressure with external pressure. It's why the rate of flooding slows as water rises within the ship.

 

[coal eater]

did double bottom was pushed inside hull during ship break up? we all know double bottom area between engine room and boiler room 1 was constructed with some flaw...
anyway did the upper decks break first or double bottom failure was first sign of breakup? where did it really start

just was wondering if stern started to go underwater did shell plating started to break away from structure?

 

[Aaron_2016]

The stresses on the hull girder due to excessive bending moments reached a point where structural failures started to take place. Sounds characterised as explosions, wrenchings, tearings, bulkheads collapsing, are all consistent with stress failures. Whatever part water pressure played in the breakup was secondary at best. The hull could easily withstand an outside pressure differential that was several times greater than being subject to trochoidal waves of 42½ feet crest-to-trough.

Problem about the bending theory is that her sister Britannic had her stern suspended for a considerable time and did not bend or break. I find it difficult to believe that it occurred to the Titanic and not to the Britannic or any other liner of considerable size. From what I understand there was a colossal explosive event which blew the second funnel off its foundation with streams of sparks, coal, smoke, and steam bursting out. Only now did the screams commence and the liner rocked and reeled violently, plunging, settling, buckling, and finally breaking.

Would be interested to see if the grating above the second funnel is resting with the remains of the funnel on the sea floor, or if it was blown off and landed separately by the explosive release bursting out.

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