The Titanic and her watertight compartments

[Brian Robert Rose]

Hello all,
As many of you well know, it has been commonly stated that the Titanic, thanks to her watertight compartments, could float with any two compartments breached, any three of the first five, or the first four. I have always wondered about the last one, the four compartment survival. Has anyone simulated this scenario, to see if the Titanic could actually float with the first four breeched? Of course, I am ignorant in the ways of shipbuilding and engineering, but it has always seemed to me rather amazing that the Titanic could float with her first four breeched? What if there were complications? I would love to hear your responses.

 

[Michael H. Standart]

>>Has anyone simulated this scenario, to see if the Titanic could actually float with the first four breeched?<<

With up to four, under very specific circumstances...an Olympic class liner could remain afloat with up to four compartments/sections breeched. This would have been calculated using a number of known values such as the hight of the watertight bulkheads, the volumn of the sections, and the weight of water that it would take to fill them as well as known values as to how far the mass would bring the hull down in the water. I don't know if it was ever simulated and I doubt it was needed. The people of this era were crackerjack mathmaticians, at least as good as any today and perhaps better.

>>What if there were complications?<<

Mmmmmmm...ask the Titanic and Britannic. They had 'complications' and sank as a result.

 

[Brian Robert Rose]

Excellent answer. I might clarify a bit. What I meant by complications was did the survival of an olympic class liner, in the event of a first four breech, depend on ideal conditions with no x-variable, i.e. open portholes, calm water.

 

[Michael H. Standart]

The survival of any ship in the event of a hull breech is always dependant on a number of conditions and variables. I don't think in this case that the ship would have needed "ideal"conditions. However it would be helpful if all of the portholes were closed (They weren't on the Britannic) and that all of the watertight doors worked well and were not rendered unusable by the primary damage itself. (There's evidence that this happened with at least one of the manually closed doors on the Titanic)

The fact that an Olympic class ship could float with up to four of the watertight sections flooded tells me among other things that these vessels had a lot of reserve bouyancy but that can only go so far. Some of my chums and I have been discussing the extra variable of the consequenses of structural damage which, curiously enough, seems not to have been factored into some of the forensics studies.

They should have been as such questions have a direct bearing on why the Titanic behaved as she did ( ipso facto broke up ) as she sank.

 

[Samuel Halpern]

Titanic was rated as a two compartment ship, meaning any two compartments could be flooded and she would stay afloat. However, that did not mean that only two compartments could be flooded. Looking at the floodable length curves for the Titanic there are lots of conditions where she could stay afloat if 3 or even 4 compartments were flooded. Of course this assumes no other structural damage which could cause additional failures. As an example of a few scenarios, the attached diagram shows five different flooding situations whereby the ship would remain afloat.

Cheers,

 

[Kelly Anderson]

The ship could float with the first four compartments flooded, and the collision opened five (so close!). The bilge pumps were in the engine room, with two ten inch (IIRC) mains running fore and aft. These mains tapered down as they passed though various compartments until the bow compartment was served by two three inch (IIRC) pipes, i.e. just enough to take care of minor leaks and condensation.

Now for the real Monday morning quarterbacking, so easily done at home with unlimited time to consider alternatives. One would suppose that they started pumping all of the flooded compartments right away. This is obviously pointless, since two ten inch mains won't keep up with 12 square feet of opening. I have often wondered if they had abandoned the first four compartments to the sea, and concentrated all of their pumping capacity on trying to keep the fifth compartment dry, if they would have been able to keep ahead of the leakage in just that compartment. The bilge suction mains would have increased to six or eight inch (IIRC) pipe by then, and they would have been dealing with just the tapering end of the hull damage.

Conrad Milster had another excellent point. Upon stopping, the fire room crews pulled the fires in the majority of the boilers except for a few which were used to maintain pumping and electrical power. That left perhaps 24 boilers without fires. Each of those huge scotch boilers held tens of thousands of gallons of water. If they had opened the blowdown valves on all those boilers as soon as the fires were pulled, it would have lightened the ship by hundreds of tons within a matter of minutes. Would the loss of that weight been enough to keep the fifth watertight bulkhead above sea level?

 

[Erik Wood]

Just a couple of things to add here.

1. Titanic was designed to survive flooding in four compartments open to the sea. That is it, this does not include the structural damage caused by the water intake, nor the structural which actually caused the water intake. There is a significant difference here and it should be noted. Recall that each additional pound of water is increasing the strain (for lack of a better word) on the structure and eventually something will give.

As I have said before there is no such thing as a completely watertight compartment. Eventually it will fail. The question is how long.

This means that depending on the type of structural damage no amount of pumping of water will save the ship. This has been discussed several times over. It was the lead topic of discussion at the Topeka Event some 4 years ago. It was also highlighted in Toledo and at the Maine Event.

2. Removing the weight from a stranded vessel is really only something done when the ship has grounded and you are using this technique to lighten the ship enough to remove it from whatever it has grounded upon. Weight and the calculation of stability and it's effect on the hull itself is something that was fairly new in 1912. It had been done in regards to cargo ships for years. But when it came to a damaged ship this type of shift was not only a rarely taught topic but not very well understood.

In this modern age we have the technology to assess these type things. Titanic did not.

I highly doubt the water from the boilers would have been sufficent weight wise to account for much. There is also some testimony and evidence which indicates the boilers in #5 where dry upon Barretts return.

In my view, the fifth compartment is a moot point. The structural damage caused by contact with the ice is what sealed the fate of Titanic. Not that fifth compartment.

 

[Michael H. Standart]

>>One would suppose that they started pumping all of the flooded compartments right away.<<

As far as I know, they did.

>> This is obviously pointless,<<

I'm not so sure the people in the last boats which were successfully launched would agree with that. Even if it's only a few minutes, any amount of time bought is better then no time at all. In this case, I suspect that the difference made was in getting two more boats away. On Collapsible C, this amounts to 40 people. On D, it amounts to 23.

>>Each of those huge scotch boilers held tens of thousands of gallons of water. If they had opened the blowdown valves on all those boilers as soon as the fires were pulled, it would have lightened the ship by hundreds of tons within a matter of minutes. Would the loss of that weight been enough to keep the fifth watertight bulkhead above sea level?<<

I don't think so. In fact, the safeties did open to dump excess steam and it took a bit more then a few minutes for this process to complete itself. The problem here is that the ingress of water was so rapid at first that it just didn't make any crucial difference.

And then there's the matter of structural damage that Captain Erik spoke to and this is nothing to take lightly. I can think of one contemporary example by way of the USS Samuel B. Roberts which struck a mine in the Persian Gulf. The crew had to brace up a bulkhead with a substantial amount of shoring to keep it from giving up the ghost. Even then, the ship was so much trouble that the Commander 5th Fleet Admiral Anthony Less had given authorization for the ship to be abandoned. I knew this man (He was one of my C.O.'s) and he would never have given any such authority lightly.

The crew didn't really didn't want to do this. With more mines as well as poisonous jelly fish, sea snakes and sharks to look forward to, small wonder! Through some really creative D.C. work, managed to save the ship. One of the tricks they used was to weld hard points to the ship's superstructure so they could literally hold it together...i.e. prevent her splitting in two...by running inch thich wire cable to hold her together. If they hadn't done this, it's just about a sure thing that the ship would have broken up.

It's rarely the primary damage which does you dirty. It's all the secondary stuff which follows which can ruin your day.

 

[Samuel Halpern]

Kelly. An interesting question on how best to keep the ship afloat as long as possible. What we don't know is what strategy C/E Bell decided on and implemented that night. He very well may have done as you suggest. We just don't know. But consider this. Andrews told Capt. Smith that he believed the ship had from 1 to 1.5 hours left. This apparently ocurred while Smith was on his personal inspection of the ship some time after midnight. He was back on the bridge by 12:25 since that was time the order was given to load and lower the boats. We know the ship lasted for 2 hours 40 minutes from collision time. It may very well be that Bell put the greatest effort of the pumps in working on the 5th compartment which was BR 6. Once the water level in the first 4 compartments would reach the waterline those compartments would not take on any more no matter how large the openings to sea were. Any stress caused by them being flooded would have reached its maximum at that time. The problem was how to get ahead of the flooding in BR 6 no matter if it was caused by initial flooding damage or stress induced damaged. If the pumps could have kept ahead of the flooding there and the small amount of flooding in BR 5, the ship would have likely remained afloat barring some other catastrophic failure. The maximum pumping capacity was 1700 tons per hour. This is equivalent to an opening of about 60 square inches under a pressure head of 25 ft. Not enough to save the ship, but if you wanted to do something, your strategy makes the most sense to me, and it may have been what was actually done.

 

[Kelly Anderson]

Erik,

I am not talking about saving the ship, I have no doubt that she was doomed, but it MIGHT have been possible to keep here afloat long enough for Carpathia to arrive.

Indeed, no one can speak to how long a particular bulkhead may hold, there are too many variables.

I realize that removing weight is a completely unorthodox method of dealing with a sinking ship and in most cases is mute due to the extent of damage, weather conditions, the inability to remove a significant amount of weight quickly, etc. However, the manner in which Titanic sank is also completely unorthodox due to her being so close to not sinking, as well as the Atlantic being so calm that night that there was no wave motion induced stresses being inflicted on the ship.

I have no information regarding the normal water capacity of one of Titanic’s boilers, so I’ll pull a number out of thin air and say one boiler held 15,000 gallons. If they blew twenty boilers dry, that would have lightened the ship by 1250 tons, not an insignificant amount. You have a point about stability, and it’s a good question as to what that would have done to the metacentric height.

Michael,

I have considerable experience with coal fired boilers, specifically on steam locomotives, although I did fire a two furnace scotch boiler once (what a miserable job!). It is entirely normal for a boiler that was working at full capacity to lift the safeties for upwards of an hour when suddenly stopped, until that heavy, hot fire burns itself down, or is pulled. I also know for a fact that a boiler filled with 2000 gallons of water at 200 PSI can be blown dry in ten to fifteen minutes through a 1-1/2” blowdown valve. Its all a matter of proportion, what was the capacity of Titanic’s boilers versus the size of here blowdown plumbing?

I personally doubt the seriousness of the structural damage to the basic fabric of the ship. Riveted joints are quite easy to spring to the extent required to cause the leakage that resulted. Through the majority of its length, one would have been hard pressed to stick ones fingers through the gap between the plates. Hardly the equivalent of focused damage experienced by the USS Samuel B Roberts as the result of the mine explosion.

As I said in my initial post, this is Monday morning quarterbacking at its finest with 96 years to consider alternatives, where the people on the scene would have had about 10 minutes. The idea of blowing the boilers dry is so far outside the box that it isn’t even in sight, but it is a tool that they possibly could have used, had they been able to implement it, and IF it would have raised the fifth bulkhead one inch above sea level, it MIGHT have bought the ship some more time.

 

[Michael H. Standart]

>>although I did fire a two furnace scotch boiler once (what a miserable job!). <<

I have no doubts about that.

>>Its all a matter of proportion, what was the capacity of Titanic’s boilers versus the size of here blowdown plumbing?<<

Perhaps but that's not quite what I was speaking to. Whether or not the safeties lifted spontanously or were lifted deliberately, they fact is that they were lifted. It happened and the ship still sank in the time that she did. Perhaps if they didn't, the boilers would have gone KABOOM or the ship would have gone down faster, but there you are.

>>I personally doubt the seriousness of the structural damage to the basic fabric of the ship.<<

Insofar as the ship broke up, I don't.

It really depends on the sort of stresses imposed on the hull girder ex post facto to the collision as water flooded in and the after end was lifted clear of the water with nothing to support it as well as the damaged structure's ability to handle all this. This is the secondary damage I spoke to. This is something that would have happened as an on going event and it's not as if such occurances are unknown. The Unfortunate Samuel B. Roberts is an example of that.

It helps to know that it's not just poking holes into the hull were talking about but quite possibly and indeed highly probable massive structural damage incidental to a grounding/allision event with the iceberg.

 

[Kelly Anderson]

>>Perhaps but that's not quite what I was speaking to. Whether or not the safeties lifted spontanously or were lifted deliberately, they fact is that they were lifted. It happened and the ship still sank in the time that she did. Perhaps if they didn't, the boilers would have gone KABOOM or the ship would have gone down faster, but there you are.>>

The safeties lifting is not going to effect the weight of the ship to any degree. A quick calculation shows that 30 minutes of the safeties lifted would dispose of 136 tons of water, a little more than 1/10 the weight I am talking about. Steam is light, water is heavy. Blowing the water out of the bottom of the boilers would have shed a lot of weight very fast.

>>It really depends on the sort of stresses imposed on the hull girder ex post facto to the collision as water flooded in and the after end was lifted clear of the water with nothing to support it as well as the damaged structure's ability to handle all this.<<

True, however this didn't happen until the final moments of the sinking. That time might have been delayed by lightening this ship. Perhaps with weight removed from the waist of the ship, the waterlogged bow would have broken of below the bridge.

 

[Michael H. Standart]

>>Blowing the water out of the bottom of the boilers would have shed a lot of weight very fast.<<

Possibly. They may well have had reasons for not doing this.

>>True, however this didn't happen until the final moments of the sinking.<<

Actually, the exact opposite appears to be the truth. If you have a chance, take a look at the finite point stress analysis that was done by Gibbs and Cox and presented on "Titanic, Answers From The Abyss." This wasn't an All Of The Sudden sort of event but something that happened progressively over time only to snowball at the end. If anything, the situation may have been vastly worse then what Gibbs and Cox presented since they appear to have assumed a hull with no structural damage.

In grounding/allision events over anything, including ice shelves, you will have structural damage.

 

[Samuel Halpern]

A reminder. We really don't know what damage control was done by Bell and his men. Can anyone say that they didn't blow out some of the boilers?

 

[Michael H. Standart]

>>Can anyone say that they didn't blow out some of the boilers?<<

I can't. Unfortunately, the people in a position to know didn't live to tell the tale. If they did this, I would suggest that not everybody got the message. Who was it that found nothing in the sight glasses of the boilers in BR#5 even with the fires still burning? If these boilers had been blown down, it might just explain why this happened.