Did the Titanic have to sink?

Discussion in 'Stability' started by johnben, Apr 13, 2012.

  1. johnben
    Joined: Apr 2012
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    johnben New Member

    Hi Folks I am new to the forum, In honesty I have never designed a boat, I mess about in sailing boats and I worked on the River Thames in charge of the fire boat for some years and I design a raft each year, not very well, for a charity race but that’s about it.
    I have a theory on the sinking of the Titanic, I have hawked it around a few Titanic forums but have not yet received the killer blow. I would appreciate your views, sorry about the length of the article.
    John

    An alternative view.

    At 11.40pm on Sunday 14 April 1912, travelling at over 22 knots, RMS Titanic on route to New York struck an iceberg. She sank less than 3 hours later with the loss of more than 1,500 lives, almost two-thirds of the people on board. It is now the centenary of the event and most have concluded that nothing else could have been done to save the ship and avoid the large loss of life.
    There has been much debate as to whether the ship should have hit the iceberg head-on thus reducing the number of compartments damaged or whether better use of the ships engines and rudder would have resulted in a near miss.
    For the purpose of this article the Titanic has hit the iceberg as history recorded. My alternative view on the tragedy is that once the iceberg was hit and it was known the vessel was seriously damaged and taking on water, the order should have been given for full speed astern and astern propulsion should have been maintained for a long as possible. I suggest that this course of action may have saved the ship and in any event would have bought time, allowing the lifeboats to be better organised and passengers to have spent less time in the freezing water before rescue.
    The design criteria of the vessel was that she would remain afloat with four compartment ruptured, the damage inflicted by the iceberg ruptured 5, however, these compartments did not fill with water immediately and it is this time whilst water was pouring in which, presented a window of opportunity in my view to save the ship or at least prolong her survivability.
    During her sea trials in the Irish Sea the Titanic performed an emergency stop from 20 knots in less than half a mile (ref: The last log of the Titanic By David G. Brown). At the time of the collision she was doing a little over 22 knots so we can guesstimate that if the order had been given after the collision that within 10-15 minutes she would be moving only slowly forward or building up speed going backwards in the water, time is critical as we know that her propellers were coming visible within 50 minutes as she took on water and all effective propulsion ahead or astern was lost.
    However, in my scenario this time would be extended as the vessel slowed and the intake of water was lessened. Two of her three engines were capable of reverse thrust; the centre one was forward thrust only. By going astern the more (by now) buoyant stern end would have the effect of trying to draw the sinking bow out of the water to a more level angle and reducing the huge inflow of water. By going astern with the rudder over to starboard would result in the vessel’s stern turning to starboard on a circuitous course. This would have the effect of increasing the water pressure on the undamaged side and reducing the pressure on the damaged side further lessening the ingress of water.

    I have searched the Internet and found nothing in support of the above viewpoint, I am therefore curious for an explanation and apprehensive that the explanation has been obvious to everyone except me.

    John Bennett

    I have received some replies which I have listed below so as to save repartition:

    by Michael » Thu Apr 05, 2012 4:36 pm
    I don't believe the propellers started coming out of the water until about 12:30 am and weren't fully out until around 2:10 am. The scenario you proposed wouldn't have delayed the sinking, but might have actually hastened it and it would have made it impossible to launch any lifeboats. The rate at which the water came in was connected to the displacement of the ship, not completely, but to a large degree. Reversing the ship wouldn't have made it any lighter, but it could have increased the pressure around the hull by the water flowing past and might have increased the rate at which it entered the ship.

    Reply by John Bennett

    Thanks for the response and the correction in time as regards the propellers being exposed, do you know how long the emergency stop had taken in the Irish Sea?
    Regarding your view that going in reverse would hasten the sinking of the Titanic, I disagree, the 6 slits of damage were all on the curved area of the hull. Going forward, water would be forced in not only by sea pressure but also the forward movement of the vessel, when stationary the sea pressure would ensure that water poured in, however, in reverse the shape of the hull would increase the Venturi effect and reduce the pressure in that area. As regards launching the lifeboat the vessel could come to an emergency stop quicker than normal as she would only have two of the three propellers working plus the stern of the vessel is very much less streamlined then the stem. As regards displacement of the ship the effect I was trying to describe is that of an object with a positive angle of attack and given sufficient momentum will rise, perhaps a rather inappropriate example would be a submarine, which uses it’s sail planes to ascend and descend. I have been unable to find out what the astern speed of Titanic was but I would guess between 8 – 12 knots, it’s hull was at an angle as the bow filled but whether the speed of the vessel going astern could have provided enough lift to reduce the ingress of water I don’t know.
    John

    by sam halpern » Fri Apr 06, 2012 12:29 am
    A moving ship creates a positive pressure field beginning about 1/6 aft of bow and forward, a negative pressure field between about 1/6 aft of the bow to 1/6 ahead of the stern, and another positive pressure field from 1/6 ahead of the stern and aft of that. The actual field itself and the exact neutral points depends on the hull shape. Unfortunately, the change in pressure due to movement compared to the static pressure at a depth of 25 ft below the waterline where most of the damage was in any event would be relatively small, and would not change the inflow flooding rate by an amount that could possibly have saved the ship.
    Sam

    Thanks for the comments regarding the pressure zone, which I agree exist in the area surrounding a normal undamaged vessel under way on an even keel. Your final comment ‘and would not change the inflow flooding rate by an amount that could possibly have saved the ship.’ Seems to indicate that you consider that even if the course of action I had suggested had been taken that the Titanic travelling at some speed at an abnormal stem to stern angle and going astern would have made little difference to the outcome either in the sinking of the vessel or the time it took for this to happen.
    I am not an expert on any maritime subject but it seems that such a dramatic alternative action not affecting the time frame (positive or negative) would be surprising. My original theory revolves around the angle of the hull and the effective transfer of damage from the starboard front bow and an area beyond to the aft area, (as the vessel would now be moving in the opposite direction).
    We know that objects heavier than water such as water skiers, windsurfers using sinker boards, swimmers and submarines (depending on ballast) all use an angle of attack and forward movement all at very low speeds initially to make a difference to their apparent buoyancy. Though there is a colossal difference in their size and that of the Titanic, I am not aware that this principal breaks down because of this, plus the fact that the Titanic was still buoyant. If the Titanic was going astern at sufficient speed and angle of attack she would not sink. What this speed is and if it were possible to achieve I have not got a clue, my premise is that whilst she had astern propulsion and was higher aft than forward it must have made some difference and I am still convinced that this action could have extended the time frame and thus have saved more lives if not the survivability of the ship.
    Lady Pattern's book, Good as Gold, reveals that and I quote; “for ten minutes, Titanic went 'Slow Ahead' through the sea, which added enormously to the pressure of water flooding through the damaged hull. The instruction lead to the sinking of the Titanic many hours earlier than she otherwise would have done by forcing it up and over the watertight bulkheads. 'The nearest ship was four hours away. Had she remained at "Stop", it’s probable that Titanic would have floated until help arrived."

    I don't who done the analysis but I have included it to show that there are other views on the sinking.
    Surly someone must have replicated the situation using a large model and gone through all the alternatives, if anyone has any information I would be grateful if they would pass it on. Failing that I will have to try and do it myself just to put some sought of closure on it for my own curiosity as regarding my reverse theory.
    Thanks
    John Bennett
     
  2. The Loftsman
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    The Loftsman The Loftsman

    Interesting theory but would have to say that in my humble opinion the vessel was doomed by the main participants being onboard (the owner of White Star Line etc) all looking over the captains shoulder and telling him they must get to New York faster.
    Yes with hindsight it is easy to see that many decisions were wrongly called, it is not really a question of would she sink or not but of how quickly decisions were made to get as many people into the too few lifeboats as possible.
    When a vessel in excess of 80,000 tons hits an immovable object such as an iceberg at any speed never mind close to 20 knots (same as hitting rocks) then the forces involved are colossal and steel no matter what quality is like tin to a tin opener when this happens.
    So would going astern have helped, don’t think so as it if successful would only have prolonged the ships passengers agony as the decision to abandon ship would have been the same but perhaps half an hour later.

    Cheers
     
  3. Petros
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    Petros Senior Member

    I have read extensively about the accident, both before and after the wreck was discovered. Any number of just a single decision done differently might have prevented the massive loss of life. But disasters are like that: not one bad choice, but a series of bad ones that by themselves were not fatal, but taken together prove otherwise.

    The boiler room was flooded from the beginning, so I do not see how there would be any power to the propellers. Hitting the ice burg straight on at 22 knots would have sunk her faster I suspect, the hull would have slit and sank, more people killed. I think it is folly to think hitting it head-on would have been a good idea, and there is no way any crew would have made that decision after they spotted the ice burg anyway.

    One little detail that I read about that never gets discussed was about the steel used in the hull. It was not discovered until the wreck was located and samples brought up and tested; the supplier substituted a different alloy because they likely could not deliver the quantities required in time of the ordered material. It had the same strength, but was more brittle than the alloy specified. That caused the bulkheads to rupture on impact rather than deforming. That alone could have prevented the disaster. I suspect also that is why it was such a surprise that the hull broke in half when it sank, that was not even suspect until after they located and examined the wreckage decades later.

    But ramming an ice burg with a brittle steel hull is not likely something that would have worked.
     
  4. Submarine Tom

    Submarine Tom Previous Member

    It was a "perfect storm" for disaster.

    I'd say they were pushing the odds and lost.

    Happens all the time to one degree or another.

    Of course leaving port on a Friday could have been a factor but Friday the 13th!!!
     
  5. hoytedow
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    hoytedow Wood Butcher

    Don't forget Apollo 13 was launched on April 11 at 13:13. :eek:
     
  6. Submarine Tom

    Submarine Tom Previous Member

    "We have lift off!"


    "Houston, we have problem..."


    "The Eagle has landed."
     
  7. MoeJoe
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    MoeJoe Junior Member

    Guess that if Titanic would have gotten into full reverse towards nearest ship it could have helped resque assistance. I'm not surprised really that there were insufficient safety equipment and rescue routines 100 years ago. Altough even then there were warnings. Pride and ignorance created the disaster I guess.

    I was perhaps more surprised of all flaws and bad judgements when M/S Estonia sank in the Baltic Sea in 1994. E.g. insufficient controls of made repairs, too high speed in high seas, no camera/visibility for bow from wheelhouse, no proper system for other cruisers in the area to pick up survivors (They improvised instead), etc
     
  8. Submarine Tom

    Submarine Tom Previous Member

    With the recent events of the Costa Concordia it seems little has changed, that we really haven't learned a dam thing. Well, at least some of us haven't.

    Did the Titanic have to sink as the OP asks:

    Yes

    Was it a worth while learning experience?
     
  9. SheetWise
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    SheetWise All Beach -- No Water.

    I could never figure out why they didn't just stay with the iceberg, it could have served them as a life raft -- at least some of them.
     
  10. johneck
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    johneck Senior Member

    I can't think of any reason that going astern would help with flooding. It would definitely have prevented launching any lifeboats. As it was, they had plenty of time to get people into the boats, but didn't do a very good job filling them.
     
  11. Squidly-Diddly
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    Squidly-Diddly Senior Member

    I think going astern would have used dynamic pressure to keep the bow from

    continuing to drop, or at least drop as fast.

    Interesting.

    Yeah, I always wondered about the iceberg as floating island.


    Also, why not empty every champagne bottle and jam jar and use some of that Edwardian lard based cuisine to make oil-skins out of some of the drapes and ultra-king sized bed spreads and create a volume out of chairs and tables and thus make "corticals", since the sea was so calm all you had to do was float above water.

    I'd imagine thick curtain soaked with hot lard would become water resistant enough when exposed to near freezing water to make a vessel seaworthy enough to be kept afloat by vigorous bailing.

    Turn over a large table onto a even larger water-proofed theater curtain and cover the underside of the table with whatever chairs lended themselves to being lashed together to form freeboard the height of the back of the chairs. I'm thinking about a 12' long, 5' beam and 3+' tall sides.

    But either would have taken over an hour and "management" didn't want to panic the condemned.

    But I bet if they had just crudely lashed a lot of wooden furniture to gather they could have saved hundreds.

    The boats that only held less than 1/2 capacity refused to return fearing it would only become a brawl and everyone would be lost, but they might have been able to collect small manageable numbers of people off makeshift rafts.
     
  12. PAR
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    PAR Yacht Designer/Builder

    The ship survived quite well considering the damage and design. The spiral of errors that occur before every major catastrophic lose of life, is always easy to second guess when you're reviewing them in hind sight.

    Most of us just can't possably relate or understand the attitudes and sensibilities of the era, so rational thought with 21st century hindsight is just inappropriate. The skipper did what was expected and usual, for someone in his position and of his status. Speculation as to keeping the water tights down or not and other ridiculousness, doesn't take into account that several factors where in play, such as the indisputable designer and owners aboard, insisting on certain things. The simple fact that the ship stayed afloat as long as it did, is testament to how well designed and built she actually was.

    Yes, the event had and needed to occur. It would have been nice if so many needn't lose their lives to prove the falabilities of the era, but would the lesson have been learned if they hadn't?
     
    SheetWise likes this.
  13. Bengo
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    Bengo New Member

    Hi John,
    I know yours is an old post, but I found this page tonight precisely because I was wondering exactly the same thing as you did, and I have to say the replies you got here do not seem to do your suggestion any justice at all.

    For starters, the director of the Titanic film, James Cameron, who has played an active part in investigating the disaster has in fact posited the same theory in one of the Titanic wreck documentaries, though to the best of my knowledge he has not yet published a documentary on the theory.

    Many things were done on the night to prolong the ship's life, not least the heroic efforts of the crew, many of whom battled hard to keep the ship afloat, even pumping out water until the last possible moment. As the film shows, however, some boilers were also kept lit until the last few minutes, and forward power was certainly available after the iceberg was struck (the iceberg passed the ship at a rate of knots and departed into the night. No hope of using that).

    I am not a boat designer either, but like you I cannot see why throwing the two reversible propellers into reverse would have produced no upthrust whatever. Any upthrust would have lightened the ship and must certainly have delayed the sinking. The only question is "by how much". Now I have to say that whatever the reversing speed of the ship - and we can find out - the angle of the ship - front down in the water - would have reduced it. Logically, however, it would not have reduced the amount of upward thrust of the propellers, and the initial angle of the ship in the water could not have stopped the ship from travelling backwards altogether.

    Studying the ship's design, it had a flat bottom for a considerable proportion of its length, and it is difficult to see how the ship moving in reverse could possibly fail to provide upthrust as the flat bottom planed over the water. Any backward movement, would have to result in upthrust, and there are formulas for calculating this from the area of the ship's flat bottom and the speed achieved. Just don't ask me to do it.

    Even without this effect, the ship in fact stayed afloat for two hours and forty minutes and help arrived at the scene only an hour and twenty minutes later, so the sinking had only to be prolonged by 50% for more folks to have been saved. This might sound a lot, but any way the ship's prow could be raised, or its sinking slowed down during the early part of the sinking - with boilers still lit and thrust available - would have kept the ship afloat exponentially longer than the same power later.

    If by some chance, the thrust at, say 10 knots were sufficient to arrest or delay the entry of the prow into the water, then the gashes in the side would be irrelevant, because water only enters the ship to equalize the levels inside and outside. Water would reach a certain level inside the ship and then stop coming in no matter how big the holes were - unless the ship were travelling so fast that the water was forced in to the holes by the sheer speed of the ship - hardly the scenario here. It wasn't a speedboat. Even if it had been, only enough extra water would enter the gashes to equalize the water pressure and when it got to a certain level the water could no longer come in because the pressure of the water inside the ship would prevent that. The gash might stop the ship from being dragged out of the water so far that the ship was level, but would not drive the prow deeper. It would simply make the front of the ship find its own level and stay there so long as the backward speed was maintained.

    The only question for me - until a physicist/mathematician proves otherwise - is what speed they could have made how soon and for how long. And how much thrust would it have taken to delay the sinking for one hour and twenty - not whether it could have been delayed at all.

    Thanks for the interesting info about how long the props were submerged. For what it's worth, I believe we both have a point, and you definitely were not the only one to entertain this possibility. More to the point. If you were the captain, you would at least have had to try.
     
  14. Mr Efficiency
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    Mr Efficiency Senior Member

    Ah, no. There is no planing action, you are talking massive weights, low speeds, and the "loading" on the flat bottom way too high. It came to grief for a host of reasons, probably none more important than the reluctance to reduce speed. When you hit heavy objects at speed, things break.
     

  15. latestarter
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    latestarter Senior Member

    I shall try to add some figures to the debate on the uplift due to the 2 reversible propellers.

    Titanic’s dimensions:-

    Displacement 52,310 tons

    length 882 feet

    reversible engines 30,000 bhp

    On pages 1 to 3 of this paper it is calculated that a ship travelling at 20 knots requires 6960 bhp to produce 40 tonnes of thrust.

    https://s3.amazonaws.com/zanran_storage/teaching.alexeng.edu.eg/ContentPages/47219716.pdf


    Assuming Titanic’s drive system and propellers in reverse were as efficient as a modern ship’s going forward, the thrust available would have been 40 x 30,000/6960 = 172 tonnes

    If the bow was down say 20 feet relative to the stern the angle of the ship would be 1.3 degrees.

    The vertical component of the propellers due to the inclination of the ship would be 172 x sin1.3 = 3.9 tons.

    So the effect would be the same as chucking a couple of large cars overboard.

    Or have I put a decimal point in the wrong place? :D
     
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