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[cos918]

found these links. And after reading them makes intresting thinking.

john

http://www.nytimes.com/2008/04/15/science/15titanic.html?_r=2&hp&oref=slogin&oref=slogin

http://www.independent.co.uk/news/uk/this-britain/titanic-doomed-by-fire-raging-below-deckssays-new-theory-808472.html

[Bryan Young]

found these links. And after reading them makes intresting thinking.

john

http://www.nytimes.com/2008/04/15/science/15titanic.html?_r=2&hp&oref=slogin&oref=slogin

http://www.independent.co.uk/news/uk/this-britain/titanic-doomed-by-fire-raging-below-deckssays-new-theory-808472.html

Re. the rivets: makes one wonder if other, less publicised, sinkings could be blamed on the rivets. "Titanic" and her sisters were obviously not the only large ships being built at the time....otherwise why the shortage of material. If that is the case, then I do wonder how many more lives were lost from the same cause. Ref. the bunker fire, the subject of coal-bunker (and coal cargo) fires was always given a lot of time at Marine College. I also seem to recall that putting water in to douse a fire would only exacerbate the problem as the water would turn into steam and perhaps blow the whole shebang into little bits. The only solution was to dig it out..."inert gasses" were unknown then. (in this sense). One has only to check on how many closed coal mines or spoil heaps have had fires raging for donkeys years.

[Bunkerbarge]

There remains to this day split opinions on how to deal with a scavenge fire.  If the fire is hot enough admitting steam smothering can flash off, break down into hydrogen and oxygen and significantly feed the fire.  How do you know whether it is hot enough?  I hope I never have to make the decision!

[Colin Bishop]

The rivets issue seems to be an offshoot of the "brittle steel" theory. However I would have thought that contact between a ship the size and speed of Titanic with hard unyielding ice would inevitably have "popped" rivets and opened seams regardles of their "quality". If Titanic had rammed the iceberg head on she would probably have survived. As it was, the lacerating broadside contact simply opened up too many seams and compartments for the water ingress to be controlled. Not rocket science really and no special theories are required to explain the consequences.

In those days bunker fires were not uncommon and it is unlikely that this one materially affected the loss of the ship.

Colin

[Martin (Admin)]

I always thought it was the quality of the iceburg that caused the sinking of the Titanic....  ::)

[Bunkerbarge]

I must admit over the years the various theories put forward as regards the Titanic sinking have more to do with advancing individual carers rather than sound naval architectural or engineering thinking.

As Colin says the ship hit a very large and relativelty imoveable object and gashed a hole along the side thus breaching a number of vertical compartments.  Why rocket science is required to prove why it sunk completely escapes me.  If you did exacly the same with a modern ship the same would happen, whether it was welded, riveted or held together with chewing gum!  It was the fact that it breached a number of compartments that did it and nothing to do with steel quality or riveted construction. 

In fact I wouldn't be surprised if shell construction is quite a bit thinner nowadays, I have been involved with corrosion through hull steel a couple of times and believe me it wouldn't take much to puncture a hole through it.

[Colin Bishop]

Bunkerbarge,

I think you are right about shell plating thickness. I understand it is typically quite a bit thinner than it used to be at the turn of the last century. on the other hand I suspect the quality of steel these days is rather better!

The basic sitiation is that, in a collision, you have umpteen thousand tons bearing down on plating which is less than an inch thick. The result is inevitable. It will rupture. The critical issue is restricting the flooding to a limited number of compartments so that the ship remains afloat.

Colin

[Martin (Admin)]

Due to Titanic's "poor handling", where any of her sisters re ruddered or changed in any way?

[Colin Bishop]

I don't think so Martin. Remember, in those days large ships weren't expected to be especially maneuverable. On leaving port there would be a fleet of tugs to chivvy them and point them in the right direction and another fleet of tugs to receive and dock them at the other end. They weren't expected to do body swerves in mid ocean!

In the case of the Titanic the officer of the watch was faced with a bit of a dilemma. He chose to put the engines astern to slow the ship but that reduced the propwash over the rudder and reduced its effect. He could have continued ahead to maximise the rudder response but he would then have reached the iceberg sooner so he was probably caught either way. With hindsight, if he'd just hit it head on the ship would probably have stayed afloat, albeit a bit shorter, but that would hardly gave been a natural reaction.

The basic problem was that the ship was going too fast for the conditions. The absence of binoculars in the crows nest probably didn't help either.

Colin

[Martin (Admin)]

Is it documented anywhere how long between spotting the iceburg and the collision?

[Colin Bishop]

37 seconds apparently. Not enough time to change their trousers...

Some interesting info here: http://www.encyclopedia-titanica.org/articles/man_collins.pdf

[Bryan Young]

Due to Titanic's "poor handling", where any of her sisters re ruddered or changed in any way?

Why would you want to "re-rudder"? Please do not let me think you have fallen into the "trap" postulated in the "Titanic" film. All of the so-called "experts" were so quick to say that "in the old days" turning to port meant turning the wheel to starboard. Stuff and nonsense. OK if you are using a tiller (as in a yacht), but not on a ship. All of this "crap" came about because the film maker only made one half of the ship and reversed the images to make one side of the ship look like the other. So the actors buttoned their jackets the "wrong" way around etc. and made it all look quite presentable. Until it came to the crunch (as it were), when the guy on the wheel when given the order "hard-a-port" did so. But when the film was reversed he was, of course, shown to be turning the wheel to starboard. A serious lapse in continuity that has led to all sorts of arguements that had no basis in fact, just a lapse in the film making process. Stupid, really. BY.

[Martin (Admin)]

No, I just thought someone may have decided to fit bigger rudders to similar ships in case of similar emergencies.

[dougal99]

Bryan

You should get out more    I watched Titanic and remember it as a film about some girl in a wet blouse, oh and something about a ship sinking. 

Doug

[Bunkerbarge]

Bunkerbarge,

I think you are right about shell plating thickness. I understand it is typically quite a bit thinner than it used to be at the turn of the last century. on the other hand I suspect the quality of steel these days is rather better!

The basic sitiation is that, in a collision, you have umpteen thousand tons bearing down on plating which is less than an inch thick. The result is inevitable. It will rupture. The critical issue is restricting the flooding to a limited number of compartments so that the ship remains afloat.

Colin

Colin, Interestingly enough I share the views of a number of sea going engineers who actually believe that steel quality is considerably lower than it was a hundred years ago.  The reasoning for this thinking is that traditionally steel was smetled from raw ore of a considerably higher quality than it is now.  Chemical testing was crude to say the least and it was certainly open to chance but basically you got what the ore gave you.

Nowadays the chemists have got it all down to a fine art and although there are pre-set requirements and limits to manufacture to the industry nowadays is more than capable of taking the quality right to the edge.  The problems come from all the other elements that modern steel contains which are not regulated and which come from the very high percentages of recycled steel which modern products contain.  The origins of these recycled steels is always questionable but as long as the defined parameters are met the smelted steel is OK for use.

I have personally experienced rates of corrosion in modern steel plating that was quite alarming and to me indicate a quality that is not comparable with much older steels.

[Colin Bishop]

That's interesting Bunkerbarge, I hadn't thought of it like that. Maybe I should have as the "iron" keel of my 1:1 yacht is in fact made up of anything available that was thrown in the pot when melting down the material to put in the mould. As a result there are lots of busy little reactions going on which lead to continuing outbreaks of surface rust which it's impossible to stop altogether although the thickness of the keel means that the effect is just cosmetic in practice.

What you say rather confirms the concern felt in many quarters that sending bog standard cruise ships down to the Antarctic is an accident waiting to happen.

Colin

[Bryan Young]

There remains to this day split opinions on how to deal with a scavenge fire.  If the fire is hot enough admitting steam smothering can flash off, break down into hydrogen and oxygen and significantly feed the fire.  How do you know whether it is hot enough?  I hope I never have to make the decision!

Have you read the report on the hydrogen fire that "Bulwark" had? To tell the truth, I cannot remember exactly which carrier it was...may even have been "Hermes"....but I did see the huge "clinker" that was recovered. Horrifying. Better than anything a car crusher could do.

[Bryan Young]

Bunkerbarge,

I think you are right about shell plating thickness. I understand it is typically quite a bit thinner than it used to be at the turn of the last century. on the other hand I suspect the quality of steel these days is rather better!

The basic sitiation is that, in a collision, you have umpteen thousand tons bearing down on plating which is less than an inch thick. The result is inevitable. It will rupture. The critical issue is restricting the flooding to a limited number of compartments so that the ship remains afloat.

Colin

Colin, Interestingly enough I share the views of a number of sea going engineers who actually believe that steel quality is considerably lower than it was a hundred years ago.  The reasoning for this thinking is that traditionally steel was smetled from raw ore of a considerably higher quality than it is now.  Chemical testing was crude to say the least and it was certainly open to chance but basically you got what the ore gave you.

Nowadays the chemists have got it all down to a fine art and although there are pre-set requirements and limits to manufacture to the industry nowadays is more than capable of taking the quality right to the edge.  The problems come from all the other elements that modern steel contains which are not regulated and which come from the very high percentages of recycled steel which modern products contain.  The origins of these recycled steels is always questionable but as long as the defined parameters are met the smelted steel is OK for use.

I have personally experienced rates of corrosion in modern steel plating that was quite alarming and to me indicate a quality that is not comparable with much older steels.

As most of the "big" ships ploughing the oceans these days tend to be "crude" carriers,...I will ask one question. Is it still true that plate thickness can be reduced by 10% per year (depending on the crude being carried) and that is why old tankers have most problems?

[Ghost in the shell]

if the helmsman had simply ordered the centre engine to idle and the outer engines to full astern, (centre engine is a turbine - non reversing engine), and simply rammed the iceberg, rather than to swerve and try to avoid, I think Titanic would have made new york, albeit 50 to feet or so shorter!

[Colin Bishop]

Yes Ghost, you are probably right but helmsmen don't give orders, it's down to the officer of the watch!

[Ghost in the shell]

and instinct would be to swerve.

[farrow]

Some time ago there was a programme about Titanic sinking and the theory of brittle steel in cold weather arose, as apparently such knowledge was not known when she was built. To test the theory a plate of steel recovered from the wreck site was set up for a shear test at the temperature known in those waters for that time of year, as a comparison a new piece of steel plate produced to go in cold waters was also set up in the same manner. The swinging weight of the force expected was swung and the Titanic plate sheared immediately, the other modern test piece mearly buckled. From this test a theory was put forward that Titanic plates below the waterline shattered and critically the forward collision bulkhead also failed for the same reason.
It is not possible to check this theory on the wreck as I believe the seabed is nigh upto her waterline. But she did break into three pieces on the surface as she started to dive???

[Colin Bishop]

My impression was that she broke in two as she sank. The bow section was waterlogged while the stern section was sticking in the air. No ship is designed to take that sort of stress with a large part of the hull entirely unsupported so I don't thik that was necessarily to do with the quality of the steel.

There seem to be conflicting theories about the brittleness of the steel at low temperatures but I think somebody demonstrated that simply splitting the seams from contacting the iceberg would have been sufficient to account for the degree of flooding, especially as it opened several compartments to the sea.

[The long Build]

. But she did break into three pieces on the surface as she started to dive???

She did break into 3 pieces , this has been proved with the finding of a large section of hull  a distance away , from the main 2 pieces of wreckage.

[Colin Bishop]

I thought it was a third debris field together with large sections of plating That isn't inconsistent with the ship splitting basically in two either at or just below the surface. A couple of interesting sites:

http://www.encyclopedia-titanica.org/breakup-of-titanic.html

http://www.youtube.com/watch?v=pJy6X2noABs There are some entertaining model sinkings associated with this one!

Ships do seem to break up when sinking, many of the larger German surface warships lost their sterns and the bow of the Ark Royal apparently broke away on her way to the bottom.