The Wreck's condition

I just thought about this, but why did the back end of the bow collapse downward, and why did the stern's sides blow out?

 

This is all most likely due to the nature of the breakup. Especially in regards to how the hull plating is pulled outwards on the stern.

 

I don't see why the bow collapsed downward still, nor why the stern's sides exploded outward.

 

During the breakup, the sides of titanic most likely pulled outwards and detached from her double bottom. I'm sure there are more technically sound people here that can give a much more detailed description of what took place. The aft end of Titanic's bow had nothing to support it after the break up. For it not to collapse downward, would defy the laws of gravity.

 

James Cameron’s 2012 Final Word simulation shows how the wreck got to the way is it today. The documentary focuses heavily on the condition of the wreck and some on the exact physics of the sinking. Here’s a quick summary of the the team’s findings:

 

Well one key reason the end of the bow buckled down was on fact due to the nature of the breakup and another key factor "the down last effect" After the Titanic (the bow at least) left the surface it was basically to travel at cruising speed. At least until it hit the bottom. Think of dragging your flat and straight down to the bottom of a tub. When you hit the bottom I can assure you you will feel a "gust" of water come down on your hand. No Imagine this times a near 33 thousand ton section of ship. Imagine how much more of an effect it would have. In a way when the bow hit another"bow" crushed on top of it. And the already fragile section"area around the breakup" felt the brunt of the blow. When the water blew down on it it pushed it down after which it then collapsed.


Now the stern is a slightly different story.
Things are pretty much the same except for one small detail. The stern imploded. This simple action doomed the stern to a horrible fate. When she imploded it didn't not only force things of the ship and blow back the poop. But essentially pushed the hull of the ship aswell. Weaking the structure significantly. And of course during the decent. She suffered unimaginable damage the Deck house ripped off. Nearly the entire area before the fourth funnel lost to Sea. And also because when the stern hit it was most likely at a less angle than when the bow hit. And unlike the bow which kept most of it's structural integrity the stern lost nearly all of it. The hull was in a way hanging on by a thread and the fact that her insides were basically ripped out hardly helped her cause. So when she eventually hit bottom the blast effect on her hull was far more extreme than the bow. I.e them blowing out.

 

Never really understood the downward blast effect. I haven't seen any other wrecks that were damaged by this effect, and it does sound odd that this downward blast successfully followed the ship more than 2 miles down without dispersing or being carried away by the strong deep sea currents and managed to damage both broken ends of the wreck and nothing else, not even the debris field which appears to have gently touched the sea bed without any disturbance and shows no signs of being forced down or embedded deep into the sand. Curious if any other shipwrecks show any similar effects. I assumed the documentary team were basing their theory by looking at other shipwrecks. Is it just a hypothesis that they went along with?


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Isn't most of the implosion damage limited to the very aft end of the stern. I can't remember where exactly but I believe most of the damage forward was a result of the break up.

 

Sure most of the air was expelled with force from the

well sure most of the air was expelled with force from the aft end of the stern but such a violent event would rack it's way through the entire ship

 

I always thought and believed that most of the debris around the stern and throughout the field came not when the three main peices hit but over the following minutes then lighter material could have taken as long as 30 minutes to reach bottom given the blast time to his the bow and stern and the following debris the effect of simply falling like a feather to the sea floor. It's all a matter of how long it took for each object to reach bottom.

 

I think if it was as terrific as the documentary shows then it would have pulled everything down with it in a kind of vortex and pulled the lighter objects down with the wake of the ship and slammed against the wreck when it hit the bottom or at least dug deep into the sand after being carried down with the momentum perhaps at great speed. Strange that the currents did not weaken or disperse the downward blast after 2 miles descent. Really curious to know if other shipwrecks show signs of a downward blast.

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I can't find anymore wrecks that show damage like Titanic perhaps because of the unique circumstances in which Titanic sank. Her distance from the surface and she actually landed right side up. The closets I could find was the Andrea Doria but most of her damage was simply age. And rot. Titanic is alone as far as I can tell in it's unique damage

 

There are a number of factors, and the engineers who are here (I know there are some) can answer much better than I. While the nature of the breakup on or near the surface has something to do with condition of each section of the ship, most of the damage--at least the damage not related to the deterioration of the hull after more than a century in salt water--is due to hydrodynamic forces involved during the sinking.

For example, much of the damage to stern is the result of implosion damage, which was severe. This was made even worse by its plummet through two miles of sea water and its impact on the bottom. That impact both forced water explosively out of the wrecked portion of the stern AND was accompanied by a down blast of water trailing the ship as she sunk.

These forces combined to give the stern the appearance of explosive damage, when in reality all of the damage was caused by the initial implosion and the following hydrodynamic effects.

The bow, on the other hand, being more full of water when she sank, suffered very little implosion damage. Therefore, while she certainly did suffer some damage during the fall to the sea floor (like the collapse of the forward mast, and possibly the stripping of the parts of the superstructure) most of the observable damage was caused by the impact itself, except for that down burst of water... which bent the already weakened (and probably already bent to some extent) deck plating near the break downwards.

 

I just noticed something that may help explain why the back end fell down! If you look closely at the simulation, you'll see a piece of the back end is missing! That would of helped to weaken the structure!

EDIT: I wonder why the Titanic has not already rotted away..

EDIT2: When did the forecastle deck go under?

 

Most other wrecks do not involve the same hydrodynamic effects. For example, most major liner wrecks are in water that is shallow enough that part of the ship impacted the ocean floor prior to the entire vessel going underwater, or the ship in question did not achieve its terminal velocity in water.

Titanic on the other hand did achieve its terminal velocity, and was sinking at somewhere between 30 and 45 knots. I am not a physicist, and am not super versed in fluid dynamics, BUT... as simply as I understand it:

An object falling in water causes a slip stream, just like an object flying through the air does...

This is because the gas or fluid rushes in to fill the space previously occupied by the object moving through it. The speed and force of that gas or fluid is relative to the properties of the medium (water in the case of Titanic) and the speed at which the object is moving.

Any given person has probably experienced this phenomena first hand many, many times during their lives. For example, standing street corner one can feel buffeted by the air if a car speeds through the intersection. This is because the car is displacing the air on all of it sides, and the air is rushing back in to fill the vacuum left by the volume of the car. You can feel this yourself if you get close to a fast moving object, like a race car on a racetrack.

In any case, the fluid dynamics of water mean that if an object is traveling at 30 mph through the water, the trailing fluids would be reacting as if you were traveling at 1,250 mph (nearly twice the speed of sound) through the air.

Now someone might object, "but modern submarines move through the water at this pace all the time!"; however, in the case of a submarine, these hydrodynamic effects are mitigated by a number of factors including:

• The submarine does not have exacerbating structural damage; and
• Submarines, hopefully for the crew on them, are not coming to a sudden and complete stop from maximum seed.

In the case of Titanic, which was falling towards the sea floor at somewhere between 34 and 51 miles per hour, the ship had already suffered significant structural damage during the breakup, implosion of the stern, and fall to the sea floor. On top of this, both parts of the ship come to a catastrophic halt from the above speeds the moment they hit the sea floor. This means that the hull will be exposed to the full downward force of the trailing water column moments after it comes to a halt.

 

I've posted this somewhere else on this site (can't remember where or when, but recently) concerning the case of the "Sleipner A" semi-submersible that sank in the fjord off Stavanger, Norway. The structure, weighing some 800,000t if I remember correctly, reached a considerable velocity sinking through 210m to the bottom of the fjord, where it struck the bottom and occasioned an earth tremor of some 3.1 on the Richter Scale, which broke windows and caused structural damage to houses along the fjord-side. An inspection of the wreck following the sinking showed no pieces larger than a fist, so any salvage was abandoned. Whilst the structure was mainly concrete, it does show what forces are involved in sinking only a short distance.
Sleipner A - Wikipedia