The Downblast theory

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Paul Lee

Member
Whilst downing one too many Amber Nectars this evening, my mind wandered to the Titanic. As you do.

I recall reading in "Titanic:Destination Disaster" that the wheelhouse structure has been "eaten down to a nub" by the undersea organisms. At the time, I accepted this.

But then, later on in the year "Discovery of the Titanic" was released. Also released was Dr.Pellegrino's downblast theory. This got me thinking tonight:

The wooden structure in front ot the telemotor on the wheelhouse is more or less the same as it was when first photographed in 1986. This means to me that the undersea organisms hadn't paid it too much attention - contradicting the Eaton and Haas theory.

If the downblast theory is correct, then how come the telemotor wasn't blasted away? Alternately, if the wheelhouse was blown away on the way to the bottom, how come the telemotor alone survived? The rest of the bridge instruments survived. Its been said that the falling firt funnel knocked them away, but I have my doubts about that...

The walls of the officers quarters, most notably Captain Smith's bathroom, opened up allowing one to view the rooms, as if a giant fist had stamped them down onto the boat deck. If the downblast theory is true, why wasn't the whole of the officers quarters flattened too?

Off to bed

Paul

 
Michael H. Standart

Michael H. Standart

Member
The telemotor survived because it was very firmly bolted down to the deck. The surrounding structure was swept away because it was wood. I remember the wreck photos taken shortly after the ship was discovered and the deck structures were in much better shape then. What you're seeing now is, in all likelihood, the result of natural deterioration over time.

Personally, I don't put a lot of stock in the Downblast Theory at all, but I'm willing to change my position if some corroberation for it can be found in peer-reviewed scientific papers.
 
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Paul Lee

Member
I'm not too sure. Water is a lot more dense and viscous, and when the ship stops moving as it hits the ocean floor, all that kinetic energy has to go somewhere. Still, if downblast is a viable theory, I would have expected a lot more damage on the upper decks, and possibly some indentation in the sediment (it would also have ripped the D deck entry door off too!).

The only signs of collapse in 1985 were the walls of the officers quarters, the boat deck grand staircase landing and the gymnasium ceiling, which could have collapsed due to erosion and fatigue in the preceding 73 years.

Cheers

Paul

 
Michael H. Standart

Michael H. Standart

Member
>>I'm not too sure. Water is a lot more dense and viscous, and when the ship stops moving as it hits the ocean floor, all that kinetic energy has to go somewhere.<<

It did...right through the hull and into the mud. Take a look at the bow and the way it's bent downwards just forward of the superstructure. It took a lot of energy to make that happen.

If you want to get a sense of how deeply into the mud the bow is embedded, chack out any photo of the ship on the launching ways and take note of just how high above the keel the anchor is. Then take a look at a wreck photo and take not of just how close the anchor is to the mudline. If the downblast theory is correct, I would expect a lot of that mud to be blown away, and as far as I know, nothing of the sort has been observed.
 
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monica e. hall

Member
The effect of kinetic energy is variable depending upon the obstacles (size, density, hydrodynamics etc) in the path of that release. I doubt if anyone could either predict or analyse which structures would have been more vulnerable than others. The telemotor, as Mike says, was firmly bolted, quite small, relatively speaking, and dense. I would have thought it fairly likely that the ship did not dive down and bury her nose, more that she skidded along, gradually burying her bows to a considerable depth. The passage or time and the currents would conceal this, surely. So I don't think we can estimate how much kinetic energy was available for release as a result of the impact. Much of it must have been diffused outward as she came to rest, and what with that and the effects of erosion and bacterial activity ... well .... And currents are continually exposing and burying bits of the wreck, surely?
 
Steven Hall

Steven Hall

Member
Monica I somewhat agree.
I would image the bow coming to a jarring halt would have sheered the mast off and seen it speared over the bow.
 
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Michael Wheeler

Member
Correct me if I'm wrong but the downblast theory says that the ship created a hole of sorts in the water and when the ship came to an abrupt stop all that water came down on top of it. If the bow was planing at an angle then wouldn't any downblast come down on the collapsed decks at the tear explaning their crushed state? Just like the stern came down bottom first any downblast would have hit it on top pancaking the decks and exploding the hull like we see it today.
 
Ryan McKeefery

Ryan McKeefery

Member
I am a firm believer in the downblast theory.
Think about it; if you bring down your hand with force, as if to slap your thigh, and then stop suddenly, you get a breeze on the back of your hand. It's simple physics.
Michael...
I have my own theories on how the bow came down from the surface. I believe that Titanic both planed at an angle, but began to level as she neared the bottom. Check out the link.

https://www.encyclopedia-titanica.org/discus/messages/5664/936.html?1125115837

It's about halfway down the page. A couple of minor flaws have been pointed out since I posted it, but it might be of interest...
 
Michael H. Standart

Michael H. Standart

Member
>>Think about it; if you bring down your hand with force, as if to slap your thigh, and then stop suddenly, you get a breeze on the back of your hand. It's simple physics.
Michael...<<

Then perhaps you would care to dig up some scientific references to explain it in the context of hydrodynamics. Remember that liquid has characteristics which are different from that of a gas, not the least of which is that liquid does not compress. Gas does.

>>I have my own theories on how the bow came down from the surface. I believe that Titanic both planed at an angle, but began to level as she neared the bottom. Check out the link. <<

That's interesting but you'll note that the actual tank tests which were accomplished with an engineers (Referenced in the thread you posted a link to) model don't support that.

>>Correct me if I'm wrong but the downblast theory says that the ship created a hole of sorts in the water and when the ship came to an abrupt stop all that water came down on top of it.<<

Well, the trouble with that is that the liquid flows back to fill in the space befor any sort of cavity has any chance to be formed.

>>If the bow was planing at an angle then wouldn't any downblast come down on the collapsed decks at the tear explaning their crushed state?<<

Not unless somebody can point to some emperical testing to show that it does. (To my knowladge, nobody has!) Keep in mind that with
a) her own structural integrity severely compromised, and
b) the sections of the hull falling at between 25 to 30 mph, only to
c) all come to a very sudden stop on impact with the bottom,

you have a situation where Titanic's own mass was working against her. You don't need downblast to wreck what's left of her structure. Kinetic energy alone is enough to do the job.
 
Ryan McKeefery

Ryan McKeefery

Member
Obviously the force of her falling alone was enough to bury her nose, but in 60 feet of sediment?
That would need a large amount of inertia to bury her that far.
Regards, Ryan.
 
Michael H. Standart

Michael H. Standart

Member
>>Obviously the force of her falling alone was enough to bury her nose, but in 60 feet of sediment?
That would need a large amount of inertia to bury her that far.<<

Yes you would. But consider that over ten thousand tonnes of mass plunging through the water column at 25 to 30 mph backed up by the mass of the water within the hull has a lot of energy. You might also wish to consider that the sediment isn't really all that dense to begin with. it's not as far fetched as you think and the end result speaks for itself.
 
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Paul Wilkinson

Member
Ryan,

Let's use your own analogy. Bring your hand down to slap your thigh, stop and feel the draught. Now bring your hand down again and slap your thigh. Which hurts more? The force of Titanic hitting the bottom was way greater than any following down-flow of water. Michael is right.

Cheers

Paul
 
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George Huck

Member
What is the Down Draft theory and what is it trying to account for?
 
Michael H. Standart

Michael H. Standart

Member
>>What is the Down Draft theory and what is it trying to account for?<<

Down blast theory actually, and the premise as I understand it is that the hull decending through the water column would have drawn a current down on top of it, and thus account for at least some of the destruction. While I'm still skeptical of it...Dr. Pelligrino is no physicist...he may not be wrong about it if the evidence of other shipwrecks is any indication. He may well have the last laugh on this.

For all that we know about how a sinking ship behaves after submersion, there's a helluva lot more that we don't know.

As always, more research is needed.
 
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