The Downblast theory


Jul 9, 2000
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>>If the downblast theory is correct then why is the York Town which I believe is at 3 - 3 1/2 miles have no evidence of her island being deformed from a down blast water column.<<

It may have been strong enough to survive it, if there is any such phenomenon as downblast. I'm not wedded to anything one way or the other. All I did in my previous post on this matter is conceed that Dr. Pellegrino may be on to something.

>>Its hard to even consider what is possible and what should be thrown out the window.<<

Not neseccarily. Yes, amatures can make useful contributions and at one point or another, every scientist was an amature on some level, if only because s/he was probing new ground that was outside of anybody's experience. Somebody had to be the first to figure something out or discover and explain something new. However, when it gets to that, eventually, you need to have people with the training and experience to understand the ground and then you have to find some means of testing it.

That in the end is what seperates a scientific theory from a mere hypothosis. A scientific theory has been tested. A hypothosis has not been. And as the late Dr. Richard Phillips Feynman said "If it disagrees with experiment, it is wrong."
 
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Matt Pereira

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Michael, I fully understand you were stating that Dr. Pellegrino may be on to something. I feel the same way. I was simply stating that I have thought about other ship wrecks and I know you cant compare them cause theres differences from wreck to wreck but I thought it was alittle odd though. For all we know Dr. Pellegrino could be right.

True amatures make useful contributions, I was just saying if there was more wreck footage or pictures out there even if they werent high quaility aviable to the public we might notice something. Just like on Titanic Model website they have a section if I remember correctly that people have used orignal 1911-1912 pictures of Olympic and Titanic to learn new things such as a water fountain port and starboard on the aft wall of the aft well deck. Just like with the Cameron exploration under the forcastle deck where he made it to the spiral stair cases and how there was a water fountain there which was un known. These little things are things that are found out though exploration and or pictures of say the bridge that are out there and after 3000 or so people one comes along and spots something that everyone else has missed. It could be important or it could be something that doesnt help with her current state or decomposition or sinking.
 
Jul 9, 2000
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>>I was just saying if there was more wreck footage or pictures out there even if they werent high quaility aviable to the public we might notice something.<<

If you're talking about the raw footage, I'm not entirely sure about that. Most of it suffers in quality from the usual problems of trying to photograph something with the only available light being whatever you bring with you. A gifted amature may well spot something in the gloom, but most people out there would have no idea what they were looking at much less whether or not it was signifigant. That much takes the eye of somebody who has some actual training in this sort of thing.
 

Tom Barron

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Hi All

A factor in the difference between Yorktown and Titanic is that the Titanic had a break in her hull and the bow section has less resistance than the after portion of the ship. Yorktown went down in one piece and had that flight deck creating the area of maximum drag and went down keel first.

A useful rule of thumb in considering the downblast effects is that water has forty times what air does. You can generate useful amounts of electrical power with a one or two mile an hour stream. Multiply 25 or 30 mph times 40 and it will give you what the equivilant wind speed would be.

25mph in water equals one thousand miles an hour in air.

30 mph in water = 1,200 mph.

Now, how fast did the Yorktown sink? The Titanic was bow down, had SEVERE structural deformity happen at the break area, and the thing that holds up the interior decks on the ship are steel columns. None of the interior walls are structural and they were made out of wood.

If the break was straight up and down, (which it wasn't, obviously), it would be like riding in a pick up truck with your back up against the cab side. You're out of the wind. Ride next to the tailgate and your'e really getting a breeze. The ship stops in how many feet? All that water riding along in the 'burble' behind the ship is still moving. It's going to jam the water that is in the back of the ship a bit and those steel stanchions are bolted in place, but ... snap! All that interior deckage.. well.. that is one scenario.

With the ship breaking from the bottom up, those decks would be still together and pulled away from the hull plating and bent down right there at the surface.

The mast was big enough for men to climb up to the crows nest inside of it. Yet it's laying there against the bridge and to get it to break like that, it came down with a lot of force and broke against the superstructure. I'd say that the bridge disappeared on the way down to the bottom. The sides were open, the windows would not have held up to that much total pressure (a thousand miles an hour? Bye bye!) and away it went. Wouldn't be a bit suprised that the steering wheel went on the way down, too.

The down blast coming from aft and sweeping forward would have been shielded by the superstructure. If it did get around that obstacle, then it would have the well deck to cross and the cross section of the ship is getting less and less the further towards the bow you get. After flowing over the bow, the mud 'bow wave' would still be shielded from the water by the anchor handling deck over the forecastle.

Hope that force of water verses force of wind gives you a little more of a handle on just how much force was hitting the back end of the bow section.

Tom
 

Danger-Mouse

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Surely a downblast would be noticeable on the stern section of the wreck as well? The middle part of the stern section (corresponding to the bridge on the bow) is the 2nd-class boat deck entrance. Of course, the heavy damage to the stern section may disguise any evidence for said downblast, but the 2nd-class boat deck entrance ought to have been flattened. And yet, it is one of the highest points on the stern section.

Any thoughts?
 

TimTurner

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Dec 11, 2012
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Not sure if this is the answer, but here are three things to consider on your way to finding it:

(A) The stern section didn't sink like the bow section. It pinwheeled down, where the bow went down straight. The column of water behind the bow would have been a lot more coherent, and therefore stronger. The water column behind the stern would have been more turbulent and therefore weaker. Think of a mob of people wrestling with each other, verses a mob of people all pushing in one coherent direction. Same energy, but a greater effect when everyone is pushing together.

(B) I suppose it's not the center of the wreck which is important, but the center of the cross-sectional area perpendicular to the column of water following behind. The water following the bow would have focused on the aft section of the bow, then raced forward when the bow came to a stop. The water column on the stern would have probably hit off-center in the midships of the stern and brushed outwards and sideways.

(C) Lastly, the bridge was basically a wooden box set on top of the ship. The second class entrance is the top of a stairwell and rooted down enough to support the 2nd class elevator. So it probably has a stronger structural support than its counterpart structures on the bow.

I'm not sure about the downblast, but I lean in favor of it. Just wave your outspread hand through a swimming pool or bath tub and you can feel the effect. Imagine your hand is the size of an office building and moving at 40 miles an hour. The question I have is why wouldn't the downblast effect come into play? And how much force would such a wake have? When leaving harbor, the Titanic had enough wake to pull the New York from its mooring lines, yet the Titanic's top speed was about 25 miles per hour and it wasn't nearly doing that at the time. When it hit bottom, it was going 40 miles per hour. It's safe to say the Titanic was going more than twice the speed, which per k=mv^2 means it had at least twice the energy in it's wake.

---

Correct my math here, somebody who has better figures. Fill the volume of the bow with water at 62.38 pounds per cubic foot. Doing some quick geometry figuring the bow section as a wedge (stem to bridge) 170 feet long, 60 feet high, 45 feet wide (avg) and the rest of the bow section (bridge to break) as a box 90 feet wide by about 90 feet high, by about 200 feet long. That gives a volume of 2079000 cubic feet, that gives the water inside it a weight of almost 58000 long tons. At 40 miles per hour, the water displaced by the bow will be carrying 8.4 billion joules of energy when it hits the bottom, or the equivalent energy of two tons of TNT. That's a lot of force to write off.

Video of 1 ton of TNT: 1 TON bomb - YouTube
 

Jim Currie

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Water exerts pressure according to depth. In 'pure' salt water, it exerts a pressure of 64 pound per cubic foot of depth.

If Titanic's bow section sank on an even keel (which I think is rubbish) then the the pressure on top of her boat deck and all round it at a depth of say 1000 feet would be 1000 x 64 = 64,000 lbs/ cu. ft. or 28.6 long tons/ cubic foot.
Surely, for water to 'fall' into the space immediately above the deck as the deck decended, there has to be an area immediately above the deck where the water pressure was less than the weight of the water column above it? Is that posssible?
The ship is sandwiched between water at different pressures. The pressure on the keel would be almost 3 tons/cubic foot or 10% greater than the pressure at boat deck level. There would therefore be a braking effort. This effort would allow pressure at boat deck level to quickly equalize above the falling ship section. Thus no 'downblast'.

Just my ideas!

Ji,m C.
 

Cam Houseman

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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.
I like the theory, but how come the First Class entrance sign was still attached by the Grand Staircase? Kinda doesn't help the theory
 
Jul 9, 2000
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Why is there a glass vase sitting pristine and apparently undisturbed in it's holder within the wreck even though everything around it is a jumbled mess?

We don't know. Anomalies happen.

Butt so far the overall picture points to downblast being a reality.
 
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Cam Houseman

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I still see a lot of people disregarding the theory, and recently I've thought of a good analogy

When I walk home from School, a bus passes me. When that bus passes, a couple seconds later, I feel a blast of wind hit me, and ends after 1-2 seconds.

I think that is a good example of horizontal downblast, if you ask me. So why can't a 22,500 ton section of the ship (the Bow) experience the same? Water likes to follow things, you can see it if you swipe your hand through a water filled sink. The water has to be displaced as well, so imagine the trail of water following the Bow and Stern sections as they impacted.
 

Jim Currie

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Hello Cam.
Your bus is moving horizontally through a medium at equal atmospheric pressure.

On the other hand, a sinking object does so vertically through a medium of ever-increasing hydrostatic pressure.
It follows that when the sinking object displaces water, a volume of water of equal pressure will rush in from above and the sides to fill the void of displacement.
However, since the water pressure below the void of displacement is always greater than the water filling the void of displace ment, - there will be no down blast - just a horizontal and vertical equalisation of pressure according to depth.
The proponents of down-blast forgot about your bus-like 360-degree horizontal in-fill and equalisation of pressure
 
Jul 9, 2000
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A number of years ago, I was skeptical of the downblast theory. I have since changed my opinion to one of accepting it, but with the usual caveat of pointing out that more research is needed.

It may hold up....or not.
 
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Jim Currie

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A number of years ago, I was skeptical of the downblast theory. I have since changed my opinion to one of accepting it, but with the usual caveat of pointing out that more research is needed.

It may hold up....or not.
As I see it, Michael, the sinking hull sections were open to the sea, consequently, there was constant equalisation of pressure as these sections descended to the bottom. "Downblast" is simply an expression that means equalisation of the pressure of the medium... in this case water. If the water pressure is constantly equalising, then there is a minimal disturbance of the surrounding sea.
 

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