What caused the damage to the stern?

[Alicia Coors]

The view of certain credentialed naval architects is that the stern section exploded after reaching a depth of about 300 feet. In their view, the compressed air inside the wreck violently forced its way out, splaying the sides asunder and rolling back the poop deck like a sardine can.

I think this is impossible, because the pressure inside would never exceed ambient. Does anyone know how these mature, educated engineers might explain it? Failing that, can anyone suggest how the stern got wrecked?

 

[Chris Mazzella]

Hey Alicia
There was alot of air trapped in the stern section and as the pressure increased it began compressing the hull til it literally exploded from its compressed air. Also i think it had a hard hit on the bottom which couldnt have helped.

 

[Chris Mazzella]

oops sorry i miss read some things sorry havent been feeling too well. sorry again

 

[Michael H. Standart]

>>I think this is impossible, because the pressure inside would never exceed ambient. <<

Okaaaaay....since this seems a valid question, perhaps somebody who can find something with the science to back up or refute these positions can do so.

 

[David G. Brown]

The commonly-accepted theory is that spaces such as the refrigerated storage rooms did not flood passively, but retained air. As the stern sank, the walls and decks which made up these enclosed spaces were forced to sustain the increasing water pressure. At some point (different for each large space) the theory is that they imploded (collapsed explosively inward). An underwater implosion can be quite violent, as was illustrated by the Thresher disaster.

A number of survivors in lifeboats reported hearing dull "booms" or sounds like large artillery at a distance after the stern disappeared. These sounds are attributed to the implosions.

There is controversy over whether the air inside the imploded spaces would have rushed out in a near explosive fashion. Or, some suggest it would have come out as compressed "bubbles" and only expanded as it floated upward outside the confines of the stern. One thing certain, air expelled from an implosion would have been compressed to a fraction of its sea level volume by the pressure of the deep.

Either way, it is probable that air trapped beneath the poop deck would have created buoyancy sufficient to have started pulling that deck upward. Water pressure from the descent probably finished the job of "peeling" that deck back like the lid of a sardine can.

All of this is speculation as it happened out of human sight. What we see are the results. The only firm conclusion is that sinking is not always a quiet event, but can be one full of violence for the ship involved.

--David G. Brown

 

[Samuel Halpern]

Upon collapse of an inclosed space, the air inside would have compressed to a fraction of its sea level volume and escaped as compressed bubbles. The violent compression of the air is what an implosion is all about. Think of it as an explosion run backward in time.

 

[Alex McLean]

David,
Can you tell me which passengers and crew heard these reports, and when they stated them (inquiry, personal reflections, etc.)
My best,

Alex

 

[Paul Lee]

I think Frank Prentice heard dull thuds below him as he lay in the bottom of the lifeboat that rescued him.

By the way, does anyone think that the stern "flipped over", so that it was heading fan-tail downwards before it imploded? I ask because the poop deck is peeled in a fore-aft way, not from the aft forewards.

Cheers

Paul

 

[Alicia Coors]

It is obvious to me that the stern imploded (as the phrase "the pressure inside would never exceed ambient" in my initial post intended to imply). The hull girder may have been weakened by the differential pressure, but most of the damage was internal.

My question is: what could possibly explain why people with an engineering background would posit the stern being wrecked by explosion? Roy Cullimore went so far as to suggest that the poop deck was peeled back by compressed air rushing out of the 3rd class stairwell. I not only don't see how that would happen, but I don't see why he would think it could.

The idea that the shell plating was detached by the slipstream also seems unlikely. If water pressure alone could account for ripping the plates loose, they would be spread all over the seabed. But they aren't. They're either hanging from the hull by a thread or lying next to it. The following explanation for this arrangement might fly:

Owing to the high concentration of mass in the engine spaces (compared to the bow section), the stern section dropped much faster under the influence of gravity than the bow, hitting the bottom at considerably higher velocity than the 22 knots that the model bow did. The damage shown in Roy Mengot's model of the stern at http://home.flash.net/~rfm/STERN/stern.html is totally consistent with a sudden stop from a high speed. As the incompressible water inside looked for an outlet under the influence of the collapse, it both blew the sides out and produced a jet through the stairwell that tore the poop deck loose and folded it back.

 

[Samuel Halpern]

quote:

My question is: what could possibly explain why people with an engineering background would posit the stern being wrecked by explosion? Roy Cullimore went so far as to suggest that the poop deck was peeled back by compressed air rushing out of the 3rd class stairwell. I not only don't see how that would happen, but I don't see why he would think it could.

You would have to ask them. I agree with you. There would be no explosions in the stern section. Your explanation may be the answer to the observed damage.​

 

[David G. Brown]

I have no problem accepting that the slipstream resulting from sinking could have "peeled" the poop deck back. In fact, that does appear to be what happened.

As to the air explosively coming up the third class stairway...well, i'm with Sam's view that the bubbles would be compressed and not expanding violently. They would, however, have gathered beneath the poop deck where they would have for a while provided buoyancy which may have helped lever the deck off.

As to who heard explosions, the answer is just about everyone who described the last moments remembered something that sounded like cannons or thuds. (Or, implosions?)

As to TV documentaries...what comes out on the screen may not be exactly what the contributors intended. The goal of entertainment TV is to attract sufficient number of viewers to "sell" to advertisers. Ads in American TV lingo are called "spots." During my days as a news producer we had a saying, "see spot run. Damned spot better run!" The term "run," of course meant that it got on the air as planned. The news was simply the stuff between spots.

So, keep in mind that anything on TV is first intended to entertain and draw an audience. If secondarily it enlightens, so much the better. But, truth and facts are not required in TV productions. I daresay there must be hundreds of "horror stories" about how scientific research was twisted by the documentary producers just to have a more exciting program.

-- David G. Brown

 

[Bill Wormstedt]

Alex - you can find some of the passenger & crew testimonies of what they saw and heard in my article here at ET - it's call "The Facts - What Did the Survivors See of the Breakup of the Titanic". I went thru all the testimony at both Inquiries, and excerpted what was said.

 

[Alicia Coors]

David,

I understand your remark about the trapped air providing a little buoyancy, but once that air was submerged by 99 feet, it would only occupy one-fourth of its sea level volume (assuming that everything that was going to implode had done so by then). That probably wouldn't provide enough buoyancy to lift very much.

But your slipstream analysis is probably spot on. If the hull was headed down fast enough to smash to bits on the bottom, there was undoubtedly enough flow across the well deck to peel up the poop.

I have no doubt that the witnesses were hearing things like the refrigerators imploding.

But I remain a little surprised that a marine engineer would suggest that the stern was wrecked by explosions (even for TV consumption).

 

[Jeremy Lee]

>>But I remain a little surprised that a marine engineer would suggest that the stern was wrecked by explosions (even for TV consumption)<<

Obviously! There is nothing in the stern that would cause an explosion, at that time he probably mixed up the words explosion with implosion.....

 

[David G. Brown]

A thought -- As the stern went down, air had to come out. Otherwise, it would have remained buoyant and might still be floating. That air was compressed by the sinking of the stern. How much? I don't know. However, motion pictures of ships sinking (mostly WW-II torpedo victims) that I have seen often have hatches blowing open and other signs of compressed air "exploding" outward. Could compressed air up the 3rd class stairway have damaged the poop deck? Maybe, or maybe not. But, the result would have been an increasing "blast" of air in that space.

As to what scientists say, they are human and sometimes toungle their tangs. I suggest that Alicia attempt to contact the people involved. I've had great success with polite e-mail inquiries.