Did Funnels Flatten upon Collapsing?

[Kyle Naber]

If the popular theory that the first funnel collapsed due to the water pressure on the outside of the structure, would it be probable that the cylindrical figures would pancake in on themselves as they fell?

 

[Roger Southern]

I think it would be quite likely. If you look at the photos of a funnel being moved out of the assembly shed it has (probably) wooden formers inside to maintain it's shape whilst on it's side. They weren't designed to lie flat, only to stand on end, obviously. But that's just my opinion as I have no engineering calculations to back it up.

 

[Kyle Naber]

If not the first and second, the two aft funnels would have experienced some sort of damage as they slammed onto the boat deck.

 

[Miller88]

Anyone know the general construction of the funnels? As in how thick was the steel that made them up? Were there any supporting structures inside other then steam vents and piping etc? It seems difficult to predict how the funnels would have reacted to the impact of the water surface without knowing the construction of them. As pure hollow tubes then I would also agree that they may have collapsed in on themselves to some degree.

 

[Kyle Naber]

I believe they were pretty fragile. I think they were constructed with 0.5 inch thick plates and were relatively hollow inside.

 

[Miller88]

If only a half inch then I would assume that they would have flattened, at least the top most portions anyway

 

[PRR5406]

Likely they lost shape, but since they filled with water on the surface, there'd be no implosion as they sank. I doubt they completely flattened, Half inch steel is pretty rugged stuff. Also, the mechanical force (distance versus time) made the top impact with the greatest force.

 

[Bill Vanek]

Regardless of how egg-shaped their cross-sections became due to impact when falling over, once the stacks got in the ocean and started gaining speed downward, water friction on their surfaces would have a large effect. The effect would be to turn the stack vertically, which would make it have the least friction and therefore the least unbalanced forces on it. That is, any unbalanced force at first would push the stack, and not until the alignment resulted in the fewest unbalanced forces would it stop realigning. That's how a falling object gets aligned into its most efficient, least unbalanced orientation as it falls. In this case, each stack would soon become oriented straight up and down (either right-side up or upside down), and would then gain speed like a bullet. Due to asymmetry in construction or due to deformation during the mayhem topside, the path of each 'bullet' might vary slightly, causing a tight spiral path down. The speed would be high for so much weight presenting such a small cross-section of metal in the direction of travel. I imagine that each funnel would have buried itself in the ocean bottom when it impacted, cutting in like a cookie cutter through dough. I'd bet that for a time after impact, each stack left a ring-, donut-, or disc-shaped color change or pattern in the sediment. It's extremely likely that currents have obliterated such evidence, so it would take metal detectors to find the stacks--which by now are huge cylinders of iron oxide (rust) instead of steel--but that's still magnetic.

 

[Kyle Naber]

Regardless of how egg-shaped their cross-sections became due to impact when falling over, once the stacks got in the ocean and started gaining speed downward, water friction on their surfaces would have a large effect. The effect would be to turn the stack vertically, which would make it have the least friction and therefore the least unbalanced forces on it. That is, any unbalanced force at first would push the stack, and not until the alignment resulted in the fewest unbalanced forces would it stop realigning. That's how a falling object gets aligned into its most efficient, least unbalanced orientation as it falls. In this case, each stack would soon become oriented straight up and down (either right-side up or upside down), and would then gain speed like a bullet. Due to asymmetry in construction or due to deformation during the mayhem topside, the path of each 'bullet' might vary slightly, causing a tight spiral path down. The speed would be high for so much weight presenting such a small cross-section of metal in the direction of travel. I imagine that each funnel would have buried itself in the ocean bottom when it impacted, cutting in like a cookie cutter through dough. I'd bet that for a time after impact, each stack left a ring-, donut-, or disc-shaped color change or pattern in the sediment. It's extremely likely that currents have obliterated such evidence, so it would take metal detectors to find the stacks--which by now are huge cylinders of iron oxide (rust) instead of steel--but that's still magnetic.

I think the funnels would have been crushed inwards like a soda can on their way down. If it’s true that water pressure and simple turbulence compromised the integrity of the structure and caused it to collapse, I don’t think it would have had much strength on the way down.

 

[Seumas]

Didn't one of the expeditions to the wreck claim to have found partial remains of the funnels a number of years ago ?

 

[Bill Vanek]

"I think the funnels would have been crushed inwards like a soda can on their way down. If it’s true that water pressure and simple turbulence compromised the integrity of the structure and caused it to collapse, I don’t think it would have had much strength on the way down."

Are you saying that the funnels had air trapped/contained in them somehow? That would be the only way for them to get crushed. If they were just open tubes, with no way of holding air, there would be water flowing through and around them as they sank, and no crushing.

 

[Kyle Naber]

That’s very true. Would it then be possible for the base of the number one funnel to be crushed as previously hypothesized if the top of the funnel is open?

 

[Bill Vanek]

I'm not sure what you mean by "the base crushed as previously hypothesized". Are you talking about some theorizing from 1912 or 1986, or are you referring to the first responses at the top of this 'funnel flattening' forum page?

I don't know anything from yesteryear about the funnels. But as a mechanical engineer who has worked on pressure vessels, tanks, piping, a submarine, welding, and much more, I can say that a funnel could definitely get damaged when it tipped over on the Titanic. But "damaged" would be considerably less than "crushed" or "flattened". The most expected damage would be a dent from the funnel falling upon some sort of small/sharp thing like a stout railing or the edge of a boathouse. A second expectation would be localized buckling inward near the bottom on the "downhill side" (the side that it is falling toward) due to the way it was breaking loose from its mounts. And I might expect a little bit of "egging" (getting egg-shaped in its cross-section) if it really slammed down hard. Finally, there could be damage not related to the funnel's falling, but rather from a deck failure nearby, causing pulling on one portion of the funnel's mounting such that most of the funnel stayed mounted, but a piece tore out as a deck pulled away. (That last failure mode was what I always assumed had happened when I read that in the debris field was found "a portion of a funnel".)

Regardless of how many dents, tears, kinks, or egging could occur as a funnel came loose, fell down, and fell off the ship, if it is a long steel cylinder that is open on each end, with no double walls containing any trapped air volume, I'm 98% sure that my previous comments describe what would happen in the ocean. A cylinder would soon turn vertically and go speedily down. It would not tumble, crush, or flatten. It could wobble some, and would almost certainly spiral (due to asymmetry) rather than follow a straight vertical path. I wish that I had access to a swimming pool so that I could use some of my left-over sheet metal to make a cylinder and run tests to verify what I've said, though!

 

[Kyle Naber]

I was referencing theories that described how the first funnel may have fallen in the first place. Lightoller described the expansion joint opening while now there’s talk of the base buckling under the water pressure and it topped over.

 

[Bill Vanek]

Ah; I'm unfamiliar with that theorizing. However, the expansion joints being pulled open could not cause a funnel to tip over, because the expansion joints didn't run right at a funnel. There is a relationship, though: the stresses that were bending the ship and pulling the expansion joints open could have easily torn loose some of the cable stays that were holding the funnels. Each such indication was a separate symptom of major stress; one did not cause the other. And shallow water would have no water pressure on the funnels--certainly not enough to push them over by surrounding their bases. Water pressure increases by 10 psi every 23 feet of depth. So if we pretend that the port list of the ship caused the bottom port side of each funnel to sit 12 feet lower in the water than the bottom of its starboard side, it would result in just a 5-psi differential pressure on the elliptically shaped mounting of the funnel...and the pressure would be higher on the most submerged side! So, people's interpretations and guesses are attempts to explain things, but guesses don't usually hold up to physics.

There were no waves that night, so waves didn't topple funnels. Water pressure couldn't do it. The expansion joints wouldn't do it. It had to be the simple explanation of the ship listing hard to port as it was going down, and stresses causing cable stays to break somehow, allowing the funnel to finally drop. I recently heard of a man who bought property having a tall TV tower on it, held--as you've probably seen--via cables in 3 directions. He thought that he'd be smart and climb up and cut one cable loose so that he could then go down and tip the tower over. Well, once you release one cable, the tower goes over immediately toward the other cables, because cables work in tension only. The man paid for his lack of understanding with his own life. Now, if the Titanic had been steaming on a normal ocean surface, any or all of those cable stays could have been disconnected, and the funnels would likely have stayed in place, held by their mountings around their bases. Cables were there in case of high winds or pitching seas.