Are there any folks out there with technical knowledge of the hydrodynamics that would come into play regarding the Titanic when she sank? Did the fact that she broke apart allow for the lack of suction? What were the differences between the suction near the stem and the suction near the rear of the ship as it descended?

Bill DeSena

Former Member
Hi Maureen,

While not exactly a true scientific experiment I tried this idea in my pool over the weekend with some interesting results (my wife thinks I'm crazy anyway).

I constructed a mockup in heavy weight tinfoil wrapped around a cardboard honeycomb piece of packing material that has several small compartments. I added a piece of dowel for the keel and tested the effects of suction as I pulled the thing below the surface of the pool by the keel without allowing it to fillup with water until it was pulled below the surface. To view any effects I dropped several handfuls of miniature plastic figures around the 'stern section' in the water. The thing took a surprising amount of force to pull under water and as the water forced itself into the honeycombed interior it burst through the 'hull' in several large rips. Meanwhile the little plastic people floating around the 'break' did get pulled under the water as the thing sunk or more properly was pulled below the surface they got pulled under too. The infesting part was the plastic people near the end of the stern just got bobbed around some and didn't sink when I did this little test.

Yes, I know. This wasn't anything like a hydrodynamic test done with proper controls and equipment and no scale was set either except that the plastic people were about the right scale to my model but the results were still interesting (and fun).

Maybe the survivors were accurate afterall when they said there was no suction from the stern as it went under. Perhaps the only real witnesses of suction who were in the water near the break faired the same fate as the plastic ones and were unavailable to testify to the event.

I think the stern really didn't sink in the true sense of filling up with water and settling lower in the water until submersion and therefore the 'suction' associated with sinking isn't the actual physics at work here. Since the stern was not water burdened and was literally pulled under by the sinking bow the water around it must have behaved differently. In my experiment when the force of water pushes into the hull and bursts through it that was when the plastic model people near the open end of the stern in the water go down beneath the surface. Interesting too was that while they would float undisturbed on the surface after being forced down a foot a\or so they tended to remain submerged while the figures not submerged floated away on the surface.

Regards from the pool:)
This is an interesting note, Bill. If this was how it worked, then that would tend to bear out the contention that the stern section wasn't completely seperated from the ship until it was completely submerged. It would be interesting to see if any marine engineers got the same results.

Michael H. Standart
I can just imagine the corps of army engineers, an aluminum foil covered ship model, little plastic men everywhere and Bill's shaved head...I mean, face shining into the lens while Mike Wallace puts this on Sixty Minutes in Bill's Pool.

Oh, I do apologize for the mistake...the corps of marine engineers.

Seriously though, I really think this would be a great thing to try. Any MArine engineers out there? Maureen.
In reading the Cullimore paper, I guess that I had seen where the discussion was one solid vessel versus broken in two pieces, but this article speak of three pieces and I have seen others that have stated the same thing. How would it breaking into three parts have changed the scenario, if any?

If your wife leaves you because of this Bill, I truly am sorry. This is interesting! Maureen.

Jason D. Tiller

Staff member
Hi Bill!

That's a very interesting experiment you did. Sounds like fun. Thank you for your information.

Best regards,

Jason D. Tiller

Dean Manning

Former Member
hi all.

Maureen, this is definitely an interesting question!

For what it's worth, I definitely think that the lack of suction was primarily a function of two things, the shape of Titanic's stern, and the rate at which the stern slipped below the surface.

Suction is caused when water, which has been displaced by an object(which, is what creates buoyancy forces on ship hulls, and allows them to float). When the object is removed, the water rushes in to fill the void. In the case of a sinking ship, as the ship moves away from the surface, the water rushes downward in attempt to fill the void. Also, it seems that, the faster the ship goes under, the more space it leaves open per unit time, which makes the filling in process more turbulent.

The rounded back of Titanic may have allowed the water to fill in the void much more smoothly. The best way to think about this is to take something square and flat that floats, and something round that floats. For instance, maybe something like the shape of a cd case and a coke can. If you take the cd shaped object and push it under water, the water fills in over it violently(violently is relative here...). However, it you take the coke can and lay it sideways(which represents a rounded surface) and pull it under, the water seems to fill in on top of it much less violently.

well, this is my theory. My $.02 cents worth. I'm now bracing myself for the onslaught... ;)

Dear Dean,
I do not think that I have ever "met" you before, but then I am new at all of this. I like your theory about the roundedness of the floating object. And I feel that your logical offering is worth way more than $.02 on the open market. At least $ least. (he he) Anyway, thank you for your kind comment about it being a good question. I had asked about it in another forum and i believe that one of the Mikes (if I am not mistaken) came up with the fact about the suction and advised finding out about the hydrodynamics. I advised that I would try to find someone at work that knows about this stuff, but I also thought that asking here would be great too...and it sounds like we have a lot of very knowledgeable people right here.

Thanks for adding some great thoughts Dean. And great "Meeting you". Maureen.
But wait....we now have a corps of engineers, an aluminum foil covered ship model, many tiny little men, a CD and a coke can in Bill's pool. Is Bob anywhere around...this may be a news first.

(Bill, I just want you to know that you are really special for going to all of that hard work for us. I really appreciate your heart to research this!) Thank your family for putting up with us too! Maureen.

Bill DeSena

Former Member
Hi all!

I did have the lovely company of several of my daughters girlfriends in the pool and aside from wondering if my model was something they could play with too and asking where the icebrg and lifeboats were, didn't seem to think I was too crazy, but cute!

I did observe that the stern didn't begin filling with water until about halfway under the surface and that was when the little poeple got sucked not only down but into the break and interior as well. Once the fantail slipped under the surface the stern was pretty well filled with water and the little swimmers just got splashed around a bit but not otherwise disturbed.

By the way, cameras at our pool when Indrani has her friends over would not be something to show on family TV!


Dean Manning

Former Member
Hi Maureen!

Thanks for the $1.95 appraisal! Nobody has, as of yet, put a price tag on me for my knowledge of mechanics. So, at this stage of my academic career, $1.95 is one heck of a bargain! I think I can buy about 6 packs of Reimen noddle soup with that much money! ;)

Anyhow, it's a pleasure to meet you. I look forward to reading your posts.

gotta run. later!

Bill, thanks for the update on the status of the sinking and suction. Okay, we'll call back the news cameras.

Any feedback on whether it would make a big difference regarding the third broekn piece? Also, I hear a lot about how it broke into TWO parts, what are the theories out there reagrding why or how it broke into three parts?

Dean, you are worth every penny! But I think you can get 6 packs of reimen and two six packs of red white and blue for that, I know this cause that is what the corps of engineers sent me to the store to get while they surveyed the pool, Bill and Bill's daughter's friends.

Dean Manning

Former Member
Hi all!

Maureen, you are a trip! What a witty reply!

Anyhow, about the two piece theory. In 1996, scientist thought that the Titanic broke vertically in two places, the first of the breaks being just aft of the third funnel. In 1998, the story changed, with the Titanic breaking vertically in one place. However, the 1998 theory does in fact leave the Titanic broken in three. Let me explain.

Titanic's stern is thought to have broken or split most of the way down to the keel and underbottom after the stern was pulled out of the water. After the spit, the stern settled down back in the water and then was thought to have been dragged down by the bow. It's thought that the keel and the double bottom of the ship actually held the bow and stern together until after the ship slipped under water. Once under water, the keel and underbottom gave way, leaving the bow and stern to make their own journeys to the bottom. Interestingly, scientist found what they think is the bottom piece laying on the ocean floor. Curiously, the piece is estimated to be about 90 feet long, with a big beam(ie: the keel) running the width of the piece. Also, the edges of the steel are stretched and torn, suggesting that the steel was slowly torn away (as opposed to being snapped) suggesting that it was tortured.

I hope this helps. If you have any questions about Titanic's break up, or decent to the bottom, I suggest checking out the links under "general titanic questions" called "how did the Titanic sink to the bottom?" and "Titanic breaks".

Thanks Dean for your confidence in me as a humorist. All those David Letterman's mother classes on humor paid off.

Meanwhile, I have to try t o imagine all that you wrote about the wreck and I also will read the references material in the closed threads part.

Thanks so much. Maureen.