Need someone to hold my hand for my project


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Paul Lee

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Hi all,
As some of you know, I'm working on an interactive sinking Titanic animation for my webpage. I have got the GUI sorted out, although I feel that it needs more work, and I have some algorithms in place that calculate the amount of water in each compartments based on its geometry and hydrostatic equations.

What I need help with is working out how the Titanic's centre of mass shifts as water enters the damaged compartments, and also how the forward list can be calculated. Basically, I'm attempting to recreate in a very simple way the work of Bedford and Hackett and Wilding but in a much simpler way.

If anyone technically minded people want to help guide me thorugh these points, please do let me know!

Best wishes

Paul
 
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Paul Lee

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Note: I am posting this to the board because David Brown's email is not working, so hopefully he'll see this!


Hi David,
Yes, it was a bit disappointing. What I am really after is someone to help
with nautical
formulae etc. to duplicate those animations as seen in Cameron's film,
Discovery channel
shows etc. I've found lots of sits that discuss the list of ships, but not
the trim, which is what
I'm after...and all this stuff about metacentre etc. just go over my head
(its been years since
I did physics!)

Thanks for telling me about your own research, although I thought that
Barrett stated that
Boiler room 6 was opened to the sea when the side of the Titanic opened up
about 2 feet
about the floor plates? You're right about no witnesses saying at the
enquiries that water
flowed over the top of the bulkheads, but I do remember someone (whose name
I can't recall
right now) saying in ANTR that he was surprised to see water flowing down a
staircase
and assumed that the water must be coming down from the next foreward
compartment....?

Anyway, keep up the good work, and hopefully you'll share some more of your
findings
soon!

Take care

Paul
 
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Erik Wood

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David is in the process of changing ships I hear from him on occasion. If you need something I would be more then happy to assist.
 
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Paul Lee

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Aha! I have had some little success in my project. Whilst at home for Christmas I looked through my Encyclopedia Britannica volumes and found an equation that links various parameters such as length between perpendiculars, loaded weight etc. to the trim of a ship.

The only problem is that the trim angle only works if the angle is "small" (I guess they're using the small angle approximation where tan theta = sin theta = theta).... is there a more general expression out there?

Many thanks!

Paul
 
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Paul Lee

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Whilst on the 'net, I thought I would drop by the Harland and Wolff website as I know that c.1994/5, they were selling copies of Edward Wilding's notebook for the 1912 BoT inquiry, and I hoped that H&W also had copies of Bedford and Hackett's notebooks....what a vain hope! There doesn't seem to be anything to buy from H&W now....
sad.gif
 
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Paul Lee

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It seems that this little project has been temporarily abandoned - I had forgotten the extra flow rate into the hull caused by the movement after the collision (only the excellent "Last Log of the Titanic" deals with this, I don't think Bedford and Hackett, or even Wilding in 1912 included this). This will complicate matters, oh dear!
sad.gif


Best wishes
Paul

 
A

Alicia Coors

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Paul,

Sam Halpern ran the equations on this in early January, and concluded that the ram effect is negligible. First, the pressure isn't much even head-on; furthermore, Titanic's openings were almost perpendicular to the flow.

I say ignore it, and carry on.
 
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Paul Lee

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Just a quick note to say I've done some recomputation of this. For the first four compartments, I've estimated the tapering of the bow to be an angle of 12 degrees. The water entering the hull (pependicular to the hull) would be a factor of sine 12.
For half speed, I estimate 10 knots; 17 feet per seconds, or 5.1 metres per second. So, the water flow would be 5.1 sin 12 = 1.1 metres per second.

The continuity equation would be density*area*velocity = mass rate. The area I obtained from the B&H report, to be 8.6 square feet, or 0.78 square metres. So, this yields 858 kg per second, or 0.858 cubic metres per second.

Over the 10 minutes that the ship was alledged to have cruised at half speed, this would yield nearly 515,000 kg or nearly 515 cubic metres (18600 cubic feet).
The calculations of B&H seem to be flawed, but they do give an indication of the amount of water in the hull by the time the ship stopped steaming - perhaps by condition C2 (12.00pm), which would be nearly 8,000,000 kg (8000 cubic metres). So, yes, the amount of water caued by the ram effect would be small in comparison, and it would be spread over, in this case 4 compartmens (I only did the first 4 as boiler rooms 5 and 6 seem to be more parallel to the flow of water).

So, for each compartment, neglecting the coefficient of discharge (B&H values from tables
6A-7B)
:
fore peak; damaged area = 0.6 square feet.
Water entering hull by Ram Effect=
area (0.06 sq m)
v = 1.1 metres
density = 1000 kg m^-3
Therefore mass rate = 66 kg per second
B&H mass rate = 317 kg per second

hold 1 - as before, but with an ingress area
of 1.5 square feet, or 0.32 square metres,
mass rate = 352 kg per second
B&H = 375 kg per second

hold 2:
mass rate (ram effect for 3.1 square feet/0.14 square metres) = 154 kg per second
B&H = 900 kg per second

hold 3
mass rate for 3.3 square feet (0.3 sq metres)
= 330 kg per second
B&H = 2180 kg per second

Hmmm. The values for hold 1 look a bit dodgy. I'll have another look tomorrow.

YMMV.
 
Samuel Halpern

Samuel Halpern

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If you re-work this you may want to consider what Capt. Smith had to say about speed, revolutions, and telegraph orders on Olympic:

“Full speed about 20, about 75 revolutions, and half speed 50 would be about 15, slow 30 would be 8 to 9 knots.”

No mention about dead slow, but I would guess about 4-5 knots at 15 rpm. Despite Olliver's statement about seeing 1/2 speed rung on telegraph, the half-speed position was nearly an angle of 90 deg forward on the telegraph handles. Slow speed is what he may have seen from the handle position but assumed it was half. The telegraphs were unlighted, so it was handle positions that were seen. Also, if you believe Scott, he saw ahead slow rung down in the engine room. And Dillon said he saw the engines go ahead slow for a short time but he probably had no idea just looking at the engines between half, slow, or dead slow. Anyway, the length of time that the ship went ahead is really unknown and debatable, and that parameter is the major uncertainty here.
 
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