"Official" Version of Battle?

Discussions about the history of the ship, technical details, etc.

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Randy Stone
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Sorry George, since you made the assertion...

Post by Randy Stone » Wed Feb 23, 2005 3:46 am

...go buy that computer I told you about and justify your statement that his estimate is 'displeasing.'

:think: It's your complaint, so assume some responsibility and run with it. And if you're really industrious you can throw in all that minutia you claim affects the calculation.

Or you can just dodge the issue yet again, your call.

Randy, yawning over a lazy and truculent student :wink:

George Elder
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Silly boy...

Post by George Elder » Wed Feb 23, 2005 6:05 am

Randy, if you can't define viable, can't use your real name, don't share information freely, etc., how can you teach anyone? :negative: Heck, you couldn't teach a dog to pee. :lol: And after offering to dazzle us, you run for cover. So we'll take the subject up with Dr. F, who specializes in fluid dynamics. He will set aside some time to speak with me. I sent him the claims, methods, etc., and Foeth et al. will be able to determine the exactly what Dr. F says -- because he is the real deal, an experts expert.

George
Last edited by George Elder on Wed Feb 23, 2005 10:29 am, edited 1 time in total.

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Post by iankw » Wed Feb 23, 2005 8:34 am

You two are going to get this thread locked as well, if you carry on. I'm not saying it isn't mildly amusing to watch, because it is, but it doesn't help in the final analysis.

Hope you don't mind a newbie joining in?

Take care

George Elder
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Good advice.

Post by George Elder » Wed Feb 23, 2005 10:26 am

Welcome aboard! I sure hope this thread doesn't get locked up. I'm going to speak with a fellow who can clear up a lot of this mess, and I was lucky he would even talk with me given his work demands. But Dr. F is very intimidating. I can barely understand him on my best days, and he does not suffer ignorance lightly. Well, nothing ventured -- nothing gained.

George

Randy Stone
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George, the core issue here...

Post by Randy Stone » Wed Feb 23, 2005 11:03 pm

...has been resolved, your continued, undefined and unjustified 'displeasure' (Sun Feb 20, 2005 7:17 am) notwithstanding.

Your failure to understand that the current is not a meaningful factor, as demonstrated by Antonio and myself, is proven by your predictable insistance on holding your breath until you’re blue in the face in the light of the evidence.

You’re wrong, you know it and you know I know it.

However, when you want to quit sulking and come out to play with real facts, I’ll be happy to help you.

But let’s hope Dr. F. will be sooner heard from than Dr. Friedman on the weak cruiser bow syndrome...you dropped that one like a hot potato as well; let’s hope things work out differently here, not that we need an answer – it’s already there. But I won’t be holding my breath, as Iankw will witness, this is a typical tactic in disengaging from the field...that parachute, if you will.

Antonio’s estimate of 30 knots is pretty darned good and I would assign it a +/- 0.5 knot tolerance; it doesn’t get much better than that, my friend. And it doesn’t alter Antonio’s calculation to any meaningful degree...which is pretty much what I’ve been saying all along.

Randy, ever the hopeful -- even with the self conscious student. :cool:


Iankw:

No, I don’t mind one bit: newbies we’ve all been.

I am amused as well watching all the contortions George is going through avoiding the obvious. I do these calculations for a living so that’s why Antonio’s numbers made sense just looking at them and his methodology; when I ran the numbers on the computer I derived the tolerance stackup of 0.5 knots either side of the mean for the courses Bismarck was steering. George just has a hard time with my sharing of knowledge with him...especially when it doesn’t agree with his orthodoxies.

But watching George engage in those exaggerated contortions did have the benefit of prompting the wife and I into picking up some fine Dungeness Crab for dinner, very tasty. :lol:

Randy

George Elder
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An Empty Drum...

Post by George Elder » Wed Feb 23, 2005 11:30 pm

As usual Randy:

Lots of noise, zero substance, probably from too many head blows... :stubborn: And I certainly have sympathy for your poor wife. Gosh, enduring a dinner with you must be akin to having a root cannel with no pain killers. In any event, Foeth is now going over my notes, and he'll help make sense of them. I'll then dump the whole lot here, including what Foeth has to say -- and perhaps Bill C if I can contact him. It seems modeling current and wind effects is not as simple as some simple folks would have it -- but we'll let the notes and comments speak for themselves.
It has been a difficult day, and seeking to understand a specialist in fluid dynamics is no easy task. As noted, he limited the variables to just current and wind effects, and went running from there. And when he began moving into finite element modeling -- I simply shut down. Happily, Foeth will help us out. As for the claim current doesn't matter -- we'll let those words be judged accordingly.
With regard to offering information or contacting sources, who was it that claimed to have the So. Dak. study but failed to share it with John A., Phil, and a lot of other folks? Now, why would such information be witheld, or was it all a lie? Friedman never responded to me, so there is nothing to report. Seems simple enough, but you are welcome to give it a try.

George

George Elder
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Antonio: Please contact me off line.

Post by George Elder » Thu Feb 24, 2005 1:05 am

Hi Antonio:

Please drop me a line at ghe101@aol.com. I have learned a few things that may be of some help.

George

++++++++++++++++++++++++++++++++++++++++++++
Hi Jose:

I sent the relevant claims/positions regarding calculating the Bismarck’s speed via the shell splash method to a fluid dynamics specialist. We spoke for about 35 minutes yesterday, and it was a miserable ordeal. Dr. F reduced the variables to just current and wind speed for simplicity’s sake. He explained things as follows, and I must caution that I may not have gotten this all correct given his rate of speech, accent, and obvious annoyance. Foeth is going to help me understand the details, and I have already sent his the notes. But this is going into very heavy areas that are way over my head. I will send you what he says, and perhaps also get the inputs of four other specialists I know -- if I can persuade them to help us. This is not a simple subject, but we may be able to create a model that will help make an accurate speed determination if I can come up with some needed data. Here are my notes, such as they are:

+++++++++++++++++++++++++++++++++++++++++++++++

Must define terms first.

Dr. F: Denote the ship’s heading as X degrees and initial position as P1 along X, Y, Z coordinates. Then denote the ship’s mass as M (density x volume), wetted surface area as W, and above-water surface area as S. Also define hull depth as D and height above the waterline as H. This will allow us to begin determining the influence of current and wind on the ship relative to the influence of the current and wind on the shell splash's water column. What about length? Deal with L and B later.

I note these variables can be known in the case of the Bismarck. It seems ship height, depth, wetted surface area, and above water surface area matter a lot when measuring current & wind effects on relative course headings. “Anyone knows that,” he says. I think this is why Z axis is included. Needed for height and depth effect calculations, but don’t know for sure.

Dr. F: Denote a current direction of Q degrees referenced to X, Y, Z coordinates, and designate the velocity as V1.

Reply that the current's direction and velocity are not known. He insists that knowing these variables is an essential element in solving the problem. I reply some maintain the current and wind have an equal effect on both the water column and the ship and thus cancel out. He said I cannot claim this without knowing the relative characteristics of the water column vs those of the ship, nor the relative influence of the wind and current on each object.

Gives example: A large tanker when full vs same tanker when empty. When full, ship mass increases, wetted surface area W increases, and above-water surface area S decreases. Hull depth D increases and height above the waterline H goes down. Net result is wind influence on course decreases; current effect on hull also changes. In this case, must also factor friction differences due to greater mass and underwater hull area. Goes into depth-related friction coefficients. I am totally lost.

He asks what kind of current it was. I don’t know. He notes there are different types of currents and these can matter a great deal. Some vary with depth. Need help here.

Dr. F: Designate a wind direction of R degrees referenced to X, Y, Z coordinates and a velocity of V2.

Asks if the surface wind speed is known. I presume data we have is surface speed. He said winds can vary somewhat above the surface, and this is one reason ship height can matter. Very minor difference here unless vessel is very high relative to depth. On and on he goes about relationship of height and depth as it is influenced by wind.

Watercolumn.

Dr. F: Assume a water column that originates at point P2 referenced to X, Y, Z coordinates. Designate the water column mass as M2, wetted surface area as W2, and above-water surface area as S2. Also define water column depth as D2 and height above the water surface as H2. Notes dynamic elements. Don’t understand any of this. Many rapid questions.

“What is the mass of the water column?” Don’t know, varies with time.
“What is the area of the water column?” Don’t know, varies with time.
“How tall is it?" Varies with time.
"How wide is it?" Varies with time.
"What duration is column aloft?” Roughly 5 seconds. Just guessing.

Dr F says these data are needed to calculate the wind effects on the water column. He notes wind effects can be very large if the density of one object vs another is relatively low, the surface are is large, and the height is great. The object acts like a sail. Many more questions:

“Does the water column extend below the surface?” At some points.
“Has some or the entire column been ejected?” I think some.

Sounds disgusted. Notes that we must know these things if we are to calculate the current's effects on the water column.

Says the water column is not a craft. But it must be treated as such if we are to predict its position changes relative to the ship. The relative position changes of the ship and water column must be known if an accurate speed calculation for ship is to be made. Without knowing the column’s mass, wind-exposed surface area, underwater area and depth, etc., it is impossible to accurately calculate the effect of currents and wind on the relative position of the water column vs that of the ship. On to rate effects. Water column is in flux, M, H, etc., change. Difficult to model*. May be impossible.

I say the effects of wind and current are small, insignificant.

Doubts anyone with a serious understanding of fluid dynamics would ever claim this. [note: said in context of requiring the data needed to back claim of small/insignificant effect.]

Says we cannot possibly solve these kinds of problems if the needed data are not provided. All we will get is noise. Not science.

There are established formulae for calculating the conjoint influence of currents and winds on craft or objects with distinct characteristics. Available in seamanship texts. He does not see evidence that I show any understand any of this material.

Advises basic fluid dynamics text and study seamanship texts. Without data, formulae will not work.

Ducks are not lined up.

+++++++++++++++++++++++++++++++++++++++++++++++

* : I have been advised that a possible solution to the water column problem involves finite element analysis, but this is way beyound me -- and I am not about to get into computational fluid dynamics. I strongly suggest that anyone who wants to solve this problem has to be working in this field. Foeth does not think this will get us far.
Last edited by George Elder on Thu Feb 24, 2005 11:00 am, edited 3 times in total.

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foeth
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Post by foeth » Thu Feb 24, 2005 9:17 am

As far as current is concerned: if the current does not change much in the time span and area Bismarck is sailing, it is not important, as all things will move relative to each other. Ship sheep is measured both over land (absolute) and in water (relative). Note that the speed of a current compared the speed of a shell can be neglected for sure. Wind speed is a smaller component, and not dominating in the problem, but can provide enough force for the ship to steer at an angle: ships can have some drift angle (angle between actual path and ships longitudinal axis). I do not agree they cancel out however.

I assume the water column is the result of an underwater detonation, as I can't possibly see the entry in the water causing a major splash. I suppose you know the principle, it works the same for torpedo explosions and cavitation bubbles: the initial explosiong causes a shock wave which may cause damage (better not be in the water at that time ;) ). This is not what does the damage. The gasses of the explosion expand, but will quickly be overtaken by the force of the water. Normally the bubble would collapse again from all sides, but as it cannot entrain water when a surface is near, the collapse is assymetrical. The funny thing is that the vapor surface near the free surface will accelerate like an idiot causing a jet. I believe this is the jet of the water column, the jet that destroyes water tight compartments and destroys propellers by cavition (A bubble of 2 mm (tenth of an inch) has en estimated jet speed of 100-200 m/s (300/600 ft/s).

Apparently somebody though it would be a good idea to calculate it using FEM (Finite Elements Modeling), but why? What needs to be calculated exactly? The influence of wind speed on a heavy column? What you mainly see (especially at a distance) is spray and vapor being blown away by the wind. You need to predict the bubble collapse correctly, which is difficult, and THEN the influence of wind speed on that column as well. I can pretty much guarentee you that estimating the spray wil be difficult.

I'd start by ignoring both wind speed and currents. I think you don't need fluid dynamics but uncertainty analysis. What is the error in your estimated speed is you miss the position of the watercolumn by 10%? What is your error if the course deviates a few degrees? How certain are you of the time between recordings, and how much would an error of a second influence the results? Once you redo these calculations and more less estimate the error of all these parameters, you'll see that some factors will introduce a greater error than others. Oh, and you need to add them all up ( sqrt(error1^2 + error2^2 + ... +errorn^2) ). I do some scientific work from time to time and claiming to be accurate to within 3% is with an exercise as this is very unlikely. I'd start thinking about those questions before introducing FEM!

Once you do calculate the error, note that you can both add it an subtract it to your estimate. If you multiply this error by 2, you more or less have an interval of which you can be 95% certain what the velocity is, assuming you've made a good job at estimating all errors. I assume you'll get a speed like 28 kts +/- 5 kts

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foeth
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Post by foeth » Thu Feb 24, 2005 9:40 am

Example:

Speed = Distance / Time

The error in the final answer is the error of one component times the derivative in that component (called the sensitivity)

Error due to Distance:

E_dis = (d Speed / d Distance) * Error in Distance / Estimated Speed
= Error in Distance / ( Estimated Speed * Time)

Error due to time

E_time = (d Speed / d Time) * Error in Time / Estimated Speed
= - Distance / Time^2 * Error in Time / Estimated Speed
= - 1 / Time * Error in Time

Numbers from Antonio
Speed = 30 kts
Time = 16 secs
Error in TIme = 0,5s
Distance = 246,6 m
Error in Distance = 12,5 m

I introduce a 0,5 s error. I cannot assume that the speed on the camera runs true or that the number is read accurately enough, the point in time of the watercolumn is correct etc. The error in distance is about 5%.

With these numbers you get an error of
E_dis = 5,07 %
E_time = 3,12 %

Totals (5,07%^2 + 3.12%^2) ^ .5 ~= 6%

With basic numbers you get an error of about 6%. As I mentioned, to be in a reasonable error range, you need to multiply this with a coverage factor of about 2, so the error is about 12%. It's just a back on the envelope calculation.

The speed can be given as 30 kts +/- 3,6 kts. ANY speed in this range is CORRECT. Even if your estimate in time is perfect and the error in position is only 5m (2%) you're off by 1.2 knots.

George Elder
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And this is the problem.

Post by George Elder » Thu Feb 24, 2005 10:32 am

Hi Foeth:

This considerable error margin is the same sense that I was getting. And it does appear that there is enough noise, as Dr. F calls it, to result in an error margin that makes either Antonio or Rob's scenerio possible. I am not at all sure that anything can be done to refine the analysis given the shell-splash methodology being used, but your calculations show where a lot of the error might stem from that goes beyound currents, wind, etc.. Perhaps we should have been considering these elements all along instead of getting lost in bubbles. And it seems that even under the best circumstances, we'll still have an error margin that makes both Antonio and Rob's scenerios possible using the splash marker. In the end, I suspect we will have a few folks making subjective judgements about how to make the measurements more precise, and then they'll make them fit their favorite scenerio. You know how that goes.
I will still complete the exercise by enlisting the help of 4 or 5 additional fluid dynamics and oceanograpghy specialists. This may help us glean insights into a few other areas of concern we may not have addressed, and these may lead to methodologies that may better help to determine the Bismarck's speed. Yet, I must agree with your general conclusion that we will be lucky to ever get a very small error margin using the current methodology. Still, Antonio made an inventive effort, and I thank him for that. Well, much has been learned, but the problem remains.
Thank you for helping us, my friend, and for forwarding our research. I truely wish we could determine the Bismarck's speed with greater accuracy, but I am at a complete loss as to finding a means of doing so. Any ideas would be welcome.

George

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Antonio Bonomi
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Bismarck speed

Post by Antonio Bonomi » Thu Feb 24, 2005 1:24 pm

Ciao George, Randy, Ian, Foeth and all,

well I am glad to see that my Bismarck speed calculation exercise was of interests for you guys.

If we concentrate and leverage on everybody skill and knowledge that we can really move things forward :D .

I will not comment on the error margin or tolerances theory that can be all correct as far as I am concerned ( I like Foeth exercise and example :D ).

I will limit myself only to 2 very easy considerations that everybody can evaluate himself too :

1) Bismarck speed was of course very evidently far superior to Prinz Eugen ( that during the battle was sailing at 27 knots permanently ) and this is very obvious just by simply watching the photos and film referencing Nh 69722 as the starting point.
So 30+ knots ( Bismarck top speed ) is highly probable.

2) If Nh 69722 is showing Bismarck at 2000 meters than after 10 minutes ( at 06.04 ) Bismarck can be only at 1000 meters still on Prinz Eugen back, of course this assuming Bismarck '' flying '' at 30+ knots ( her top speed as said ) as seems probable from my measurements.
Bismarck cannot be at same Prinz Eugen level at 06.04 because this will require Bismarck sailing at 33 knots and she was not able to do that, so it is impossible for Mr Winklareth to sustain his theory.

Addittionally, Bismarck at 2500 or 3000 meters on Nh 69722 of course complicates the situation for Mr. Winklareth and is even '' more '' impossible than the already impossible evidence,.. pardon the joke of words :D .

So George, it is NOT Bismarck speed the problem that makes Bob theory out of any possible consideration once again, it is the starting distance of Bismarck on Prinz Eugen back at 05.55 showed by Nh 69722, that is a ''killer fact '' for him, and it is there for eveybody to see and accept as evidence and a matter of fact.

But it is a problem for him ONLY because differently, on my re-construction of the events Bismarck is at around 1000 meters back to Prinz Eugen at 06.04 and on her starboard side and as you can see is very possible and highly probable looking at what we have so far.

This is the current status and as you can see there is an enourmous difference between the 2 situations, .... 1000+ meters than cannot be filled in with imagination nor inventions, .. Nh 69722 is there, the ship speed are there too,.. my work is fine and Mr Winklareth one is impossible, .. those are the irrefutable facts currently.

I think is a very easy and elementary fact under the eyes of everybody to be realized.

Now we can evaluate a delta ( tolerances ) on speed ( slowing down Bismarck from her top speed ) or a delta on Nh 69722 evaluation ( from 2000 to 2500 meters ) and if this will be causing any delta versus my assumptions ( 1800 meters and 30 knots currently ) than this will cause a new set of references on my work to be fine tuned but still very possible.
This is of course not true for Mr. Winklareth that will move from a current impossible scenario to one that will be even worst.

Hope to have explained the matter clearly enough, since you were still referencing to both scenario's ( to me the Mr Winklareth one is out of any possible logical consideration now ).

I cannot reach you with my e-mail, you need to work on your anti-spam I suppose to allow me to write you as far as I can see from the response I got.

Ciao Antonio :D

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José M. Rico
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Post by José M. Rico » Thu Feb 24, 2005 3:38 pm

Robert J. Winklareth wrote:Hi Jose,

... You can ignore the facts, but that will not serve the high goal of seeking the truth in the matter.
Antonio's battle reconstruction is not perfect of that I am sure, but honestly Bob when you go and say that the only evidence supporting his theory are the six photographs shown in their original "reversed" orientation, I think you are the one who is ignoring facts.

To Randy and George: Enough of all this already. The whole board is tired of your nonsense. If you guys force me to lock yet another topic, you both will be banned for a month from the forum. Just grow up and move on.

George Elder
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Yes, enough is enough.

Post by George Elder » Thu Feb 24, 2005 6:42 pm

Hi Jose:

Yes, the game with Randy grows tedious, and I agree to stop pulling his wings. I think it best that he not respond to me and I not respond to him. The profound and intractable antipathy between us is too much to bridge, and it certainly clouds the discourse.

Antonio:

My spam filter is nuts. Just post the first few letters of your e-mail address on this board, and I'll try to figure out how to fix the problem.
With regard to speed estimates, I think Foeth has given very good reasons why we cannot calculate with great accuracy the Bismarck's velocity via the shell splash method. I am content that the ship must have been traveling at least 29 knots given all we know from the record. I am not yet prepared to say she was going at 30 to 31 knots, and especialy 31 knots. Beyound the ability of the ship to achieve 31 knots, there also comes problems related to max-power output vibration effects that can realley screw up fire control. Granted, warships will suffer these effects when pressed, and we're not sure how max engine outputs would effect Bismarck's FC because we have no trial data. But usually, the closer one gets to maximum engine outputs, the worse the vibrations -- or so I have been told.
As I have admitted, I am not at all sure how one can accurately judge the Bismarck's speed given what we now have available. I think we should search out a method that will have an acceptable error margin, say +/- 0.5 knots at most. That is a demanding standard, and perhaps it cannot be obtained. Yet you are very inventive, and I am sure that when the detailed material shows up, something will come to mind. One reason I want to consult these dynamics specialsts is to see what tools they could come up with -- if any.

Rob:

I know you have been called a coward, etc., and that was wrong. The people who did that shamed themselves and did little to foward the debate. But you certainly seem to question Jose's quest for the truth when you say he ignors the facts, and this is much akin to treating him with the same disregard as others have treated you. Antipathy moves us to say and do things that ill serve whatever points we are trying to make. Moreover, you, I, and others do not have time to waste in venting our outrage, yet we seem to do so -- time and again. But in our cases, there are precious few days that we can aford to waste.
I grow weary, but there is much to do. And here I am wasting time writing messages. If I were a true scholar, I would post a lot less and work a lot more on solving the problems at hand and finding the needed information. Enough said.

George
Last edited by George Elder on Thu Feb 24, 2005 10:58 pm, edited 1 time in total.

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Antonio Bonomi
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E-mails

Post by Antonio Bonomi » Thu Feb 24, 2005 7:26 pm

Ciao George and all,

I have several e-mails.

Anyway, here is my personal official one :

Antonio_Bonomi@Virgilio.it

and it is always attached on the closure of all my post on all forum's were I write, no problems, you can write me there.

Ciao Antonio :D

George Elder
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Already sent you a test mail...

Post by George Elder » Thu Feb 24, 2005 8:27 pm

Hi Antonio:

I can make no promises they will help, but we have two oceanographers at Penn State who have experience in modeling methods that may be applicable. I will try to explain the problem you're trying to solve, and then see if they can help. It is the beginning of a new semester here, so that is not a good thing. Usually, the summers are best for enlisting help. But I will give it a shot. Give me a day or two to work up a good contact letter. I'm an alumni here, so perhaps that will help a tiny bit -- well, one can only hope.
I truely do respect what you are trying to do, and perhaps there is a way to reduce the error margin. That seems to be a good focus untill we can find a better means of making a velocity determination. So out of asll this fire and sparks something good may arrise. I am hopeful.

George

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