Photo # NH 69722 distance evaluation

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Antonio Bonomi
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Photo # NH 69722 distance evaluation

Post by Antonio Bonomi » Sun Jul 31, 2005 1:06 pm

Ciao all,

since I am starting a couple of weeks of well deserved vacations, I took back my study on the famous battle to enjoy my hobby :D .

Here a question we have left on the table, what is your evaluation of the distance between Prinz Eugen on the lead and Bismarck on the back on this photo which shows the first salvo fired by Bismarck to Hood at 05.55 ???

Image

I have worked a bit on it with some friends and Bill Jurens, so I guess some progresses maybe have been made lately.

Please no enlargement on the whole battle argument as for that there is a dedicated post like everybody should know, so just stick on the question of the photo evaluation of distances.

It is mainly a photogrammetry or trigonometry type of question for the ones that do have this type of skill and competences.

NOTE : The photo showed here is a reduced version, on the full one there are more parameters to help the whole assesment.

Ciao Antonio :D

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Ulrich Rudofsky
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Post by Ulrich Rudofsky » Sun Jul 31, 2005 4:38 pm

I cannot resist to add my 2 cents worth. Without trig or math, my uneducated eye would guess that the distance is about 2500 - 3000 m. I assume that there is no use of telescopic lenses etc.
Ulrich

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José M. Rico
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Post by José M. Rico » Sun Jul 31, 2005 7:58 pm

Here is the full version of the photo if it helps.

Image

hsk1
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Post by hsk1 » Mon Aug 01, 2005 9:11 pm

Hola!
I would say the distance is 1000-1300m.
Not much more.

MfG hsk1

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Herr Nilsson
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Post by Herr Nilsson » Mon Aug 01, 2005 9:21 pm

Hi all,

here's my try.

Assuming:

height of Bismarck 36m (22 pixel),
vertical side of Innsbruck (C) and Wien (D) 1,65 m ( 193 pixel and 111 pixel),
distance between Innsbruck and Wien 10,6 m

Using a formular for distance measuring by a speed camera :wink: follows that the distance between camera and Innsbruck is 14,36 m and the distance to Bismarck is 2749m. ( +/- 200 m: the accuracy of measurement in such a picture is of course not very well. :( )

Gruss

Marc

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Post by Monitor » Mon Aug 01, 2005 11:17 pm

What is Innsbruck and Wien?

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Ulrich Rudofsky
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Post by Ulrich Rudofsky » Mon Aug 01, 2005 11:33 pm

Prinz Eugen turrets were named after Austrian towns from stem to stern: Graz, Braunau, Innsbruck, Wien.
Ulrich

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tommy303
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Post by tommy303 » Tue Aug 02, 2005 3:57 pm

I believe the choice of city names comes from the victories achieved by Prince Eugene of Savoy, if I am not mistaken.

trf

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.

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_Derfflinger_
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Post by _Derfflinger_ » Tue Aug 02, 2005 4:33 pm

For the record, can anyone provide the turret names for Hipper and Blucher? Did they have similar "names of meaning" or were they the usual alphabetical designations?

TIA.

Derf

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Antonio Bonomi
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Distance of Bismarck

Post by Antonio Bonomi » Tue Aug 02, 2005 11:42 pm

Ciao Marc and all,

nice talking again to you my friend :D

Here some correct parameters :

Height of Bismarck from waterline to top rangefinder was 33 meters ( but please consider Bismarck hull been deep on the water due to her load on that moment ), so be careful on evaluating her shadow proportions ( hull and upperworks on the right way ).

Vertical side of C and D turrets are the same and are precisely 1800 mm ( 1.8 meters ).

Distance between C and D turrets was 10.5 meters precisely ( from Prinz Eugen original drawings ).

Presumed position of the photographer ( Propagand Krieg PK Lagemann official Prinz Eugen photo reporter ) was 16 meters from C plate and 26.5 meters from D plate.

Photo camera a Leica 50 mm fixed focal lenght of 1934-1938 model.

I am sure you can provide as usual a lot of value add my friend.

Ciao Antonio :D

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Javier L.
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Post by Javier L. » Tue Aug 02, 2005 11:52 pm

Antonio are you sure the vertical back side of C and D turrets is the same? In the Hipper Class, A and D turrets were a bit different than B and C turrets because A and D didn't have the rangefinder.

And the distance of 10.5 meters between C and D turrets, is it from center point to center point of the circular babettes?

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Herr Nilsson
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Post by Herr Nilsson » Wed Aug 03, 2005 10:18 am

Hallo Antonio,

Bismarck's height: 33m? I can live with that, no problem. I choosed a little bit higher value to compensate a few effects. The first one is pitching and the second one is the effect that the masts possibly let the ship appear a little bit higher than it really is.
However, 33m is OK.

Vertical side of C an D turret (Innsbruck and Wien caused a little bit confusion, sorry about that):

Hm, I checked this three times on pictures and plans, but I always get the result of about 1,65m. The accuracy of measurement is of course unsatisfactory, so I have no problem with a few cm more or less, but in my opinion it is definitely not more than 1,70 m. :negative:
By the way, in my opinion the bottom side of C seems to be visible, what do you think?


Distance between C and D:

The distance of 10,60 m comes from the plans of http://www.prinzeugen.com. The readability of this plans is not very well. In my opinion there were two possibilities to read the value of the distance 10,50m and 10,60m. Therefore I've checked this and have come to the conclusion, that 10,60 is matching significant better.
I'm a little bit surprised at the value of 10,40 m. :? Anyway, if you have the original plans, no problem 10,40m is good for me.

With the values,which you prefer, we get:

camera distance to C: 14,38 m
distance to Bismarck: 2302 m


Hallo Javier,

I'm refering to the side of the turrets not the back sides. The vertical side should have the same height for C and D.
Assuming C and D are firing at the same target, their sides are parallel. Therefore the distance between the visible sides should be the same like the distance between their center points.
But you make me think of the fact, that the camera and D are not in the same level, therefore the distance should be a litte bit greater than the value of the plans. :think:


Gruss


Marc

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Antonio Bonomi
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Prinz Eugen parameters

Post by Antonio Bonomi » Wed Aug 03, 2005 4:19 pm

Ciao Marc, Javier and all,

Javier,

do not run the risk to wrongly evaluate the full turrets height, which is as you said different between C and D as C was taller than D.
Both turrets had a lateral side plate that was the same on both and did not reached the back of the turret on both.
On the photo you can see clearly the D one and you can correctly estimate the same on C under the tube you see on the side.
Those 2 plates were 1800 mm height, so 1.8 meters.

Marc,

I will send you some drawings so you can control the 1800 mm versus the 1650 mm you are estimating on drawings as measure for those plates height.
My drawings are taken out of Schmalenbach book ' Prinz Eugen under 3 flags'.
Make your measurements on those and let me know the measure you come out with, no problems.
Bottom and top side of C plate is difficult to realize, I have better detailed photos I will send you to see it.


OK for Bismarck height at 33 meters when fully loaded, it could have been 34 when empty or very light, but we do know she was very full on that moment.
The real problem is to establish the correct point in the water were you take the measurement for the bottom of the shadow as Bismarck hull is partially immerged on the water been below the horizon waterline.
Due to heavy sea of the ocean the front wave is partially covering the hull so you must consider to take a piece of water as baseline for the measurement to take the correct 33 meters reference.
Hope my explanation is clear enough, to understand what I mean you shoud compare this shadow with other Bismarck shadow on photos taken upfront so you can correlate measurement points.
I will be sending you something about this as well.

You are right about the 10.6 meters as distance between the 2 turrets.
I wrote 10.5 based on my memory and I was wrong.
On the drawings is clearly stated 10.6 meters. Bravo ! :D

The 2 turrets on the photo are turned 20 degrees forward the beam ( which was 270 ) so on bearing 290 degrees.

Lets see with those latest references what comes out now.

Ciao Antonio :D

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Herr Nilsson
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Post by Herr Nilsson » Wed Aug 03, 2005 4:23 pm

Hallo Antonio and all,

it seems I was a little bit mentally deranged, while I was writing my last post. Antonio, you never talked about 10,40 cm. :oops: I'm very sorry. I didn't want to confuse anyone.

Gruss

Marc

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Antonio Bonomi
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Post by Antonio Bonomi » Wed Aug 03, 2005 4:24 pm

Ciao Marc,

I need you to write me an e-mail, I have lost your e-mail address on my portable PC and I am far from home and my house PC, sorry :D .

Ciao Antonio :D

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