Photo # NH 69722 distance evaluation

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Antonio Bonomi
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Distances

Post by Antonio Bonomi » Wed Aug 03, 2005 7:31 pm

Ciao Marc and all,

no problems Marc :D

You wrote 10.4 I did 10.5, .. on reality it was 10.6 as you wrote to and you are the correct one in this case :D .

Here some material for everybody to enjoy the calculations on this photo if they like, thanking Jose' for the space provided for this material to be posted :

http://www.kbismarck.org/photos/measures.jpg

http://www.kbismarck.org/photos/BS-proportions.jpg

http://www.kbismarck.org/photos/PG-turretD.jpg

http://www.kbismarck.org/photos/PG-turrets.jpg


lets see the next steps, .. I am really curious.

Ciao Antonio :D

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Herr Nilsson
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Post by Herr Nilsson » Wed Aug 03, 2005 9:28 pm

Hallo Antonio,

Thank you for providing me the material.

OK, let's start: take a look at http://www.kbismarck.org/photos/PG-turrets.jpg

The distance between the centers of the barrels is 2,16m.
Have a look at the top view: There are 84 pixel distance between the barrels.
Have a look at the side view: There are 64 or 65 maybe 66 pixels of the lateral surface. 66 pixel means that the thickness of the drawing lines is completely added to the lateral surface. I doubt this was the intention of the illustrator. I think 65 or 64 is the right value.

However, even if we use 66 we have

66*2,16/84=1,697 m

That's far away from 1,8 m.

Gruss

Marc

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Antonio Bonomi
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Distance and photo evaluation

Post by Antonio Bonomi » Thu Aug 04, 2005 9:42 am

Ciao Marc and all,

OK, good to know you have received the material so we can always refer to something similar while progressing :D .

No problems for me if at the end it will end up been 1,65 meters.
We need to come as close as we can to the reality, unfortunately we do not have available the precise drawing to refer to and make this more easy.
My initial evaluation was 1800 mm so 1,8 meters, but like for the 10.5 meter distance I can be wrong and the real number when better evaluated can be different, on that case we found the measure right on the drawing itself as you may have noticed.

This is why it is so good to have more than one assesment and evaluation and reduce the tolerances as much as we can :D .

I see your point on that drawing using the pixel calculation methodology.

If I remember well last year when I made the calculation I was using the other drawing ( D turret ) and using the 2500 mm total height of the turret I made a proportion for the side turret plate and came out with 1800 mm.

You may want to do the same as the drawing is bigger and confirm your current evaluation, as said really no problems for the measure you will come out with.

On this photo there are so many tolerances that will play a big role later for the whole distance calculation that we must try to come close to the real measures available as much as we can and you are doing a good job my friend, as usual :D .

The biggest difficulty will be the Bismarck shadow correct evaluation.

Please let me know if you need anything else I can provide you.

Ciao Antonio :D

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Patrick McWilliams
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Post by Patrick McWilliams » Thu Aug 04, 2005 10:01 am

Antonio,

Can anything about the gap to Bismarck be devined by the length of Prinz Eugen's stern wake?

In the largest version of the picture, Bismarck appears to be 'not far' behind the point where the wake comes to an end; but of course that might be misleading as that point is very much in the background of the photograph.

Regards,

Patrick

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Herr Nilsson
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Post by Herr Nilsson » Thu Aug 04, 2005 4:00 pm

Hallo Antonio,

I already calculated the height of the vertical side based on the D-turret picture yesterday evening. The result was 1,59 m +/- 1 cm. I checked it two times. My problem is, that I really don't know wether the edge of the front turret plate is in line with the edge of the vertical side or not. It seems so, but I'm not really sure. :think:

Gruss

Marc

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Antonio Bonomi
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Measures

Post by Antonio Bonomi » Thu Aug 04, 2005 6:25 pm

Ciao Patrick, Marc and all,

@ Patrick,

your observation of the Prinz Eugen wake is very clever :D

In fact that wake as we know from other photos too was remaining on the sea for quite a long time, .. and here we can assess a couple of minutes at least.

No, unfortunately I have no idea on how to use it to make this evaluation.

@ Marc,


Ok, I had no doubt knowing you that you did it already my friend, maybe some good photos of teh Prinz Eugen turrets can help you.

Check your mailbox and let me know if they work for the need :D .

Ciao Antonio :D

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Herr Nilsson
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Post by Herr Nilsson » Fri Aug 05, 2005 2:11 pm

Hallo Antonio,

once again, thank you for the additional material, it's very helpfull!

I would like to ask you for two additional pictures (if you have them at all), please:
1.: a (high resolution?) front view of Prinz Eugen's turrets.
2.: the NH 69722 picture from the Busch book without markings or a similar high resolution picture of NH 69722.

I've used the pictures you've sent me to calculate the height of the vertical side of PE's turrets once again, but my result is always 1,65m +/- a few centimeters. To shorten this cat-and-mouse-game :wink: , please tell me how you reach the conclusion that the lateral surface is 1,8 m.
I'm pretty sure I found your error in reasoning, but I can't help you, if I don't know what you did.

Thanks in advance!

Gruss

Marc

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Antonio Bonomi
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Measures

Post by Antonio Bonomi » Fri Aug 05, 2005 3:01 pm

Ciao Marc and all,

good to know it helped :D .

OK I will send you what I have right away.

Missing a very good drawing of Prinz Eugen ( on enlarging the ones I sent you I have wrongly evaluated 1800 mm with the proportions ) I have checked the Admiral Hipper ones ( from AJ-Press Morskie books I have, 3 monography and one dedicated to Adm Hipper ).

I think I have found something interesting :D .

They do have into those book reproduced the original drawing of Admiral Hipper ( F. Krupp-GermaniaWerft ) on scale 1/100 so they proved to have it in their hands as it is reprinted in the book attachments.

Than they have as usual made very good new drawings on scale 1/200 of the ships.

The measure they have used is 8 mm on scale 1 /200 so I assume 1600 mm on the reality is the real value ( and on the scale 1 / 100 they have it shod have been 16 mm ) and you are very close and much closer than my initial estimation.

So I think we can assume 1600 mm as the most close value so far.

As usual you have done a good job, bravo :clap:

So right now thanking you we have 10.600 mm and 1600 mm as good enough values.

Now the difficult one, the Bismarck shadow evaluation my friend.

I will scan tonight the Adm Hipper drawing and send it to you so you can see it if you do not have it.

Ciao and bravo again Antonio :D

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Herr Nilsson
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Post by Herr Nilsson » Fri Aug 05, 2005 7:57 pm

Hallo Antonio,

unfortunately the AJ-Press drawing is not very accurate. 1,55 m is to low in my opinion.
The most accurate picture is the D-turret picture. http://www.kbismarck.org/photos/PG-turretD.jpg
I calculated the height of the upper front edge and got the result of 1,59m as I mentioned before. Unfortunately the upper front edge is not in line with the side edge (that's the reason why I asked you for a front view of the turret).
Before I calculated the difference by means of this front view picture I eypected myself a difference of 1-3 cm, but it's 6 cm . So it's once again 1,65.

Gruss

Marc

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Antonio Bonomi
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Measures

Post by Antonio Bonomi » Fri Aug 05, 2005 9:22 pm

Ciao Marc and all,

OK, I see.

I think we can be satisfyied with this measure you obtained which is very close anyhow and I agree with you my friend.

What about taking your 1,65 meter ( 1650 mm ) and move on ?

I am really curious to see your evaluation of the Bismarck shadow as your inputs so far are providing a lot of value add as usual.

So lets agree about 10, 6 meters ( 10.600 mm ) as the distance between the 2 turrets ( we found it on the drawings ) and 1,65 meter ( 1650 mm ) as the vertical plate dimension as for your measure.

Let me know my friend :D

Ciao Antonio :D

marty1
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Post by marty1 » Tue Aug 09, 2005 12:05 am

I have been working through the range problem. Interesting challenge.

I wanted to ask a question about the photographers position when he took the photo of interest. If the position indicated by Antonio in his plan view is correct, should not there be a flak gun mount very prominent within the foreground of the photo. This gun mount doesn’t show up on the photo being discussed – at least I can’t make out any aspects of this flak gun. Was this flak gun mounted in the position shown on the various Prince Eugene plans at the time of this operation? If it was in place at the time of the photo, shouldn’t it show up in the foreground of the photo of interest?

The reason I ask is, I am wondering if the photographer was actually much closer than 16.5meters to the closest 20,3cm Gun Turret.

Image


Image

Both photos are from: http://www.prinzeugen.com./PGWeapons.htm

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Javier L.
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Post by Javier L. » Tue Aug 09, 2005 12:54 am

To marty1:

I see your point but on the photo being discussed the photographer is looking aft and not towards the forward section of the ship like the photos you show.

But I think your point is valid too for Photo # NH 69722. If you look carefully to the right, the shadow of a man can be seen. In my opinion this man is the gunner of the 20 mm Flak. The Flak can't be seen because it is obscured by the man, and only a wheel is seen.

Image
look at the man's shadow to the right of the photo.

Image
look at the flak wheel.

Image
look at the flak wheel to the right of the photo.

marty1
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Post by marty1 » Tue Aug 09, 2005 2:38 am

My bad. I assume the splinter shields were added to the flak guns at a later date?

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Antonio Bonomi
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Photo Nh 69722

Post by Antonio Bonomi » Tue Aug 09, 2005 9:57 am

Ciao Javier, Marty and all,

sorry to have created some confusion using partial drawings and also not correctly timed ones.

I beg you pardon :oops:

Let me try to explain were the problems is and set some clear understandings.

The Prinz Eugen main turrets we are looking at are the aft ones ( C and D ) so the photographer has taken a photo of Bismarck following Prinz Eugen while he is on the aft starboard section of the Prinz Eugen.
Both ships are firing to port side to the enemy ( Hood and PoW ).

Mr. Lagemann ( the photographer name ) member of the PK-Propaganda Krieg organization is on the platform were the aft starboard 105 mm heavy anti-aircraft gun was ( the gun was trained outboard on that moment ).

Between that platform and the C turret at that time ( May 1941 ) there were 2 cabinets and the single 20 mm A/A gun that Javier properly posted with that wheel and the man handling it, both visible on the photo.

The fixed railing was up ( of course ) while all the moveable railings were taken down ( clearly visible too ).

It was my fault ( and I beg you pardon again :oops: ) to use a more recent drawing ( the only one I had on that moment ) of the Prinz Eugen that showed that ship part after some A/A guns change on 1944 and consequently on the drawings and on recent photos you see there instead of the 20 mm single that was there originally a new weapon that is a 40 mm bofors with anti-splinters shield ( one is visible also on top of C turret while nothing was there on May 1941 ).

Clearly it is not the same gun :D

I will make a better set of drawings and post it soon so we will get read of this potential source of confusion.

Here you can find correct 1940 plans of Prinz Eugen were you can see what I am stating.

http://www.dreadnoughtproject.org/plans ... Eugen_1940

Again excuse me for having not thought about it :oops:

Anyway, welcome on board on this intriguing discussion ... hope you will enjoy it like I do :D

Ciao Antonio :D

turlock
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range estimation

Post by turlock » Tue Aug 09, 2005 10:42 pm

Thanks for a great post! This one really messed with me. I used the full picture to base my judgements, but the perspective is different from the first photo submitted. The photo is not very clear but I based my judgements this way.
I am a small boat sailor and sometimes find myself having to gauge the approach of much larger vessels to determine if we may be on converging courses. The horizon at sea level is two miles, and my head is usually about two meters off the water. I'll have to estimate the freeboard aft on Prinz Eugen at 6 meters , but I don't know what it really was, so using this grainy photo I estimate that part of Bismarck's hull could be hidden by the horizon when viewed from the cockpit of my boat. Also, the outer approach channel to my home port is three nautical miles long and the marker at the other end about seven meters high. Seven meters is not very high when viewed from that distance, and the marker can be hard to see in haze.
Now take Bismarck, whose hull I estimate would be partially hidden from my usual conning level, and throw in the scale on the big yachts, as well as tug boats I regularly see plying that channel and I'd say she is 2 to 3 nautical miles away...the long wake from Prinz notwithstanding. An 18,000 ton cruiser moving at 30 knots will leave a long wake. Even 80 foot motoryachts do.
The clouds of gun smoke can be longer than the ship herself. Finally, the pusher boats that are common in the Potomac River and Middle Chesapeake are hardly the size of Bismarck, and yet look like the photo when they are over a mile away. Optical distances viewed over the water from close to sea level are decieving, and objects are often further away than the sailor thinks. A missile frigate from 2 miles is a big ship, viewed over the water, and such a ship is a far cry from Bismarck's massive profile.
My channel marker, seven meters high, sitting next to the image of Bismarck in the full photo, at three miles would be about to the scale it usually appears at three miles.

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