Photo # NH 69722 distance evaluation

[Antonio Bonomi]

Ciao Marty and all,

no problems for the material, it is all well known documentation I have in good enough quality and it is absolutely necessary for any study one would like to make on the subject

No, I have never done the estimation of the shell case distance, if you need it I can try. Same I think applyies to Marc as we naver worked on the second photo were the shell case is, just on the Nh 69722 for Bismarck real distance evaluation.

YES that is a very well known photo of Bismarck during refuel training with Prinz Eugen ( as many were ordered by Adm Lutjens ) on the Baltic sea.

It is this one :

http://www.kbismarck.com/bismarck5.jpg

I have never tryied before the evaluation of the Bismarck distance on this photo that is taken exactly from the same 105 mm platform as the shell case one, but not on same position of the Nh 69722 ( first salvo ) one.
Obviously all photos always taken by Mr. Lagemann.

Those 2 photos are taken with Lagemann on the external border of that platform very near to the fixed railings, while Nh 69722 was taken with Lagemann on the other side of the platform and the 105 mm gun, close to the upperworks, on the inside of the ship.

So what I did is to compare this one of the refuel training with your evaluation of the shell case one you evaluated 1200-1300 meters.

By simply printing the 2 photos on the 5x negative format I was able to make my estimation.

I use often this fast system that is based on the enlargement close to the 120x180 mm format of a photo that is based of course on the base 24x36 mm negative, so 5 times enlarged.
Often you are not able to make it perfect 120x180 mm, because they cut the photo on printing, but you can come fairly close to it.
With this raw estimate method, knowing it was always a 50 mm fixed focus camera you can make good estimations on many photos.
But again, here the real expert is Bill Jurens.

Anyway, comparing the 2 photos with this method I came with a measure of Bismarck shadow that is 4,2 times bigger on the refuel training photo than on the shell case one.

This means 4,2 times less distance and consequently 285-310 meters.

No, I do not know the typical refuel distance used, but I think the distance looks ok to me around 300 meters at first look.

Of course doing the exercise on the other way around and using this photo as reference to calculate back the other 2 is a very interesting study case as well.

Ciao Antonio

[Ulrich Rudofsky]

the typical refuel distance used, but I think the distance looks ok to me around 300 meters at first look

That looks like a very long fuel line length to me. Three soccer fields? I would cut that in half.

[Antonio Bonomi]

Ciao Ulrich and all,

Good point my friend !!

I think I better explain in more details.

The 300 meters we are evaluating are between Lagemann position on the Prinz Eugen 105 mm aft starboard platform and the Bismarck main tower.

From Lagemann position on Prinz Eugen till Prinz Eugen stern end there should be around 70 meters ( 71 m I have measured on the drawings ).

From Bismarck bow till main tower top there are around 100 meters ( 107 m I have measured on the drawings ).

So if we are only referring the distance between Prinz Eugen stern and Bismarck bow obviously we have to make the calculation of 300 minus the 70+100= 170 meters.

That brings the refuellling distance around 300-170= 130 meters, and I think we are close to what you are saying.

Did I get the point right ?

On the other 2 photos this factor is not so important given the distances we are talking about been 1300 and 2400 meters, but on this one I think it plays a very important role.

Ciao Antonio

[marty1]

I finally sat down and crunched through my numbers for the refueling photo. I get an angular height of Bismarck to be about 130-mils. I think Bismarck’s is ridding a bit higher out of the water than has been assumed previously. The waterline at the bow is fairly clear. I therefore obtained a vertical height of a little higher than 34meters. That puts my range estimate from Lagemann’s presumed position to the main tower top of Bismarck to be about 265-meters.

Accounting for distance from Lagemann to PE stern, and the main tower of Bismarck to Bismarck bow, my final range estimate from Bismarck bow to PE stern to be about 85 to 90 meters. That seems pretty bloody close. Your 130meters seems more realistic for some reason – although I have no idea what sort of distances would be realistic for refueling.

After reading your methodology for determining range, it would appear that our methods are very different. I need a reasonable guess at where the photographer is set in order to establish a relative scale for the photo. I also need to establish size of forground features – the more the better. Doesn’t sound you are having to go through either of these steps.

I have an unrelated stupid question. It looks to me that in the first two photos we examined the handrails are "not up" on the Prinz Eugen. However, the handrails are clearly present in the refueling photo. Was it typical to take the handrails down when a ship cleared for action?

[Antonio Bonomi]

Ciao Marty and all,


YES, the waterline of Bismarck on the refuelling photo is a lot more visible and you did right assuming her been 34 meters and not 33 meters of height.

That was due to the fact that Bismarck was not fully loaded as she was during Op. Rheinubung.

YES, our methods differs for some base assumptions but it is very good we are coming out pretty close given the tolerances, and of course 2 or more methods giving similar results are better to have a final evaluation call on those subjects.

I do not know the typical distance for refuel but 100-150 meters looks pretty reasonable to me as 2 ships like that cannot stay more close one to another while sailing.

You are a very acute observer .

The Prinz Eugen handrails is one of the key to understand the whole set of Denmark Strait photos as they were different and differently positioned on the ship during Op. Rheinubung and the ' clear for action'.

On Prinz Eugen there were 2 type of handrails : Fixed ( all metal and not foldable ) and foldable ( metal post with holes and chain inside ).

For example around the 105 mm guns platforms there were fixed handrails ( railings ) but also on other parts of the ships on the upperworks at midship.

The remaining were foldable ones and mostly were taken down during actions as you can see.

Some at midship were left up as we can see on some photos.

The exact re-construction of the handrails configuration on Prinz Eugen during that operation is one of the key to understand from were Mr. Lagemann took the photos and from were the PG Film was recorded.

So the answer to your question is YES, the foldable ones were taken down during actions ( not all ) and it was typical for KM warships.

Ciao Antonio

[Ulrich Rudofsky]

"I do not know the typical distance for refuel but 100-150 meters looks pretty reasonable to me as 2 ships like that cannot stay more close one to another while sailing"

That is probably a very good distance estimate. According to "Seemannschaft" Gladisch & Schulze Hinrichs, 1943, ...........the lead vessel extends to the receiving vessel the towing cable/oil hose that is 150 m in length (for two destroyers)...........it is attached to a 50 m manila retrieval line to which floats are attached on both ends......

It is likely that this oil transfer set up was a standard procedure.

[marty1]

At the risk of diverging further from the intent of the thread -- but why were the foldable handrails taken down when a ship clears for action?

[Ulrich Rudofsky]

You know, that is a very good question. I often wondered. I don't know the official explanation, but things like cabin walls etc. were even knocked down on sailing ship and ship in the sail-to-steam age. Furniture was taken below, or more often just tossed over the side. I think that taking down the railings for action had to do with clearing debris, unexploded shells, dismounted guns, and anything hot or on fire off the deck, even dead or nearly dead sailors, if need be.

[mac.one]

Hi
Was it not to prevent damage from the blast from the guns?
Cheers Julian

[marty1]

Hi Ulrich

Yes I recall from days of reading Hornblower, C.S. Forester's descritpion of down the Captian cabins walls and such whenever a ship cleared for action. It just seemed odd to haul down safety rails, but as you and Mac-One suggest, I'm sure there was a very good reason for this activity.

Antonio:

You indicated in a post above:

"Often you are not able to make it perfect 120x180 mm, because they cut the photo on printing, but you can come fairly close to it.
With this raw estimate method, knowing it was always a 50 mm fixed focus camera you can make good estimations on many photos."

When you say 50mm fixed focus camera -- does that mean that the camera Lagemann was using had a fixed focal length of 50mm?

Thanks
marty

[Antonio Bonomi]

Ciao Marty and all,

YES !

The base assumption we are using is that Mr. Lagemann was equipped with a camera having a lens with fixed focal lenght of 50 mm=5 cm ( standard for all the PK - Propaganda Krieg members ).

One camera very similar to those Leica :

http://freeweb.supereva.com/sergio7858/ ... che.html?p

looking at the 1934 model and you will be able to read the focal lenght into the lens itself ( you will read f=5 cm that is 5 centimeters equivalent to 50 mm ).

Here in :

http://freeweb.supereva.com/sergio7858/IIg1934.JPG

When I was in Bundesarchiv-Freiburg in last May I have also seen the typical movie camera they used during the war and I can confirm also the film used at that time was a 35 mm one, basically the same one used to make photos with the camera.

This means that finding the original 35mm PG Rheinubung film one will have one photo negative ( 24 x 36 mm ) of every single film photogram.

Now you can imagine if we will be able to find the original not censored version of the Denmark Strait battle film what we can do with it, it should be some hundreds of meters for 20 minutes.

It is my dream

I am glad you have understood that to know more about those photos one must know well ( or at least have an idea ) of the equipment used to make them.

I went thru same learning process myself of course .

I hope my explanation is good enough but I am sure there are persons that do know more about the characteristics of those equipments.

Ciao Antonio

[Ulrich Rudofsky]

These "50 mm" lenses: actually, Leitz Leica Elmar was 51.6 mm, Zeiss Contax was 52.3 mm. I don't know if those few percent would influence your calculation. How do you handle depth of field? In the bad lighting in the morning, the aperture must have been with open.

[marty1]

Antonio:

I think I understand your approach to the range estimation problem – “maybe”.

The scale factor is simply the height of the Bismarck image on the 24mmx36mm negative divided by the actual height of the Bismarck. The range to Bismarck is than simply the focal length of the camera divided by the scale factor.

Obviously we are not measuring directly from the real negative, but instead we are measuring from an actual photo or a blow-up of a photo. So we need to know the size of the negative relative to the print or image we are using.


Is this the methodology you are using?

Regards
marty

[Ulrich Rudofsky]

The 35 mm measurement of a German negative is 24 x 36 mm, as far as I know. The print you are going get from an enlarger is anyone's guess unless you can see the proof sheet.

[Antonio Bonomi]

Ciao Marty, Ulrich and all,

YES, I think you got correctly the point.

I am using a 5x ( 5 times enlargement of a negative that as Ulrich properly confirmed is 24x36 mm) so I am measuring on a 120x180 mm enlargement photos ).

Since I do not have the negatives I had to try to recreate the photos as best as I can from available prints.

It is not 100% perfect since I miss the negative, but at least having what I suppose are the best and most complete prints of all photos I can come very close and mostly I can measure and compare the Bismarck distance from Prinz Eugen thru the entire set of photos.

Thanking my friend Bill Jurens ( the photogrammetry real expert ) I am than using the methodology you just correctly explained.

This is based on 4 parameters :

1) the negative heigth of Bismarck ( I measure on my 5x photo and than I divide by 5 of course to simulate the negative ).

2) the real ship dimension ( height been 33 meters for example )

3) the focal lenght which is 50 mm

4) the range ( distance of the Bismarck from the camera )

knowing 3 out of those 4 I can have the 4th one ( usually I need the range ).

The scale factor is 2 / 1 just as you explained, than you multiply by 3 and you have 4.

Ciao Antonio