Bismarck at DS after the second turn

[Antonio Bonomi]

Hello everybody,

@ Wadinga,

I can easily understand that you like to solve the enigma of Brinkmann incorrect distances evaluation toward PoW written on his map and utilized also by Reimann later on to justify himself with Schmundt.
All this has been clearly pointed out by Vize Adm Schmundt on his report and on the responses too.

But the above has nothing to do with the real Prinz Eugen run track, never put in discussion by anybody.
Here there is one irrefutable fact and it is that Jasper distances were the correct ones, just as confirmed by Schmundt too.
This is more than obvious since Jasper hit twice the Hood and 4 times the PoW shooting his guns with his own evaluated distances.
There is no need here for other confirmations, since we have Jasper report distances available.

Consequently, as far as the battle map re-construction goes, we do have the set of correct distances and the correct track of Prinz Eugen to be utilized for the map re-construction purpose.

I wish you a good luck on finding the other document ( Prinz Eugen B. Nr. G 2243 of 12.7.1941- only sent to the Commander of Cruisers ), and to solve the Brinkmann incorrect distances enigma that can be very interesting indeed as far as the potential solution and I have my own idea about it since years.
The fact that Reimann used the Brinkmann incorrect distances and realized his own incorrect PoW track on his torpedo map for the response to Schmundt, once realized as you should have done by now, becomes even less important for our purpose.

Meanwhile, do you agree that only the Jasper distances between Prinz Eugen and Hood and after PoW are correct and the Prinz Eugen own track on her own battle map is correct as well, so we can move forward ?

Bye Antonio

[wadinga]

Hello Antonio,

You again seen to me to have things the wrong way round.

The fact that Reimann used the Brinkmann incorrect distances and realized his own incorrect PoW track on his torpedo map for the response to Schmundt, once realized as you should have done by now, becomes even less important for our purpose.

You say Reimann used Brinkmann's values whereas surely the exact opposite is true. Reimann has more values, one every minute after 06:00, so where did the additional ones come from? Brinkmann has only one shared value, at 06:00. You say "his own incorrect PoW track" of Reimann's sketch, whereas your own deduction of the consistent 4100m offset from the accurate combined rangefinding which allowed Jasper to score hits, suggests his estimated track is more accurate than Rowell's created months after the event. If Rowell's track is incorrect then the start points of his salvo plan's ranges are incorrect and his guesswork of Bismarck's track is even less precise.

If Reimann slavishly follows anything it is the PG track of the Gefechtsskizze and maybe this is the source of any errors.


All the best

wadinga

[Antonio Bonomi]

Hello everybody,

@ Wadinga,

it seems that we are having different opinions about who did use for the first time on a map the surely incorrect distances between Brinkmann and Reimann, but that is OK for me and we can only try to solve this problem finding more official German documents and information, just as I am currently trying to do in order to solve this enigma and verify my personal intuition about it.

Any help by anybody on this research is more than welcome of course.

It is since many years that we are talking about the distances accuracy evaluation from both sides of this battle, and I have spent years trying to re-construct more precisely this battle map starting mainly from the distances, ... unsuccessfully.

The paradigm shift on the efforts occurred when you and Dunmunro suggested me to use the bearings to do it instead of the distances and only use the distances as a verification parameter after the bearings were OK, obviously everything with due tolerances.

The bearings, we all know do have a much less tolerance factor and that worked perfectly as you should have realized by now.

This is the reason why on the early part of the battle I care less about the accuracy of the Bismarck track showed on PoW gunnery plot later used by Rowell to realize the Bismarck track on his produced map, as it is self evident.
PoW gunnery plot on the Bismarck track becomes more precise and reliable after the started scoring hits and in fact it goes from a 210° estimated course of Bismarck, to a 225° estimated course of Bismarck, still not perfect but surely more precise.
Rowell used the distance and the bearing on his produced map for the Hood second board taking them directly from the PoW gunnery plot, as you can verify, with a minor adjustment of the distance from 16.450 yards to 16.300 yards, ... with the same bearing.

Both Reimann and Brinkmann made many errors on their maps referencing the enemy distances and depicted track as it is very evident, the only usable parameter are the bearings to the enemy, and in fact I am using only those.

Maybe one day we will realize more about it, ... but again, ... for this exercise we are making what counts are the correct distances between Prinz Eugen and Hood/PoW and we have them from Jasper report, and the Prinz Eugen correct track and we have it on her own battle map.

To make a long story short, using the bearings both sides we can only assume being reliable the distances from both sides gunnery officers ( Jasper and McMullen ) for the simple reason that they were scoring hits on the enemy warships, so those were the most correct distances evaluation for sure.

Bye Antonio

[Bill Jurens]

This seems to be a useful and productive discussion so far, When figures and methodologies differ, it IS often difficult to determine precisely what set of numbers, or interpretation is most reliable. Patient and respectful discussion -- as we are seeing here -- usually does enable some sort of consensus to be found, however. If we do hit a wall here, perhaps we can move to a somewhat different place and try to drive in a wedge there instead.

So far as ranges are concerned, I remain a bit uncertain as to exactly what sorts of ranges are being quoted in various sources. For navigational purposes, the answer is simple enough -- it's the actual distance over the water -- but with gunnery things are often somewhat different, i.e. gunnery people might actually be using, and quoting so-called 'gun ranges' instead, because that's actually what is being displayed on their instruments. To take a (completely made up) example, for a variety of reasons revolving around the ballistics and alignments of the guns, etc., the firing ship may actually have to set the guns to a range of 14200 meters in order to hit a target which is, by navigational range, only 13800 meters away. But the former number, i.e. 14200 meters, is really the only one the gunnery officers are immediately interested in, and may well be the one they know, or remember, in subsequent reporting.

I am not sure how to clear up these sorts of difficulties insofar as the correction itself, i.e. the offset between gunnery and navigational range is often not permanently recorded, and it's very often difficult to tell with any certainty precisely which figure -- navigational range vs gun range -- is being quoted in any particular instance.

Keep up the good work!

Comments, as always welcome.

Bill Jurens

[Antonio Bonomi]

Hello everybody,

I have produced the situation at 06:00 to be verified :

viewtopic.php?f=1&t=8335&start=75#p81348

and I have showed the overall scenario once you correctly place the PG and PoW official tracks using the above reference positions at 06:00, drawing the Bismarck track close to the Prinz Eugen one with the known German evidence available and the correct bearing from the PoW to the Bismarck :

posting.php?mode=reply&f=1&t=8335#pr81391

So far I have received not a single correction request or a suggestion to change something that is assumed being an error.

If nothing will arise asking modifications I assume that everybody is fine with those reference showed and I will continue with the analysis I wanted to do having started this thread, ... after 06:06 battle time, ... because for me personally, what I have showed above is well known since 13 years already.

Thanks for the cooperation, ... Bye Antonio

[Bill Jurens]

I am not sure we actually have consensus yet. I, for one, would be interested in my questions regarding gun range vs navigational range.

Other correspondents??

Bill Jurens

[wadinga]

Hello Revered Moderator,

Indeed concensus is a difficult thing to achieve.


Reimann describes the things he draws as as "e" which is clearly some kind of range. Since the equivalent for him of gun range is truly enormous, as he will have to fire his torpedoes at something like 45 degrees (target angle) from the actual measured azimuth of his target, I believe "e" is actual navigational range. Jasper with a weapon transit time measured in seconds will have a very different "gun range". The only value worth sending to Reimann is actual measured range.

I hope we have achieved agreement, based on Reimann's KTB included statement, that he had the benefit of the best possible navigational range solution from the combined several 7m optical and radar units aboard Prinz Eugen. Thanks to Antonio's perceptive observation we can see that due to a transmission error, the value he recorded (and used) was 4100m higher than the real value. A simple electrical error results in him being unfairly pilloried, in my view. (Vorsprung Durch Technic , indeed) To dismiss the values he recorded would also be remiss I believe, since they are probably accurate but with a consistent 4100m offset from reality.


Rowell is clear he describes the ranges derived from the Dreyer system as gun ranges, ie as future predictions of where the target will be when the gun fires. Once again I observe, the map he produces for the August enquiry is nothing like the output from the Dreyer system. Target azimuth and gun range are recorded, but based on the output recorded in Padfield's Guns at Sea, own vessel course is not. Warship International had an excellent article on RN fire control systems, what can that tell us?

drawing the Bismarck track close to the Prinz Eugen one with the known German evidence available

There is little if any German evidence for Bismarck's position with reference to Prinz Eugen. Nothing in the PG KTB for instance. Merely observing that the two ships were "in line of battle" does not require that they were directly ahead and astern. Scheer's ships at Jutland were in "line of battle" but nearly collided with one another due to circumstances. Contrary to the geometrical assertions suggesting "line of battle" above, the photographic evidence shows PG and Bismack virtually side by side for much of the sequence, and proceeding at right angles to each other for at least part.

There is much to be discovered. We have yet to discover , for instance, whether there really was a secret communication from Jasper to Raeder, known to some here, or whether it's existence is part of a poorly conceived joke. It is revealing that there exists

I wish you a good luck on finding the other document ( Prinz Eugen B. Nr. G 2243 of 12.7.1941- only sent to the Commander of Cruisers )

Not being a former serviceman, like some here, I find it peculiar that a Head of Department would send a detailed gunnery report direct to the Commander of Cruisers, apparently bypassing my Commanding Officer. This implies dissatisfaction with Brinkmann's description of events not only with his superiors but also his subordinates. Perhaps someone with direct naval experience could comment?

All the best

wadinga

[Alberto Virtuani]

Hello everybody,

a very interesting discussion about navigational vs gun ranges, however, as they can differ by around 350 meters only at 6:00 (shell flight time around 24 secs and relative speed around 30 knots), the "approximation" introduced will be well within the accepted tolerances and can be lightly ignored for the time being.

IMO, in addition to 6:00 as "starting point" (as proposed by Antonio), I think that the approach to reconstruct the British course from the PoW maps and the German course from the PG battlemap is the only logical one.


However the problem I still see in the discussion here, is that someone is very reluctant to accept these starting assumptions (avoiding carefully to propose any credible alternative ones...), being well conscious that, once accepted, they will get unavoidably to the already available 2005 reconstruction of this battle, without much space for refinements, at least until 6:05...


Bye, Alberto

[Antonio Bonomi]

Hello everybody,

well, I think we are making some progresses here, so lets continue on this path waiting for the consensus to come one way or the other.

It is not so important how long it will take, since I had on last 13 years all type of consensus one could have expected, even more than expected sometimes.

Anyway, lets recap and provide some more food for thought from my side.

First I think we need to agree about the fact that talking about bearings and distances, ... the difference between navigational range and gun range in this case will be, ... given speed, course and relative distances, ... in the range of 0,5 degrees, … so well below the +/- 1 degree tolerance as far as the bearing goes, … and below the 1.000 yards every 10 sea miles for the distances, … so inside the tolerances I was proposing and that seems to be acceptable as far as I have read above.

Comments and an agreement about the tolerances I think are needed at this point.

Brinkmann/Reimann occurrence versus Schmundt is an argument to be evaluated aside, when new evidence will be available.

The PoW track and turn shape avoiding the Hood wreckage must be the one drew on the British maps for this exercise.


@ Alberto Virtuani,

there is no other solution in alternative of my 2005 work, simply because given the evidence we have available it is the only possible solution.

Winklareth in order to invent his solution had to avoid to use all the evidence and to reverse the photos, and still his solution was not possible once challenged with some of the evidence available he avoided to mention and use.

Is it possible to improve my 2005 work ? YES of course, but not to change it completely as a basic frame.

The areas were is possible to improve it are the turns shape on both sides, and in this regard I liked very much Herr Nillson proposal about PoW track, ... and on the Bismarck track after the second turn at 06:06 until cease fire at 06:09 ( this thread subject ), … and after, ... until 06:30 when the German squadron went again on a stable course 220°, ... as usual.

The Norfolk and Suffolk correct positions and run tracks are done already and just need to be applied changing the ones my 2005 map on my future work.

Bye Antonio

[Bill Jurens]

I don't think there is yet a full appreciation of the potential differences between gun range and navigational range. The corrections referred to so far seem to revolve around adjustments for target movements during time of flight. While important enough in and of themselves, these are not the errors/corrections I am talking about. They represent only one part, and a smaller part at that, of the total problem.

The other part of the problem revolves around the corrections required to bring the mean point of impact on the target even if the gun and target are stationary. This involves making corrections for variation from range table nominal conditions for things such as propellant temperature, wind, and gun wear. To attack only one facet of the problem, suppose for example that for whatever reasons a given set of guns has worn somewhat in service, and the propellant lot has aged a bit since proofing. If the range table is calculated for 'new gun' velocity, and the gun is half-worn, as a rough approximation we might expect a loss of about 3% in initial velocity. Propellant aging might reduce this by another factor, let's say -- for illustrative purposes -- that a 2% variation is involved. The gun will therefore be firing at a velocity which is something like 5% under the official range table value.

Assuming, again for illustrative purposes, an initial velocity of 2800 f/s, this would result in an actual initial velocity of 2800 * 0.95= 2660 f/s. For a range of around 25000 yards and a big gun, this factor alone equates to a range difference of about 2100 yards.

Now we must (or at least should) take into account air density. Supposing the range table, etc. has been computed for an air temperature of 18 degrees C and a relative humidity of 50%. This equates to a density of approximately 1.21 kg/m^3. We are, however, firing in a temperature of 8 degrees C with a relative humidity of 100%. In this case the air density would be about 1.25 kg/m^3, i.e. about 3.3% greater. This, again for a typical big gun would equate to a range differential of about 300 yards.

For a variety of reasons, projectile lots tend to have something like another 1% variation in drag, which can – at least for this sort of illustrative example, be considered as equivalent to an equivalent change in air density. This adds in, potentially, another 85 yards or so.

Sometimes these effects – and there are more of them, believe me -- somewhat cancel out. Sometimes they do not. The net effect is that in order to hit a target at a range of (say) 21000 yards, even ignoring movement during the time of flight, etc., one might actually have to set the guns to achieve a range of – let’s just estimate – 22,500 yards or so. The sights are set for 22,500 yards, but the range to fall of shot, i.e. the navigational range, is only 21000.

While terminology and technique vary from time to time and from service to service, the main point to be kept in mind is that if the gunnery officer has to set the guns for a range of 22,500 yards in order to hit a target 21000 yards away, 22,500 yards is the figure that is, at least to him, the effective and practical range to the target rather than the navigational range. Which one he might quote in subsequent correspondence and conversation must be extracted from context.

Unfortunately, the quality of the documents we have to work with, at least at this historical remove, often make these discriminations very difficult to make with any degree of certainty.

Bill Jurens

[Alberto Virtuani]

Hello Mr.Jurens,
thanks for your explanation. I fully understand all the parameters that can affect the actual range of a shell (I would add just the effect of firing a cold or a hot gun to the list), but I don't see how they can affect a map construction when we have the cross-checked ranges from the enemy observations.

As the ranges perfectly match between PoW salvo plot and Jasper gunnery report, once accounted for the distance of Hood and Bismarck from PoW and PG based on reports, photo and film, we can assume the ranges to be navigational ones even if they were initially intended as gun ones and even if they differ by 2 km (that I don't believe anyway). It simply means both Germans and British were using the same convention for ranges and that we can ignore the discrepancy between the two of them.

What I mean is that if the 14000 meters reported by Jasper are actually 16000 for the unfortunate added combination of all parameters, we can anyway build a map with a "conventional" distance of 14000 meters, because McMullen data, once adjusted, provide exactly the same value and all ships are affected by the same parameters. All ships will just fire at a distance less than the navigational one.


We are not much interested in "absolute" values but in relative ship positions. However, when 6 ships will be positioned in a precise way relative each to the other, geometry will bring us the distances as a consequence, within due tolerances, mainly affected by bearings precision that in many case is simply perfect, having the same (reciprocal) bearings from two ships.


Bye, Alberto

[Bill Jurens]

Do we have a set of mutually agreed upon and (at least reasonably similar) simultaneous ranges and bearings that we can begin to work from?

I, for one, find a fair amount of the correspondence here confusing due to references to various sketches and written documents which I can't often immediately identify.

In that regard, would it be useful to have correspondents work together to create a mutually agreed upon list of Exhibits, "A", "B", "C" etc. such as is often done in formal court proceedings. Then, once these were posted, we could all be sure that we were all really -- and quite literally -- "on the same page..." when references were being made.

Bill Jurens.

[Antonio Bonomi]

Hello everybody,

@ Bill Jurens,

I think a set of agreed documents and consequently set of information to refer to is a good idea.

I have used this same approach time ago in this forum to agree about the Norfolk track correct positioning, but with no luck.

Now things are changed, and I hope that it will work here as well as after for the Norfolk and the Suffolk track correct positioning as well, just as it must be.

Here my proposal, with the bearings to be considered at first and the distances only after as a verification step in case they match the whole scenario.

From the British side :

The PoW gunnery plot and report - First bearing and timing, after the distances as verification ( British side vs Germans )
The Rowell map ( Exhibit B ) - PoW own track and timing, bearings at 06:00
The Plot of Norfolk and Suffolk map ( Exhibit A ) - Cross bearing among the all battle field warships ( 6 of them ); no distances
The PoW Plan 4 map ( Battle Summary Nr 5 ) - PoW own track and bearings
Ltnt Anthony Hunter-Terry Hood First Inquiry witness interrogation - British side event best timings according to the board
Capt J.C. Leach battle report - British squadron events, timing and relative positioning,

From the German side :

The Prinz Eugen official battle map - Own track and timings plus bearings; no distances toward the enemy
The Prinz Eugen Torpedo map ( Ltnt S. Reimann ) - Own track, timings and bearings; no distances toward the enemy
The Prinz Eugen Ltnt Paulus Jasper gunnery report - Own battle timings and distances as verification ( German side vs British )
The Prinz Eugen Ltnt Paul Schmalenbach gunnery report - Battle timing and German squadron event description
Prinz Eugen im estern gefecht ( F.O. Busch 1943 book ) - German squadron relative positioning and early battle stage bearings
Adm Lutjens radio messages - Battle events and main timings, after the distances as verification

As you can see the main course are the bearings and the event timings.
Only after the distances as second priority to be used only as verification check when they match.

Bye Antonio

[Bill Jurens]

This would seem to be a good start. Does any other correspondent wish to either add a document or for whatever reasons -- which should be specified -- have one of these documents removed?

Bill Jurens

[dunmunro]

This would seem to be a good start. Does any other correspondent wish to either add a document or for whatever reasons -- which should be specified -- have one of these documents removed?

Bill Jurens

Yes:
http://www.hmshood.org.uk/reference/off ... 09suff.htm

and Leach's narrative and W-W's narrative for RN and KM open fire times and:

http://www.hmshood.org.uk/reference/off ... 9to144.htm

which supports Bismarck opening fire well before 0555.