Bismarck at DS after the second turn

[Alberto Virtuani]

Hello everybody,

I wrote: "PoW was already some 200 meters on HOOD starboard side"

Having redone a more precise calculation, I have to correct my approx statement above.

Pow was stationed at 4 cables (= 740 meters, the dotted line in Antonio's proposed "starting point" at 6:00 from Rowell map download/file.php?id=3311) from Hood.
At the same time, the angle between Hood-PoW and their course (280°) is 25°, thus PoW was already some 310 meters on Hood starboard side (distance in orange).

Map_1cm_1000meters_scale_detail.jpg (21.39 KiB) Viewed 1823 times

Bye, Alberto

[wadinga]

Hello All,

Once again, as with the openness or otherwise of A arcs we have an attempt at analysis based solely on Rowell's questionable plan, to try and disprove what numerous witnesses saw or did in reality. We have already established Official Tracks are in error, and even Antonio has accepted this

I agree with Wadinga statements about the PoW maps and tracks to be deeply analyzed for some turns inconsistencies,.

Leach: Course had to be altered to starboard to avoid remains of "Hood";

Jasper: At about the 8th salvo the opponent turned at first hard towards us

Reimann "The turning towards us by the opponent was first observed by the observation tower and shortly thereafter verified by the bearing taker in the computing station.

Brooke Another salvo had just gone when I heard Guns warn his director layer 'Stand by to alter course to port'. This long-awaited move— presumably we were going back to the original heading so that 'Y' turret could bear for the first time—had begun to take place, in that we heeled to starboard and it became temporarily more difficult to hold the Bismarck steady in one's glasses, when the ship suddenly rolled upright again and then continued to heel over the opposite way; moreover, with the urgency and excessive vibration that comes only from violent rudder movement. We were going hard-a-starboard. Back towards the enemy again. What the hell was going on? There was a momentary lull. Probably the director gunner had been put off his aim, and in the comparative quiet I realised that hitherto there had been an intermittent background noise. The ship steadied up and there began to come back to port. Dick Beckworth said "my god! The Hood's gone!...

And Busch as well.


These witnesses all confirm each other and confirm the Rowell plans drawn in August do not correctly show PoW's course. Therefore precise analysis based on incorrect information serves no purpose.


The PG timing for first British salvoes is significant and suggests the salvo plan timings are close to common chronometer time. This is proper valid research- we need more of it.


All the best

wadinga

[northcape]

Hello everybody,

I wrote: "PoW was already some 200 meters on HOOD starboard side"

Having redone a more precise calculation, I have to correct my approx statement above.

Pow was stationed at 4 cables (= 740 meters, the dotted line in Antonio's proposed "starting point" at 6:00 from Rowell map download/file.php?id=3311) from Hood.
At the same time, the angle between Hood-PoW and their course (280°) is 25°, thus PoW was already some 310 meters on Hood starboard side (distance in orange).


Map_1cm_1000meters_scale_detail.jpg



Bye, Alberto

I'm sorry but to believe that this (or any other original map/sketch) from the DS battle can be used to derive distances with accuracy in the range of 10s or even few 100 meters is more than pure speculation (same accounts for bearings).
You have to consider (1) the accuracy of the original data (approx. bearings and approx. speeds at sparse intervals) - this is not a GPS track!
(2) Even if you would have GPS way pints, this is a hand-drawn sketch for the purpose to give a general impression of the battle. You are not measuring a true distance just because you put a ruler on a piece of paper. You have to think about how those track lines on the paper were created, and how they can differ from the true (unknown) tracks.

[Antonio Bonomi]

Hello everybody,

we can all look at the details and minor changes on the available reference base maps after having reached a base agreement.

I do not care at the moment about the small turn changes or the minor inconsistencies reshaping the main tracks on the base reference map.

I renew my invitation to everybody to clearly express themselves about the proposed reference base map I have attached above.

It is based on Rowell second board map and the Prinz Eugen original tracks made in sync and aligned at 06:00 battle time, with a bearing 143° from Prinz Eugen to PoW as for both Brinkmann and Reimann bearings taken at that time toward the PoW.

It is just made with well known available official documents on both sides, nothing else.

If one agrees, fine, just let us know in writings.

If one does not agree I like to ask the reasons why and what he is proposing as an alternative to the proposed base reference map.

This is the only way to move forward I think.

Thanks for the cooperation.

Bye Antonio

[Alberto Virtuani]

Hello everybody,

northcape wrote: "I'm sorry but to believe that this (or any other original map/sketch) from the DS battle can be used to derive distances with accuracy in the range of 10s or even few 100 meters is more than pure speculation (same accounts for bearings)...You are not measuring a true distance just because you put a ruler on a piece of paper..."

I'm deeply sorry I was not clear enough to allow everybody to understand, when answering to a reasonable consideration from Algonquin-R17.

Nobody here has calculated a distance using a ruler or measuring on any map, I just edited myself the map used by Antonio to visually explain in an easier way what I had already calculated geometrically based on the available official documents.

The distance of PoW track from Hood track can be calculated based on the fact that PoW was stationed (following Holland orders) at 4 cables from Hood on true bearing 75°(this comes from Diagram "A" of the first board http://www.hmshood.org.uk/reference/off ... -4351_to59).
Due to the fact that the angle marked on my detail from Rowell map is therefore 25°at 06:00 (as it was 45° at 05:55 before the 20° turn to open arcs), using basic trigonometry, if the overall distance between the ships (the dotted line in the map) is 740 meters, then PoW was around 310 meters to the right of Hood (orange line): 740 meters * sin(25°) = 313 meters. No map or ruler is involved in the calculation, just geometry.

The above map (viewtopic.php?f=1&t=8335&p=81462#p81458) was used to try to make it clear for everybody's convenience.

Of course we accept that 740 meters can be an approximation and that it was not rigidly 740 all the time, but when sailing in close formation, we cannot imagine very large errors to be tolerated by any admiral (BC1 in this case) and the distances were confirmed during the board...

Antonio Bonomi wrote: "I renew my invitation to everybody to clearly express themselves about the proposed reference base map I have attached above. It is based on Rowell second board map and the Prinz Eugen original tracks made in sync and aligned at 06:00 battle time, with a bearing 143° from Prinz Eugen to PoW as for both Brinkmann and Reimann bearings taken at that time toward the PoW.
It is just made with well known available official documents on both sides, nothing else.
If one agrees, fine, just let us know in writings.
If one does not agree I like to ask the reasons why and what he is proposing as an alternative to the proposed base reference map."

Hi Antonio,
I'm fine with the approach as per your proposal download/file.php?id=3311,
and I do agree with your call to everybody in order either to accept it or to propose any alternative.


Bye, Alberto

[Bill Jurens]

I am glad to see that we seem to be making progress here.

One correspondent suggested that an overlay of the most relevant track charts might be a useful tool in analysis. This is true, and represents in fact, how I have tended to approach the problem, at least initially, in the past.

Unfortunately, tracing the surviving track charts from the British and German sides, calibrating them, reducing them to the same scale, and attempting to superimpose them has, in my experience, led to only the most discouraging results. I have attached a recent example, with British track charts (of both sides) presented in blue, and German track charts (again, of both sides) printed in red. In this particular example, I have used two benchmark locations, one at 0553 and one at 0600 -- marked with prominent "X" markings, and attempted to bring the relative plotted positions of the German sections of the track charts into the best visual alignment, which in and of itself, is not too good. This alignment attempt occurs in the upper left corner, leaving the lower right corner, i.e. the comparative British positions to 'drift'. As is very clear, the relative alignments are not very good at all. They could be markedly improved by shifting either the German positions northwest about 4500 meters or the British positions southeast a similar amount, but that would, of course completely disrupt the initial alignments taken as a beginning point in the upper left corner.

TRACK CHART SAMPLE.jpg

(115.95 KiB) Not downloaded yet

Comments very welcome...

Bill Jurens

[Alberto Virtuani]

Hi Mr.Jurens,
thanks for posting this interesting chart that very evidently shows how difficult would be to try to reconcile all the existing tracks (not to speak about witnesses and accounts).


However, I had understood that you had agreed on Antonio's approach to use British tracks for the British ships and German tracks for PG (see: viewtopic.php?f=1&t=8329&p=81141&hilit= ... nts#p81141). More specifically, Rowell map for PoW movements and PG battlemap for PG movements.

Am I missing something ? Why are we still trying now to reconcile also the German tracks for British ships (that are evidently wrong, because, apparently, the PG officers totally misunderstood the tactical situation that day, separating Hood and PoW while believing PoW was coming together with Norfolk) and the gross estimation of the Bismarck track done by McMullen through the interpretation of the PoW salvo plot and fall of shells observations (wrong as well, even if much much less blatantly wrong than the first one) ?


Bye, Alberto

[Byron Angel]

I am glad to see that we seem to be making progress here.

One correspondent suggested that an overlay of the most relevant track charts might be a useful tool in analysis. This is true, and represents in fact, how I have tended to approach the problem, at least initially, in the past.

Unfortunately, tracing the surviving track charts from the British and German sides, calibrating them, reducing them to the same scale, and attempting to superimpose them has, in my experience, led to only the most discouraging results. I have attached a recent example, with British track charts (of both sides) presented in blue, and German track charts (again, of both sides) printed in red. In this particular example, I have used two benchmark locations, one at 0553 and one at 0600 -- marked with prominent "X" markings, and attempted to bring the relative plotted positions of the German sections of the track charts into the best visual alignment, which in and of itself, is not too good. This alignment attempt occurs in the upper left corner, leaving the lower right corner, i.e. the comparative British positions to 'drift'. As is very clear, the relative alignments are not very good at all. They could be markedly improved by shifting either the German positions northwest about 4500 meters or the British positions southeast a similar amount, but that would, of course completely disrupt the initial alignments taken as a beginning point in the upper left corner.

TRACK CHART SAMPLE.jpg

Comments very welcome...

Bill Jurens

- - -

The portrayal of the Hood/PoW track as possessing a gentle curvature to port does nicely address the issue of PoW's Y turret "wooding". Based upon the McMullen PoW salvo plot, with its assumed steady course of 280deg throughout the period from 0555 up to 0600 hrs and the recorded target bearings over that span of time, it is impossible to make any geometrical sense as to how Y turret could have been "wooded" up until 0557:30 and able to bear thereafter.

B

[Byron Angel]

Re the nature of PoW's evasive turn away from the wreckage of Hood -

Based upon the performance details of HMS Hood and HMS Repulse under helm at high speed, it might be possible to draw some b r o a d inferences with regard to PoW's sudden starboard turn to avoid the wreckage of Hood

Notes -
> Hood, Repulse and PoW were all of four screw, single rudder design.
Hood - 860ft Length x 104ft Beam
Repulse - 750ft Length (p/p) x 90ft Beam
PoW - 740ft Length (w/l) x 103ft Beam
... Above dimensions approximate.

HMS HOOD
31 knots @ 15 degrees helm turns through 45 degrees in 86 seconds.
31 knots @ 35 degrees helm turns through 45 degrees in 55 seconds.

HMS REPULSE
30 knots @ 35 degrees helm turns through 45 degrees in 48 seconds.

Inferences that might be drawn -

[ 1 ] If the differential in rate of turn of HMS Repulse at 15 degrees helm versus 35 degree helm is similar to that of Hood, then HMS Repulse at 30 knots and 15 degrees helm might be expected to turn through 45 degrees in approximately [86/55] x 48 = 75 seconds (1.67 seconds per degree).

[ 2 ] If the average rate of turn through the first 45 degrees at 15 degrees helm = 1.67 seconds per degree and the average rate of turn from 45 through 90 degrees = ~1 second per degree (trust me on this), then the initial rate of turn at the moment the helm was first put over would arguably have been somewhere in the vicinity of 2.33 seconds per degree.

[ 3 ] If PoW was making 28 knots at an interval of ~800 yards from Hood fine on her port bow, she would have had a maximum of ~50 seconds to undertake avoiding action from the moment in time when Hood was seen to have been stricken and veering to starboard.

[ 4 ] At 15 degrees helm, PoW could have reasonably been estimated to have altered her heading by [50 seconds / 2 seconds per degree] about two points (22.5 degrees) and, at 35 degrees emergency helm, by up to about three points 33.75 degrees).

[ 5 ] With respect to diminishing the possible number of degrees of course alteration to allow for delay in transmission of the order to the helmsman, I leave to those with more up to date crystal balls.

FWIW.

B

[Antonio Bonomi]

Hello everybody,

@ Bill Jurens,

I see your trial above and of course done in the way you did it can only show that without a common agreed reference mark is not possible to merge and reconcile the 2 available maps.

That was more than obvious using only the original map distances and the timing reported on the original maps.

But this is simply the reason why I have used the Rowell map as a base and I have positioned the Prinz Eugen track based on known bearing between the Prinz Eugen and the PoW ( 143 ° ) available on 2 German tracks ( original map and Torpedo map ) and used the Jasper distance from his report ( 15.000 meters at 06:00 ) that was surely very close to the reality since he was scoring hits on PoW on that moment and immediately after until 06:03 ( until the distance went down to 14.000 meters ).

I thought that it was clear to everybody that without that 06:00 common agreed reference mark it was not possible differently to align the Prinz Eugen track and the PoW map made by Rowell for the second board showing the situation at 06:00.

The common reference mark is 143° bearing between Prinz Eugen and PoW and 15.000 meters distance between them, both at 06:00.
Only with this reference mark it is possible to merge the 2 maps together.

I thought I made it clear on my previous post here :

viewtopic.php?f=1&t=8335&start=135#p81452

I did explain before why 15.000 meters was correct at 06:00, and why the PG map and her torpedo map had incorrect distances on them.

I hope that now everybody can check the official documents, I mean the Jasper report for the 15.000 meters distance between PG and PoW at 06:00 and the 2 PG maps for the 143° bearings and agree about this being the most accurate estimate we can make between the 2 warships, PG and PoW at a given time, I mean at 06:00.

After having done this check, I hope everybody will agree that using this common reference mark ( 143° bearing and 15.000 meters between PG and PoW at 06:00 ) we can put together the 2 tracks ( PG and PoW ) as I did on my example here above yesterday.

If we will do this and agree about it we will have our reference base map to start working with.

If I have been too fast and did not provide enough detailed explanations on what I did and why I did it, I beg you pardon.

Hope now all should be more clear to everybody and easy to be double checked and understood, accepted and agreed among us all.

Of course if somebody does have a better idea on how to merge those 2 maps using a reliable common bearing and distance at a given time, please bring it forward and we can discuss it.

The advantage of my method is that we have right away the 4 main warships tracks almost perfectly available at once, because the Bismarck is almost done just referencing the PoW and the PG tracks, ... and after by using the PoW gunnery plot bearings now.

It is very easy to do it this way.

Opinions welcome.

Bye Antonio

[wadinga]

Hello Bill,

Thank you for showing your track chart example.

They could be markedly improved by shifting either the German positions northwest about 4500 meters or the British positions southeast a similar amount,

This shift is remarkably similar to the 4100m consistent error in much the same orientation identified (by Antonio) as the error between the values Brinkmann and Reimann both recorded and that which Jasper had for 06:00. I have speculated that although Jasper was getting correct range values a electrical transmission fault gave both Reimann and Brinkmann artificially high values consistently offset from the real value by 4100m. Can you shift the German plots of PoW's tracks 4100m along 323 degrees?

All the best

wadinga

[Alberto Virtuani]

Hello everybody,

thanks to Byron Angel for the above posted turning data for British ships.

However, the turn to avoid Hood wreckage was anyway irrelevant in terms of course alteration:
at open fire, on course 300°, bearing was 335° and it was an impossible one for Y turret that had 45° blind angle fore on each side. On course 280° bearing 335° was possible by only 10° but the bearing was slowly diminishing during the battle due to the geometry of the approach, at 6:00 PoW was firing at Bismarck her guns (including Y turret) at a true bearing 330°-329°. Thus at 6:00 the turret was almost wooded again (5° margin only, that explains Holland decision for a further turn, the one never executed).

The "avoiding" maneuver cannot have been but a simple hard turn of the helm to starboard and few seconds later a hard counter-turn (perfectly logical as PoW was already around 300 meters to the right of Hood and did not strictly need to turn away from the wreckage). Such a "maneuver" would have made PoW rolling violently (full speed + full rudder), but actually changing course by 5°- 10° only (as per Rowell map, but less emphasized), not even wooding Y turret for more than 20 seconds, as the RoF was one salvo every 20 seconds at that point in time and Y turret lost no shot at all, as proven by the PoW GAR (see viewtopic.php?f=1&t=8335&start=135#p81455).

Therefore the "avoiding maneuver" was actually just a rolling movement, with a minimum course change that is not even depicted in the PoW salvo plot.

Byron Angel wrote: "The portrayal of the Hood/PoW track as possessing a gentle curvature to port does nicely address the issue of PoW's Y turret "wooding". Based upon the McMullen PoW salvo plot, with its assumed steady course of 280deg throughout the period from 0555 up to 0600 hrs and the recorded target bearings over that span of time, it is impossible to make any geometrical sense as to how Y turret could have been "wooded" up until 0557:30 and able to bear thereafter."

It maybe addresses the above "issue" but it's a "curvature" imagined by PG officers who were totally unable to tactically read the situation that day and who even imagined that PoW ("King George" in the map) was coming from North, together with Norfolk (see PG map detail here below), instead of coming from South together with Hood.

PG_map_detail.jpg (54.73 KiB) Viewed 1591 times

The fact that PoW was on course 280° from 05:38, then on course 300° from 05:50, then back on 280° from 5:55 is on her map (http://www.hmshood.com/history/denmarks ... Wtrack.jpg) and all her turns "by blue pendant" are clearly described in Leach narrative (attached to Tovey despatches), matching perfectly with the PoW map. The turns may have been executed very smoothly instead of the depicted angles, but the course is well defined and not questionable.

The "issue" why, after having turned 20° to port to 280°, the Y turret did not fire immediately at 05:55, opening fire only after 05:57 has been discussed and several answers are possible: 1) the map is slightly wrong, depicting the turn at 05:55 when it was ordered at 05:55 and actually executed only at 05:57; 2) the turn execution was started at 05:55 but in such a slow way (resulting in a "gentle curvature" as per PG map) that it took almost two minutes to open arcs, in order not to disrupt gunnery with a hard turn; 3) due to the proximity of the aft superstructure to the Y turret, fire was not open immediately, at high elevation, to avoid damages to personnel/material while the fore turret were still looking for the range. Only when elevation was lower, fire was opened, still on extreme fore bearing, as range had just been acquired and maximum output was required, despite possible self-inflicted damages.

For sure the solution is not in trying to use the PG track for the British ships in reconstructing the battle, because it is totally wrong and "useless" in this regard.



@all:
I still see neither anyone willing to accept the Antonio's proposal for the 06:00 starting point" to reconstruct the battle and try to draw a battlemap (download/file.php?id=3311), nor an alternative one...



Bye, Alberto

[northcape]

I might comment that one thing must not be forgotten: Any sudden change of course at high speed will throw off the gyrocompass - so the bearings (if any) taken after initiation of the hard turns should be taken very cautiously, or at least they should be assumed to be much more inaccurate then the bearings prior to the battle.

[Byron Angel]

I have re-visited the A arc question and discovered a logic error on my part, which I attribute to the late hour and an excessive intake of Bailey's Irish Cream. Based upon McMullen's diagram and recorded bearings, Bismarck would have been with PoW's A arc on any compass bearing =/> 325 degrees.

B

[wadinga]

Hello All,

The "avoiding" maneuver cannot have been but a simple hard turn of the helm to starboard and few seconds later a hard counter-turn (perfectly logical as PoW was already around 300 meters to the right of Hood and did not strictly need to turn away from the wreckage)

with a minimum course change that is not even depicted in the PoW salvo plot

Only because the plot is crude, inaccurate and wrong.

Leach: Course had to be altered to starboard to avoid remains of "Hood";

Jasper: At about the 8th salvo the opponent turned at first hard towards us

Reimann "The turning towards us by the opponent was first observed by the observation tower and shortly thereafter verified by the bearing taker in the computing station.

Brooke Another salvo had just gone when I heard Guns warn his director layer 'Stand by to alter course to port'. This long-awaited move— presumably we were going back to the original heading so that 'Y' turret could bear for the first time—had begun to take place, in that we heeled to starboard and it became temporarily more difficult to hold the Bismarck steady in one's glasses, when the ship suddenly rolled upright again and then continued to heel over the opposite way; moreover, with the urgency and excessive vibration that comes only from violent rudder movement. We were going hard-a-starboard. Back towards the enemy again. What the hell was going on? There was a momentary lull. Probably the director gunner had been put off his aim, and in the comparative quiet I realised that hitherto there had been an intermittent background noise. The ship steadied up and there began to come back to port. Dick Beckworth said "my god! The Hood's gone!...

And Busch as well.

Oh yes let's add

Brinkmann "At the time when the Prince of Wales turned hard towards the German formation between 05:01 and 05:02 hours I estimated that an opportunity for a torpedo launch had arrived.

Once again an attempt to overturn overwhelming evidence from people who were there with an individual's opinion based on what? Intuition? The Rowell map is crude and inaccurate because it leaves out features experienced by those aboard PoW and seen by those aboard Prinz Eugen.


Byron, notwithstanding the Bailey's...……... witnesses say the A arcs remained closed. Theories are fine but evidence is based on what actually happened, not what we might assume should have happened.

All the best

wadinga