Bismarck firing procedures at DS

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Alberto Virtuani
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Re: Bismarck firing procedures at DS

Postby Alberto Virtuani » Sat Jun 25, 2016 9:35 pm

Alecsandros wrote:"...Jaspers mentions an average rate of fire over the entire length of the battle time...."

Hi Alec,
PG average RoF was 37,5 secs (1,60 rpmpg) over the 14 minutes battle.
Jasper says that "the heavy artillery attained a salvo rate of fire of 27-28 seconds", so this seems to be the max RoF during the battle.

you wrote: "I also think the final part of the battle (6:04 - 6:09) was done at a lower rate of fire....."

This is only possible if the fore turrets were not wooded. In case the turrets were wooded after salvo 28 against PoW (count of ordered shots is now 48 initial "ranging"" + 96 during the "rapid fire" from 5:59:30 till 6:04:30) PG had to fire 36 shots in 4 minutes and half, thus the RoF (with just 2 turrets bearing) is still 27/28 seconds.
Only in case the fore turrets were still firing when on course 270°, then we can assume Albrecht slowed down the RoF, but this is not what Jasper said: "...Albrecht continued to fire rapid partial-salvos...."


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Re: Bismarck firing procedures at DS

Postby alecsandros » Sun Jun 26, 2016 6:56 am

Alberto Virtuani wrote:PG had to fire 36 shots in 4 minutes and half, thus the RoF (with just 2 turrets bearing) is still 27/28 seconds.

... 4 aft guns x 4,5 minutes x 1.5 spmpg = 27 shots.
... 4 aft guns x 4,5 minutes x 2 spmpg = 36 shots.

IF Prinz Eugen ordered (only) 48 shots in the first 4 - 4.5 minutes of the battle, and only fired from her aft turrets for the most part of the disengagement (final) phase, then the rate of fire over the critical 5:59 - 6:04 interval must have been at least 2,5 spmpg ... Otherwise there wouldn't be enough time to order 184 shots.

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Re: Bismarck firing procedures at DS

Postby alecsandros » Sun Jun 26, 2016 7:09 am

Another aspect from Jasper: he says the opponent turned hard towards us at around salvo8 (PoW 6:00:30 or 6:01). He also says forward turret group not training on target at around salvo 28 (6:04).

So, the magic number becomes 20 salvos, fired between "opponent turned hard " and "fw group not training".

In any case, 20 salvos in 3 minutes, of which many must have been full salvos, implies a higher rate of fire then the 27-28 seconds average.

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Re: Bismarck firing procedures at DS

Postby Alberto Virtuani » Sun Jun 26, 2016 7:47 am

Hi Alec,
your analysis is correct and I agree that there could have been a slight increase of the RoF when in fore direction rapid fire mode.

However we know (from PoW plot) that PoW "turn" (heeling should be the correct definition) toward PG happened just after 6:00:10. From 6:00:40 till 6:01:30 the ship was again on 280° course and at 6:01:30 the ship started the 160° turn to port.

PG turn starts (according to his own plot) at 6:04, therefore the turrets could be wooded only at around 6:04:30. The 96 shots (12 full salvos) can be fired from, let's say 6:00:20 till 6:04:40 (assuming the salvo 5 after the ranging procedure against PoW was fired by A+B turrets, while salvo 28 by C+D, allowing still Jasper to fire them before transferring control) with a RoF of 27 seconds, as Jasper says.

Assuming 5 or 10 seconds lost due to change of direction to Albrecht and to reload C+D turrets just fired at 6:04:40, you see that the RoF when in aft control was very close to the 27/28 seconds.

So both our hypothesis are possible, but in both cases the max RoF cannot be much less than 23 / 25 seconds. However I think that Jasper would have mentioned such a RoF in his report, so I still have a preference for the "metronomic" firing as this is what we can deduce from Jasper account.


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Re: Bismarck firing procedures at DS

Postby alecsandros » Sun Jun 26, 2016 9:22 am

... I agree it is possible that PE fired as you say, with a peak of 27-28 seconds.

As far as I know so far, the timing of the battle is in a little gray area, as German and British timings were almost certainly not in perfect synchronisation. If Prinz Eugen's turn starts at 6:04 on her plot, it is not necessarily correct that Prince of Wales's turn around Hood started at 6:00:10 on Prinz Eugen's time sheet. Remember Jaspers says 6:01 as time of destruction of Hood. Prince of Wales turn started at around 6:03 based on her own map... And we know practically all accounts agree on the matter that the 2 forces disengaged at almost exactly the same moment...

Thus my intuition is that the interval described in Jaspers account (between 8th salvo - opponent turning towards us - and 28th salvo - fw turrets not bearing on enemy) is no larger then 3 minutes maximum. If so (and I have no degree of probability - I don't know how in or out of sync the watches were, and by how many seconds), 20 salvos per 3 minutes means 6.66 salvos/minute, or 26 shots / minute (if considering ONLY semi-salvos numbered in Jaspers' account).

In other words I would like to describe the following possibility: Prince of Wales time: hard turn started at around 6:00:30, disengagement turn under smoke started at around 6:03:00, final salvos fired by the Germans through the smoke screen at around 6:08.
Prinz Eugen time: hard turn of enemy at around 6:01:20, torpedo alarm at around 6:04:30, final salvos fired against the enemy through the smoke at around 6:09.

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Re: Bismarck firing procedures at DS

Postby Alberto Virtuani » Sun Jun 26, 2016 9:35 pm

Hi Alec,
I do see your points.
Re timing, however, I remember someone, in the beginning of the mega-thread on DS and RN articles of war, mentioned that even during WWII, the chronometers on board the ships were extremely precise, suffering of a very small error per day when at sea .
I don't remember the exact figures, but I remember that for ships at sea since few days (like Hood and PoW) the difference between the 2 clocks could not exceed 2 to 3 seconds....
Between German and British ships (German ships were at sea since few days as well) the difference could have been of 10 to 20 seconds, due to a slighly different initial reference.
All the discrepancies in timing are due basically to human errors in writing down the exact moment of the facts or to delays doing so.


So said, we have also photos, prints and the film synchronizing the timings between the 2 divisions, the most clear sync timing being the 6:03:45 that Antonio Bonomi has demonstrated with his research work still in 2010 (see below):

06_03_45 seconds of DS battle_red.jpg
06_03_45 seconds of DS battle_red.jpg (104.78 KiB) Viewed 269 times

This is why I would still keep with the timeline we have for long time discussed.


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Re: Bismarck firing procedures at DS

Postby alecsandros » Mon Jun 27, 2016 5:53 am

... Alberto,
The difference in recordings is much greater then 10/20 seconds, usualy ordering around 1 minute between British and German recordings, allthough, on occasion, they are much bigger (3 minutes or more).

I agree the exact time displayed on clocks on both forces could have been much more similar then the recordings might suggest. However, we work with what we have. Prince of Wales maps shows Hood destroyed at 6:00; Prinz Eugen maps show 6:01. Retreat time for Prince of Wales under smoke is around 6:03 on her own maps, and 6:04 on Prinz Eugen maps.

As this discussion has been much longer in the past, I would rememorise the conclusion that Prince of Wales withdrew immediately after Hood was destroyed, the only limit being the arc necessarily described around the sinking battlecruiser. The duration of time required to follow said arc couldn;t have been longer then 2 , maybe 3 minutes maximum.
---
On the other hand, (and against my above assumption) it is possible that Prinz Eugen's forward battery was still on target after the torpedo alarm has been sounded, and was "not bearing" at another moment in time, perhaps 1 minute or even more from the start of the torpedo alarm. [allthough I would expect fire to be made at a different, slower pace, as the target was almost certainly lost during the hard turn]

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Re: Bismarck firing procedures at DS

Postby Alberto Virtuani » Mon Jun 27, 2016 7:22 am

Alecsandros wrote: "it is possible that Prinz Eugen's forward battery was still on target after the torpedo alarm "

Hi Alec,
you are right and I was thinking the same, as in theory the angle was close to the limit one for PG, but not clearly over it (especially if you look at PG battle map).
However, Jasper says that Albrecht continued to fire rapid partial salvos, and this is clearly not possible if the 4 turrets were all bearing after 6:04 , having to fire only 20 shots..... :think:

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Re: Bismarck firing procedures at DS

Postby alecsandros » Mon Jun 27, 2016 7:30 am

Alberto,
I don't know why 20 shots ? Could you please elaborate, as I don't remember this number (excuse me if it was discussed above, I don;t remember, I am a bit tired... )

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Re: Bismarck firing procedures at DS

Postby Alberto Virtuani » Mon Jun 27, 2016 8:42 am

Hi Alec,
no, you are right, my mistake, you are right...... :oops: , 40 shots.

5 "ranging" salvos to Hood (2 Vollsalve + 3 semisalvos in Gabellgruppe) = 28 shots (fired at battle time 5:55:xx - 5:57:xx)
4 "ranging salvos to PoW (1 Voillsalve + Gabellgruppe) = 20 shots (5:58::xx - 5:59:xx)
24 rapid salvos to PoW (semi-salvos) up to salvo 28 (to PoW) = 96 shots (5:59:xx - 6:04:40 assuming salvo 5 is A+B and 28 is C+D)

The remaining 40 shots to get to 184 (ordered) are the ones fired by Albrecht in aft control with C and D from 6:05:xx till 6:09:xx with almost the same RoF of 27-28 secs.

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Re: Bismarck firing procedures at DS

Postby alecsandros » Mon Jun 27, 2016 8:57 am

I see now.

Do we know how Jaspers counted the salvos ?

For example, the Gabellgrupen (3 semisalvos) was counted as 3 salvos, 1 salvo or 2 salvos (1 full and 1 partial) ?

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Re: Bismarck firing procedures at DS

Postby Alberto Virtuani » Mon Jun 27, 2016 9:23 am

Ciao Alec,
I have used the definition that Marc has kindly provided at pag 26 of this thread (my bold/underlined):
Herr Nilsson wrote:"If Jasper uses the word salvo it relates to the salvo record and does not say anything about the salvo itself. A certain salvo from this salvo record can be a full salvo, a partial (semi) salvo or a turret salvo. The distinguishing feature between salvos aren't the number of guns, but the setting values of the salvos. New values (including time), new salvo."

Thus I have counted just the salvos, without distinguishing between full and semi-salvos (or turret as it could hypothetically have been for Albrecht when in aft control....). Volsalve = 1 salvo, Gabellgruppe = 3 salvos, just 1 turret firing = 1 salvo, etc.

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Re: Bismarck firing procedures at DS

Postby alecsandros » Mon Jun 27, 2016 9:35 am

If I read the text correctly,
If a Vollsalve was fired at slighly different time intervals (semisalvo1 at t0 and semisalvo2 at t0+5 seconds) , it could count as 2 salvos ?

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Re: Bismarck firing procedures at DS

Postby Herr Nilsson » Mon Jun 27, 2016 9:55 am

Does a salvo with the same setting values 5 seconds later make sense?

Anyway, that's how a artillery officer log sheet looks like:

Image
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Re: Bismarck firing procedures at DS

Postby alecsandros » Mon Jun 27, 2016 10:41 am

Herr Nilsson wrote:Does a salvo with the same setting values 5 seconds later make sense?

It depends. If one fires the initial salvo on purpose 400m short, and wants to straddle, he could fire the second salvo at a slight interval with the same settings, and possibly be correct, by straddling the target between the 2 semi-salvos.


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