Bismarck firing procedures at DS

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Antonio Bonomi
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Re: Bismarck firing procedures at DS

Post by Antonio Bonomi » Mon Feb 22, 2016 7:44 am

Hello everybody,

@ Alberto Virtuani,

many thanks Alberto for your nice compliments :oops:

You correctly wrote :
However, IMHO, due to the fact that PoW salvo 20 was fired by one of the same guns that fired salvo 19 (Y1 or Y4), and that this salvo landed at 6:03:25, as per photo NH69731, I would not assume PoW salvo 20 could land before 6:03:55 (giving at least 30 seconds to reload the same gun as per theoretical RoF of British 14"). What do you think ? Does this match with the other evidences ?


Based on the above assumption of 30 seconds being the minimum reload time ( rate 2 shells each minute ) for the PoW guns ( Y1 or Y4 in this case ) we can move the PoW salvo 19th showed on photo Nh 69731 being fired at 06.03 and 00 seconds from the previous 06.03 and 10 seconds I was calculating before.

I obtained the previous time by subtracting 20 seconds from the salvo 20th that is the milestone reference being fired at 06.03 and 25 seconds, because 20 seconds is the time between salvo 20th and 21st, .... as we can see on the PG film, ... but now it is clear that it was not the real PoW guns reloading time since the gun that fired salvo 21st was another one not firing on salvo 20th, ... the Y3.

The salvo 20th from PoW landing at 06.03 and 45 seconds is the base reference in synch with PG battle map showing the Prinz Eugen first turn.

This movement of salvo 19th of 2 guns departing from PoW at 06:03:00 is perfectly in line with PoW gunnery plot map, which shows the Y turret local control salvos being fired starting at 06:03:00 exactly, ... and everybody can check the X they traced there.

I like to underline that the photo Nh 69731 not only shows the PoW salvo 19th Landing at 06:03:15 after 15 seconds flight time, ... but it shows also the Bismarck salvo 16th landing on PoW on the same moment, ... so we can assume Bismarck salvo 16th being fired at 06:03:00 and landing on PoW at 06:03 and 15 seconds as well.

PoW salvo 19th and Bismarck salvo 16th are in synch and have been fired almost simoultaneously.

But if Bismarck salvo 16th was fired at 06:03:00 ... and the salvo 17th we can see at the beginning of the PG film was fired at 06:03:29 seconds ... we have an interval of 29 seconds between the 2 salvos ... enough to make the turn of 50 degrees to starboard from course 220 to course 270 ... all seems to match well ... :think:

Hope all is clear ... and thanks for the value add input. This is exactly what I am looking for to improve my work ... :wink:

Bye Antonio :D
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Re: Bismarck firing procedures at DS

Post by alecsandros » Mon Feb 22, 2016 8:13 am

@Antonio

Very nice work...

But very approximate my friend... I see you kept semi-salvo 11 on Hood and semi-salvo 12 on Prince of Wales...

I personally have doubts over the entire firing cycle of Bismarck... and also on her ammo consumption...

But with the quality of the info available... It's probably the best reconciliation of the facts...

Best,

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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Mon Feb 22, 2016 8:48 am

Alecsandros wrote: "I see you kept semi-salvo 11 on Hood and semi-salvo 12 on Prince of Wales... "
Hi Alec,
I understand your doubts but I don't see any way in which BS could have fired a salvo (no. 10) hitting (and sinking) Hood at 6:00 (some seconds before the catastrophic deflagration), fired other 2 salvos (11 and 12) at Hood expected position, then switched (even if quickly) fire to PoW and finally fired a first salvo (13) hitting the compass platform at 6:00:50.....

It does not match with the BS RoF up to that very moment, and film frame (see below) clearly show PoW with BS shells splashes around already when PoW had not yet reached the Hood remains position, therefore less than 1 minute after the fatal hit (PoW is sailing 800 meters behind Hood, at 29 knots she covers more or less 800 meters in one minute). :think:
PoW_compass_hit_BS (2).jpg
PoW_compass_hit_BS (2).jpg (27.51 KiB) Viewed 1773 times
I think the salvo in the film frame is no. 12 (if not even no.11, in case Schneider was still waiting the fall of shots before firing the next salvo, despite the "rapid fire" order.....).

In any case we speak about a couple salvos that are doubtful because I guess all the others are covered by film/photos and can be "easily" timed by Antonio..... :D

Bye, Alberto
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Re: Bismarck firing procedures at DS

Post by alecsandros » Mon Feb 22, 2016 9:32 am

Alberto Virtuani wrote:
I understand your doubts but I don't see any way in which BS could have fired a salvo (no. 10) hitting (and sinking) Hood at 6:00 (some seconds before the catastrophic deflagration), fired other 2 salvos (11 and 12) at Hood expected position, then switched (even if quickly) fire to PoW and finally fired a first salvo (13) hitting the compass platform at 6:00:50.....
Simple: salvo 9 fired at 5:59:50, salvo 10 at 5:59:51, time of flight ~ 24-26 sec, strike time 6:00:15, explosion until 6:00:20.
Reload time 20 seconds AFTER salvo 9 and 10, means salvo 11 ready to fire at 6:00:10, salvo 12 at 6:00:11.

So salvo 11 and 12 in the air, and smoke from heavy gun mostly cleared by 6:00:15/16, time of impact from salvo 9 or 10.

Salvo 13 ready to fire against Hood already at 6:00:30 (salvo 11 + 20 secs) - but fired instead at Prince of Wales with minimal (or no kind of ?) correction.

---

You need to calculate reload times between firings, not between impact and next salvo (in rapid fire mode, as I udnerstand it, the guns were firing at maximum rate of fire towards the projected target course, WITHOUT waiting for fall of shot).

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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Mon Feb 22, 2016 11:47 am

@Alecsandros:
Hi Alec,
I see and agree that we have a "theoretical" time to re-load and fire again a full salvo to Hood, after the fatal one.

However, this would not match the RoF that Bismarck demonstrated during the whole firing action (it is quite quicker in this timeframe, having to switch fire (correction can be minimal but still needed as salvo 11 and 12 are fired to Hood future position, not to the one of her remains) and it would not leave much "space" for the subsequent salvos fired to PoW until 6:03 (we have film and photos of basically all salvos fired after 6:03).......

So, I see a bit difficult to build a complete salvo plot, like Antonio's one, with this assumption. :think:

Bye, Alberto
Last edited by Alberto Virtuani on Mon Feb 22, 2016 12:19 pm, edited 1 time in total.
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Re: Bismarck firing procedures at DS

Post by alecsandros » Mon Feb 22, 2016 12:00 pm

Alberto Virtuani wrote:@Alecsandros:
Hi Alec,
I see and agree that we have a "theoretical" time to re-load and fire again a full salvo to Hood, after the fatal one.

However, this would not match the RoF that Bismarck demonstrated during the whole firing action (it is quite quicker in this timeframe, having to switch fire (correction can be minimal but still needed as salvo 11 and 12 are fired to Hood future position, not to the one of her remains) and it would not leave much "space" for the subsequent salvos fired to PoW until 6:03 (we have film and photos of basically all salvos fired after 6:03).......

So, I see a bit difficult to build a complete salvo plot, like Antonio's one) with this assumption. :think:

Bye, Alberto
... Because Bismarck's rate of fire can be anywhere between 18 to 60-70 seconds or more, there is no real way to know "for sure" the timetable of her projectiles exiting the barrells... On average per 14 minutes she consumed very few shells .... but we know per certain intervals she fired much faster... [23 adn 24 seconds are filmed... 20 and even 18 seconds is mecahnically possible as derived from AVKS]. So, no way of knowing...

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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Mon Feb 22, 2016 2:17 pm

Alecsandros wrote: "So, no way of knowing....."
Hi Alec,
I agree..... we don't have a way to exclude one or the other assumption..... :wink:

Looking at the whole salvo plot, however, we have all 5 salvos fired between the 2 turns (PG film and photos) and we have 5 salvos fired after the second turn (photos) in the last 3 battle minutes (we can even miss images of other possible ones....). Therefore, it becomes a bit difficult to reduce salvos fired in "rapid fire" mode against PoW between 6:00:30 and 6:02:40 to just 4 of them: 26 total -12 Hood - 10 (5+5) after 6:03 = 4 ......

It would mean that Schneider deliberately slowed down fire to an unbelievable low rate when he was fully on target against PoW and all witnesses said that the British battleship was under a rain of heavy fire from BS and PG..... :think:

Bye, Alberto
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Re: Bismarck firing procedures at DS

Post by alecsandros » Mon Feb 22, 2016 2:25 pm

Alberto Virtuani wrote:
Alecsandros wrote: "So, no way of knowing....."
Hi Alec,
I agree..... we don't have a way to exclude one or the other assumption..... :wink:

Looking at the whole salvo plot, however, we have all 5 salvos fired between the 2 turns (PG film and photos) and we have 5 salvos fired after the second turn (photos) in the last 3 battle minutes (we can even miss images of other possible ones....). Therefore, it becomes a bit difficult to reduce salvos fired in "rapid fire" mode against PoW between 6:00:30 and 6:02:40 to just 4 of them: 26 total -12 Hood - 10 (5+5) after 6:03 = 4 ......

It would mean that Schneider deliberately slowed down fire to an unbelievable low rate when he was fully on target against PoW and all witnesses said that PoW was under heavy fire from BS and PG..... :think:

Bye, Alberto
... We get back to the first "rapid salvo" sequence - which we know was ordered after the 3rd semi-salvo, impliyng 5:56 or 5:57 at the latest.
As we know, Bismarck fired 5 or 6 full salvos (10 or 12 semisalvos) vs Hood, in 5 minutes. Deducing the 3 original ranging semisalvos, we remain with 7 to 9 semi-salvos fired in rapid firing mode between 5:56/57 and 6:00. This further translates to a minimum of 28 shots per 4 minutes and to a maximum of 36 shots per 3 minutes... Further translating to 0.875 to 1.50 shots per minute per gun... ORDERED, not effectively fired... [and that taking HOod's demise at 6:00:00, becaues if we go to 6:00:30, the rate of fire further drops.. toward 0.750 and 1.30 spmpg respectively]

Does that seem like "rapid fire mode" ?

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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Mon Feb 22, 2016 2:53 pm

@Alecsandros:
Hi Alec,
yes you are right, but also only 4 salvos fired between 6:00 and 6:03 would be a very slow "rapid fire", therefore IMHO we have to admit that BS rapid fire was not so rapid at this stage of the battle (from 5:58 till 6:03) and that the maximum RoF was posibly during the "Gabellgruppe" salvos.....

Any help from someone deeply knowledgeable to better understand German firing practices will be more than welcome ! :wink:

Bye, Alberto
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Re: Bismarck firing procedures at DS

Post by tommy303 » Mon Feb 22, 2016 7:34 pm

Hi Alberto,

There were several methods of directing and firing the guns which could be used aboard Bismarck. One was to fire from the central fire control Rechenstelle by means of the main gyro and artificial horizon. In this method, the directors acted like the director pointers of WW 1 German ships, keeping the guns on target and calling down corrections, but letting the central fire control people do the actual firing. This would have been used initially until range was found, but was a bit slower than other methods as one had to wait for the gyro to fire the guns once the firing key was pressed, but insured better grouping of shells within a salvo.

A second method was similar to the British fire by director control tower. In this the action circuit was set to director and the faster local director gyro took over. This was suited to rapid fire once one had the range, and although the errors generated by the local gyro were greater than the main gunnery gyro, they could be rapidly corrected at the director. Firing was done from the director by the director layer.

A third method, usually done from the Rechenstelle if the ship was maneuvering or subject to heavy seas was to set the guns to fire at an angle in the role calculated to have the shells leave the muzzles at optimum angle or as the ship passed an arbitrary point in a turn.

It is possible Schneider may have used all three of these methods during the battle-- perhaps initially the first firing from central, then the second once range was found, and then, if indeed Bismarck was maneuvering to avoid PoW fall of shot the third. Unfortunately we will probably never know at this point. It is equally possible that there may have been errors in drill or mechanical problems (both of which affected Prinz Eugen during the action) that caused Schneider to slow down the rate of fire, or he might have been firing slow to conserve his supply of APC ammunition.

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Re: Bismarck firing procedures at DS

Post by alecsandros » Mon Feb 22, 2016 8:12 pm

Many thanks Thomas,

Could you please tell us if you consider Bismarck's salvo chasing as a continous sinusoidal track, along the base 220* course ?

Also, I seem to remember you once worte about meeting with the Baron von Mullencheim. From the discussions with him, and from your research, do you think the "93 shells" figure fired by Bismarck during the battle for Denmark Strait is a reliable and definitive number ?

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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Mon Feb 22, 2016 9:06 pm

@ Tommy303,
Hi Tommy,
many thanks from me too !
I agree BS could have used all three firing methods during the battle, even if I'm not convinced that BS was maneuvering at all during the initial phase of the battle (until 6:03) looking at the dreadful precision of her fire..... As soon as she actually maneuvered (hard, I admit) to avoid torpedoes, she lost her target forever.... :think:

Some questions more, if I may ask you, as I'm really ignorant re. German firing procedures, related to the distribution of the fire between fore and aft turrets.

I see in Antonio proposed salvo plot a kind of "PoW like" distribution (I mean A+B and then C+D when PoW was firing odd and then even guns). While this assumption doesn't change much the salvo distribution during the 14 mins battle, is it correct even when in rapid fire ?

In case it is always like this (except I guess the "gabelgruppe"), are A+B firing (let's say 20 seconds) before C+D, then after other time(e.g. 20 seconds) A+B firing again and so on, or are A+B firing followed by C+D at 1 to 2 seconds distance, then (e.g. after 40 seconds) again A+B and immediately after C+D ?
The first one is in line with Capt.Leach testimony, that he saw the fatal salvo landing with 3 shells only, therefore one should have hit.....if salvos were fired in the second way, he should have seen 7 splashes and not 3...... (difficult to distinguish between splashes separated by 1 or even 2 seconds as the columns are growing and decreasing for almost 10 seconds, see the PG film)

One last question: are Germans ALWAYS firing together the guns in a single turret or are you aware of special circumstances when only 1 gun in a turret can be ordered to fire ?

Thanks in advance for your help here.....

Bye, Alberto
Last edited by Alberto Virtuani on Mon Feb 22, 2016 9:28 pm, edited 3 times in total.
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Re: Bismarck firing procedures at DS

Post by Antonio Bonomi » Mon Feb 22, 2016 9:07 pm

Hello everybody,

@ Alecsandros

sorry, I thought that the 93 shells fired by Bismarck was a well realized evidence by everybody.

Here you have 2 samples from OKM 15543 document and from Adm Raeder briefing to AH.
Bismarck_93_fired_shells.jpg
Bismarck_93_fired_shells.jpg (91.04 KiB) Viewed 1677 times
The same number was sent by Adm Lutjens into a radio message to Germany : 93 shells AP fired by Bismarck on the engagement with Hood / PoW.

Obviously we do not know how many guns have been ordered to fire.

That is why I assumed 104, ... missing 11 ... but as I wrote it can be any number from 96 to 120 or even more.

Prinz Eugen fired 157 shells out of 184 gusn ordered to fire, missing 27 shells = 85,32 %

Using same 86% percentage for Bismarck, it will be 108 guns instead of 104 guns ordered to fire, ... with 27 salvos ... :think:

@ Tommy 303,

many thanks for your inputs and cooperation, that is exactly what we need to realize now, ... the German firing procedures and methodology.

Bye Antonio :D
Last edited by Antonio Bonomi on Mon Feb 22, 2016 9:11 pm, edited 1 time in total.
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Re: Bismarck firing procedures at DS

Post by alecsandros » Mon Feb 22, 2016 9:10 pm

@Antonio,

AFAIK, the ONLY primary source pertaining to the number of shots fired by Bismarck was the famous Luetjens message ... which is ... difficult to understand precisely. [ex - running battle 208 to 180hm with Hood - which is not correct in the way we see the battle today. However, for Luetjens it may have meant something else...]

This information coming from this message, has been propagated in all other documents, including the Baron's memoirs...

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Re: Bismarck firing procedures at DS

Post by tommy303 » Tue Feb 23, 2016 7:41 pm

@Alecsandros:

I agree with Antonio that the 93 shells expended is probably the correct figure; afterall, it comes from Luetjens' situation report and he uses "nur" to emphasize the unexpectedly small exenditure of main battery ammunition. I think initially Bismarck adopted a fairly steady course so as to allow Schneider to come on target and find the range. Indeed, salvo chasing is almost as hard on one's own gunnery as that of the enemy. I am not convinced that Bismarck actually did any great amount of salvo chasing as it is. Most of the maneuvers seem to have been in response to warnings from Prinz Eugen about torpedoes and perhaps attempting to take the lead and avoid a possible collision with Prinz Eugen (the latter seems to have been a bit all over the map).

As to Schneider's order for a Gabelgruppe, it appears this was fired in the usual fashion of normal spacing between salvos instead of the Schnelleinschiessen where all three salvos are fired so rapidly that all are in flight at the same time. It would appear from a comment by Paul Schmalenbach (and discussed post war with the Baron), that Schneider saw the first salvo over and the base salvo straddling and was able to cancel the final short salvo of the bracket group and begin firing for effect.

@Alberto,

Bismarck's usual fire routine would be turret groups alternating between the fore and aft batteries (A+B and C+D) with intervals in between to allow one battery to reload while the other was firing. This would keep the enemy under fairly constant fire with short intervals between shells arriving, while still allowing for good spotting and corrections to keep on target. When Schneider saw his base salvo of the Gabelgruppe straddling, he ordered "Vollsalven, gut, schnell) or literally rapid broadsides. It is possible the short delays between the fore and aft turret groups may have been broadside fire but with the gunnery gyro closing the circuits at slightly different times for the two groups, indicating perhaps that the firing was still being down from the gunnery plot.

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