Bismarck firing procedures at DS

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tommy303
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Re: Bismarck firing procedures at DS

Post by tommy303 » Sat Jun 18, 2016 12:26 am

Yes, one would normally wait for spotting the fall of shot of the deflection salvo before firing the bracket group to test range. There were instances where Bismarck fired deflection salvos very far short--during the reengagement with Prince of Wales and when engaging Sheffield on the evening of the 26th for instance. They may have been fired so far short to reduce the wait for spotting (conjecture on my part), rather than a fault in rangetaking.

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Re: Bismarck firing procedures at DS

Post by alecsandros » Sun Jun 19, 2016 6:12 pm

... If so , was there enough time for Prinz Eugen to fire all those salvos, considering best possible time sequence and rate of reload ?

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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Sun Jun 19, 2016 8:57 pm

Hi Alec,
even assuming 1) PG open fire against Hood at 5:55:30 , 2) a practical max RoF between 2 and 2.5 rounds per minute per gun (theoretical only was 4 to 5 for the German 203 mm gun), and 3) 45 seconds to allow the spotting of falls and adjust as per your suggestion, the 2 full salvos could be fired at 5:55:30 and 5:56:15, with the 3 bracketing semi-salvos fired at 5:57 , 5:57:10 and 5:57:25.

After the order to switch fire, the Vollsalve to PoW could be fired at 5:58:15 (assuming other 25 seconds lost due to the change of target).

The following Gabellgruppe could be fired at 5:58:40, 5:58:50 and 5:59:05, then other 4 semi-salvos (to get to a total of 8 full salvos) at 5:59:30, 5:59:40, 5:59:55 and finally 6:00:05.

As you see, there are still some seconds before Jasper sees PoW heeling and apparently turning toward PG (just after 6:00:30, assuming Hood blew up at 6:00:10). By that time, IMHO, PG could have easily fired 8 full salvos, as per Jasper account, in line with the 5 to 6 salvos fired by Bismarck and the 11 semi-salvos fired by PoW in the same timeframe.


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Re: Bismarck firing procedures at DS

Post by alecsandros » Mon Jun 20, 2016 12:19 pm

Alberto Virtuani wrote: The following Gabellgruppe could be fired at 5:58:40, 5:58:50 and 5:59:05, then other 4 semi-salvos (to get to a total of 8 full salvos) at 5:59:30, 5:59:40, 5:59:55 and finally 6:00:05.
... If the gabellgruppe versus Prince of Wales would have been fired between 5:58:40 and 5:59:05, spotting for fall of shot of that gabelgruppe would have lasted until 5:55:50 (time of final semi-salvo landing around Prince of Wales). Only after that would Jasper order rapid fire. The gabbelgruppe was normally a part of the ranging procedure.

And, summing up, with this time frame Prinz Eugen would total 48 x 203mm shots between 5:55:30 and 5:59:50 (4 minutes 20 seconds). This means 11.08 shots per minute, or 1.385 spmpg. Mui interesante :cool:

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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Mon Jun 20, 2016 12:55 pm

Alecsandros wrote: "....spotting for fall of shot of that gabelgruppe would have lasted until 5:59:50..."
Hi Alec,
you are right, I was too "impatient" to fire "rapid" without spotting the fall of shots of the Gabellgruppe against PoW...... :oops:

I should re-phrase:
.....the following Gabellgruppe could be fired at 5:58:40, 5:58:50 and 5:59:05, then other 4 semi-salvos (to get to a total of 8 full salvos) at 5:59:50, 6:00:00, 6:00:15 and finally 6:00:25."

Still we are (just) "in time" with Jasper account. :wink:


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Last edited by Alberto Virtuani on Mon Jun 20, 2016 1:37 pm, edited 1 time in total.
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Re: Bismarck firing procedures at DS

Post by alecsandros » Mon Jun 20, 2016 1:26 pm

I don't call into question Jasper's account,
Just that rate of fire at the beginning of battle of Denmark Strait seems to have been slow for all ships involved...

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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Mon Jun 20, 2016 6:26 pm

Hi Alec,
yes, you are right: the actual RoF of all ships was low compared to their theoretical max RoF.

However, it was the case also during the following phases of the battle (for all involved ships as well):
PG had a RoF of 1.385 spmpg until 5:59:50, a RoF of around 1.5 spmpg until 6:00:30 (64 shots in 5.3 mins) but in the whole battle of DS the RoF was around 1.6 spmpg (184 shots in 14 mins). Therefore not a dramatic improvement at later stages despite the shorter time of flight of the shells.


The overall figure of 3.2 semi-salvo per minute for PG looks in line (considering the higher RoF of a cruiser) with Bismarck's (1.86 salvo per minute, assuming 108 shells ordered to fire) and PoW's until in central control (1.89 semi-salvo per minute).
Just for our fun, the spreadsheet I have already posted to discuss Bismarck and PoW RoF, (based on criteria and formulas used in the official PoW GAR), with PG data too:
BS vs PoW vs PG_firing DS.jpg
BS vs PoW vs PG_firing DS.jpg (39.07 KiB) Viewed 2553 times
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Re: Bismarck firing procedures at DS

Post by alecsandros » Mon Jun 20, 2016 8:16 pm

... yes but those are cumulative averages... If You start "cutting" the battle into several pieces, and analyse rate of fire per piece, instead of accumulating until given time point, You will see substantial differences between pieces.

For example, if Prinz Eugen fired 48 shots (misfires unknown) in 4,33 minutes, and 184 "shots" in 14 minutes, then by substraction, 184-48 = 136 shots fired in 9,66 minutes, including 3 course changes which Jaspers mentioned, that were likely to throw off own gunnery and require new target aquisition procedure (ranging).

Also, further "cutting" the 5:59 - 6:09 timeframe , we know that PE made an abrupt course change at ~ 6:04, due to torpedoes in the water (3 of which were claimed to have been seen by 2nd Artillery Officer, IIRC...) The ship continued to fire on Prince of Wales with aft artillery only (as mentioned in Jaspers's section of the log), so rate of fire of the entire ship was reduced, as the forward battery could not train on the enemy. So even if the aft guns fired rapidly, that wouldn't be shown in the overall average of teh battery fire.

For those reasons , I think PRinz Eugen manifested a high rate of fire between 5:59:40 (?) and 6:04 (time of torp alarm), firing IMHO 80 to 100 "shots" (ordered) in that time frame*.

----

* That would leave 36 to 56 shots ordered between 6:04 and 6:09... That is, through the hard turn to avoid torps... and then through the smoke screen put up by Prince of Wales...

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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Tue Jun 21, 2016 7:14 am

Alecsandros wrote: "...I think PRinz Eugen manifested a high rate of fire between 5:59:40 (?) and 6:04 (time of torp alarm)...."
Hi Alec,
while your considerations make a lot of sense in theory and and it should be logical that PG fired more rapidly before the turn at 6:04, I have several doubts (at least based on the English translation of Jasper's account)..... :think:

Jasper report is clear until 6:04 (turn due to torpedo alarm), however then he says:
PG_turn.jpg
PG_turn.jpg (95.74 KiB) Viewed 2517 times
As you see Jasper mention salvo 28..... :shock: We know PG ordered to fire 184 rounds (firing 157 actual, thus only 23 full salvos). Therefore salvo 28 should be semi-salvo 28 (full salvo 14).
If this is the case, PG fired quite slowly until 6:04 because we know from Jasper's previous paragraphs that she fired 8 full salvos until 6:00:30, therefore after 6:00:30, in 3 minutes and half, Jasper fired only 6 full salvos, less then 1 spmpg..... :shock:

If we accept Jasper account (and I'm not sure we should in this case), one explanation can be that PoW changed course sharply, messing up the calculations for the fire solution of PG......

In addition Jasper says that, at the 28th salvo, he passed the control to Albrecht in the aft director, but it is unclear whether the fore turrets were unable to fire or whether they were just trained max aft and the change was only due to smoke obscuring the main director..... :think:

What does it mean "partial salvos"? Just another translation for semi-salvos or salvos fired by the aft turrets only ?

In any case, between 6:04 and 6:09 PG, under Albrecht control, should have fired an enormous amount of shells (9 full salvos in less than 5 minutes or even 18 semi-salvos of aft turrets, in this last case almost achieving her theoretical max RoF).

I do think there is something wrong in Jasper account or in the English translation. I kindly ask whether a German speaking friend (Marc ???) can help here.

Bye, Alberto
Last edited by Alberto Virtuani on Tue Jun 21, 2016 7:41 am, edited 4 times in total.
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Re: Bismarck firing procedures at DS

Post by alecsandros » Tue Jun 21, 2016 7:27 am

@Alberto
You are right... :think:
Any help would be much appreciated

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Re: Bismarck firing procedures at DS

Post by Herr Nilsson » Tue Jun 21, 2016 11:25 am

Partial salvo means it's not a full salvo. You can call it semi salvo, if you wish.

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.
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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Tue Jun 21, 2016 11:39 am

Hi Marc,
many thanks for the clarification: I will try to better fit Jasper account and salvo count based on this. :think:

One more question: does the German text specifies whether the PG fore turrets were not bearing (thus not firing) or just trained max aft (but still in action, as the English translation does not exclude) when Jasper transferred direction to Albrecht ? Still I feel that, even accounting for 28 salvos (either partial or full), there will be too many shots to be fired after 6:04 by just 2 turrets before cease fire.

Thanks a lot (as usual).


Bye, Alberto
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Re: Bismarck firing procedures at DS

Post by Herr Nilsson » Tue Jun 21, 2016 12:09 pm

Hard to say.

Edit: .... but in this context I tend to "not bearing".
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Re: Bismarck firing procedures at DS

Post by Steve Crandell » Tue Jun 21, 2016 4:01 pm

Alberto Virtuani wrote:Hi Marc,
many thanks for the clarification: I will try to better fit Jasper account and salvo count based on this. :think:

One more question: does the German text specifies whether the PG fore turrets were not bearing (thus not firing) or just trained max aft (but still in action, as the English translation does not exclude) when Jasper transferred direction to Albrecht ? Still I feel that, even accounting for 28 salvos (either partial or full), there will be too many shots to be fired after 6:04 by just 2 turrets before cease fire.

Thanks a lot (as usual).


Bye, Alberto
It would be an incredible coincidence if the turrets were trained in their mechanical stops and were still bearing on the enemy.

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Re: Bismarck firing procedures at DS

Post by Alberto Virtuani » Tue Jun 21, 2016 6:30 pm

Steve Crandell wrote: "It would be an incredible coincidence if the turrets were trained in their mechanical stops and were still bearing on the enemy."
Hi Steve,
yes I agree, of course. However my question was about the possibility that Jasper intended that the fore turrets were trained aft "almost" to their max bearing and thus the fore director, trained the same way, was obscured by the funnel smoke.
On course 270°, the fore turrets should be close to their limit but I'm not 100% sure they were wooded, as the bearing of PoW was between 140°and 145°from PG bow.

In addition, even admitting they were not firing after 6:04 (being wooded), why the report did not mention that they opened fire again after 6:05:30 and up to 6:07:00, when the ship was again on a course around 220° (after the second sharp turn mentioned by Jasper) ?

Still many uncertain aspects in PG firing..... :think:
It's a pity we don't have for the German ships a Gunnery Map and a plot track like the one from PoW, thanks to Rowell and McMullen. :(


Bye, Alberto
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