Fire control, salvo patterns, twin-gun turrets vs. triples

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johnmk
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Fire control, salvo patterns, twin-gun turrets vs. triples

Post by johnmk »

Hi folks,

Please forgive me for asking so many questions. Feel free to only respond to one or two of my questions, if that's all the time you can spare for me, I'd appreciate even that. I know there have been discussions on this issue but I believe my questions to be of a more particular nature. For example, I find the 9 guns vs. 8 guns part of the debate to be only a minor facet of the discussion. I'm more interested in salvos, economy and efficacy of fire & spotting over time, and so on.

This basic question has long occupied my mind. Which setup is the superior one? Is it Bismarck's four twin-gun turrets or three triple-gun turrets? How much weight is saved by having a single triple-gun turret in the rear (in addition to two triple-gun turrets up front) by not having to run propeller shafts a bit longer? What are the other weight savings inherent in the three triple-gun design, in detail?

We must also consider the effect on fire control, type of salvo (half salvo, 1/3 salvo, full salvo, etc.?), economy of distribution of ammunition (to the target) over time, and of course, we need to "win." I believe Bismarck fired half salvos, that his to say each turret fired one gun per salvo. Did this method continue at pretty much all times, or did they switch to 8-projectile broadsides in certain settings? How would a three triple-gun turret ship handle its salvos, both early for ranging, middle, and later? How did turret whip affect the accuracy/salvo setup of triple-gun turrets vs. twin-gun? Did dealing with the potential or reality of turret whip lead to suboptimal utilization, relatively speaking, of one type of turret vs. the other, with regards to salvo setup or anything else?

Another consideration is that should it choose to break engagement, Bismarck could bring two turrets to bear on the enemy. This seems like an advantage to me, except that with a three triple-gun turret setup perhaps you could pack in another 10,000-20,000 SHP with the weight saved, or am I wrong there? How would a single triple-gun turret perform in such a situation with regards to salvo setup, etc.

There are probably a thousand other questions I could ask, but at this point I'm sure you catch my drift. Did Bismarck get it right? Was it worth the trade-offs, were the advantages appreciable?

Sincerely,

-John
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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by dunmunro »

A few points:

Bismarck seemed to use 1/2 salvos, so for example, all 4 forward guns would fire, then a few seconds delay and then the after turrets would fire. The question really isn't about 9 guns versus 8 but about 2 or 3 turrets versus 4 and whether an fore and aft or all forward arrangement was best. The actual weight saved for 3 turrets versus 4 is minimal in the turret weights alone, but substantial when the weight of the additional barbette, main belt and deck armour extension to cover the extra turret/barbetter are considered.
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johnmk
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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by johnmk »

Dunmunro, thank you for your reply.

Generally, how did three triple-gun turret ships arrange their salvos, early on at distance and as time progressed? Specifically, did the Germans have the same or a different philosophy with Scharnhorst & Gneisenau?
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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by tommy303 »

In Scharnhorst and Gneisenau, turret salvos were normal, with the three triple turrets fired in sequence. In Bismarck and Tirpitz and the Hippers salvos by turret groups was used A+B followed by C+D.

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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by lwd »

It's worth remebering in this that both in number of turrets and in number of guns there are more options. Many earlier BBs had more than 4 turrets. The Montana class was also to have 4 but tripples. Both the French and the British experimented with 4 gun turrets as well. They tended to have teething problems but these were solved over time. So what then is the criteria for determining the superiority of one system over another?
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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by tommy303 »

The German AVKS ordnance testing department considered two-gun salvos to be the barest minimum necessary to evaluate a fall of shot pattern and preferred a four gun salvo in case one gun misfired or was unable to participate in the salvo; a missfire in a two gun salvo reduces it to a one gun pattern which is difficult to assess. In three gun turrets, a turret salvo of three shells was sufficient to allow for a missfire and still have something to work with, hence in three gun vessels, turret salvos were the normal proceedure while in twins, turret groups were used.

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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by Bgile »

An interesting question is why the Germans chose salvoes by turret group and the British chose salvoes by half the guns in all turrets. I've even seen a photo of Rodney (or Nelson) with the two outside guns raised in one turret and only the center gun in the next one.

The older US ships had all guns in a turret in the same cradle, so they had to be elevated together.
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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by tommy303 »

The main reason was in British turrets the hoists were independent and could be raised or lowered separately, thus permitting guns to fire in alternating salvos. In German turrets, although the guns themselves were independent, the hoists were not and were raised by the same set of motors, i.e., the hoists rose to the gunhouse and returned to lower quarters together--one of those apparently rare attempts at simplification in German WW2 era designs.

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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by Bgile »

tommy303 wrote:The main reason was in British turrets the hoists were independent and could be raised or lowered separately, thus permitting guns to fire in alternating salvos. In German turrets, although the guns themselves were independent, the hoists were not and were raised by the same set of motors, i.e., the hoists rose to the gunhouse and returned to lower quarters together--one of those apparently rare attempts at simplification in German WW2 era designs.
Interesting! I learned something today!
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Karl Heidenreich
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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by Karl Heidenreich »

tommy;

This arragement of hoist in the British ships was only for the quadruple turrets or all of them? Can we point out that maybe that independent, and likely complex, system was one of the reasons of the troubles PoW had at DS?

Best regards,
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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by tommy303 »

Well one of the most reliable turrets used by the British was the 15-inch and it had the same arrangement of independent hoists allowing alternating gun salvos. The problems with the 14 inch turrets of KGV class was the very complex sets of safety interlocks and flash protection all along the ammunition supply route, and poorly designed shell transfer cars which did not have adequate anti-surge stops to prevent shells from shifting when the ship was rolling heavily or manouvering violently. The Nelsons had their share of turret problems as well, but in their case, crews had over a decade to get them working properly. I am sure that given a decade of peacetime to sort things out and make modifications, the KGVs would have been quite reliable as well.

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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by Karl Heidenreich »

And what about disppersion? We know that French and Italian naval artillery had disppersion problems. What about the quads from the KGV?
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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by tommy303 »

The KGVs seem to have had quite respectably small dispersion patterns, so their quads did not appear to suffer from problems evident in French and Italian service.

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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by Karl Heidenreich »

Thanks!
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Re: Fire control, salvo patterns, twin-gun turrets vs. triples

Post by Herr Nilsson »

Bgile wrote:An interesting question is why the Germans chose salvoes by turret group and the British chose salvoes by half the guns in all turrets. I've even seen a photo of Rodney (or Nelson) with the two outside guns raised in one turret and only the center gun in the next one.

The older US ships had all guns in a turret in the same cradle, so they had to be elevated together.
General Admiral Witzell, who was head of the “Waffenamt” of the German Naval High Command, stated that the advantage is that interferences by shock effects in the turret and by blast effects and smoke to the ship’s command and fire control would only occur every second half salvo. By firing with one gun of all turrets you would have the interference every half salvo.
Regards

Marc

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