Effects of types of turret mounting on gunnery

[sjpc302]

Aside from not putting all of your eggs in one basket, is there any reason to choose to use double turrets over triple or quadruple once improved triple/quadruple turrets is unlocked? I have heard someone mention in some youtube comment that it higher gun turrets have other penalties beyond the ROF and reliability penalties that the manual says is "rectified" by technology. The wording of the manual implies that there are no downsides other than what those which are removed by tech though. Does anyone know more about this?

Similarly, are there any effects for using superimposed mounting, or other positions? I ask because I have noticed consistently that my B turrets tend to have slightly more ammunition left in them than the A turrets after a fight, implying they fired less.

Final question that I think I know the answer to - is it correct that the improved turret technologies apply to existing ships? My understanding was it did.

[nimrod]

Varied tech can impact turret choices, I've played a game or two where only single gun turrets didn't have penalties.

Weight increase is the biggest penalty I know of for superimposed turrets. If you check turret firing arch in the ship designer you may notice that some designs have a blind spot (gap) over the bow of the ship - that blind spot may apply to the B turret. I feel that the superimposed turrets get disabled more often, but that is just a feeling... Tried to keep track for a couple of battles, but the numbers were too varied to really mater. Casements have some limitations / penalties especially in bad weather.

Ships need to be retrofitted (simple in and out of the dry dock) for the turret techs to take effect, same with some of the damage control and fire control techs.

[gurudennis]

Early triple/quad turrets suffer from crippling reliability issues (modeled in the game as jamming) and substantial accuracy issues (not sure if properly modeled). These become more mild and eventually disappear with advances in turret technology, but as far as I know such advances do not retroactively apply to existing turrets unless they are explicitly rebuilt/upgraded. Consequently, it makes sense to heavily prefer double turrets at least through the 1920s.

Superimposed mountings are heavier than A/Y turrets, with no other documented downsides. Superimposed B and X are especially important because they offer the best firing arcs without getting in the way of deck-mounted secondaries. All turrets with the exception of A/B/X/Y cause blast effects on turreted secondaries, thus more or less forcing them into casemates. Since casemated guns suffer accuracy penalties in all but the calmest of sea states, there's a significant motivation to run 8-gun configurations with double ABXY before triple ABY or ABXY becomes practical for reasons outlined above. It's also fairly common and practical to build hybrids where AY are triple whereas BX are double (and therefore lighter).

[TheOtherPoster]

I don't think it's terribly important but blast effects on secondary turrets from midship main guns makes sense only if they are unarmoured, like AA guns. But it is a bit of nonsense if the secondary guns are armoured, like during the first part of the game. Maybe the developers could think of cancelling the penalty to secondary guns if, for example, they have at least 4in armour and the main guns are 12in or less.

[vonfriedman]

According to Norman Friedman in the early 1930s, the British estimated that the 16-inch guns in triple turrets of the Nelson-class battleships could only fire at the rate of about 1 shot every 40 seconds against a rate of 1 shot every 25 seconds in the Queen Elizabeth-class battleships with 15-inch guns in twin turrets. The slowdown was mainly due to the more complex handling of 16-inch shells and charges.

[director]

In real life, the issue was mainly width. Three guns and three sets of loading gear take up more room than two, and while you can extend the length of the ship it is harder to justify making the ship wider (consequences including passing through canals, fitting in drydocks and the higher horsepower needed to drive a wider hull).

Bigger turrets weigh more, and larger openings in the deck can pose structural weakness issues. So the tendency is to try to jam all the machinery close together, which makes operating it, and clearing issues and damage, more of a problem.

Triple and quad turrets can suffer from blast effect interference, usually resolved by having one or more guns fire slightly later than the others or by simply spacing the guns further apart - which takes up more width. Mechanical problems like jams can be harder to fix if there is little room in a turret, especially so if loud explosions are taking place next to you and big masses of metal are whipping in and out.


That said, three triple turrets do weigh less and take up less length than four twins (and deliver one more barrel besides), and there isn't any evidence that twin turrets fire faster than triples. The USN's early commitment to triple turrets meant they had mostly resolved the issues by, say, the late 1920s. It may be unfair to compare the 'Nelson' 16" loading time, having an entirely new shell and loading system, to the decades-old tried-and-true 15" twin turret system... that said, I have heard from more than one source that the 'Nelson' class had relatively slow firing guns, on a par perhaps with the contemporary 'Colorado' 16" system, but still slow compared to the later US 16" triple turrets of the fast battleships. I don't know if that was due to magazine arrangement, safety interlocks, speed of loading gear or some other factors.

Fisher was entirely open to fitting triple turrets - and superimposed turrets - as early as 'Dreadnought' but more conservative members of the board wanted twins and non-superimposed. 'Dreadnought', they felt, had enough innovations for one design...

It is difficult to peg rate-of-fire with precision, due to the ranging fire/fire for effect method used, and due to tricks like stockpiling ammo in order to get off a few very quick shots, but - in general - 3 shells in two minutes is a pretty good average rate for large caliber guns and 4 shells in two minutes is about the best that can, on average and over time, be done.


TheOtherPoster - even an 'armored' secondary turret like the standard US twin 5" battleship and cruiser mount can suffer from blast effects because they are not airtight. The rate-of-fire reduction might come about from ear pain (from the air pressure wave) or simple deafness from the noise.

[wlbjork]

Feb 12, 2022 3:54:18 GMT -6 vonfriedman said:

According to Norman Friedman in the early 1930s, the British estimated that the 16-inch guns in triple turrets of the Nelson-class battleships could only fire at the rate of about 1 shot every 40 seconds against a rate of 1 shot every 25 seconds in the Queen Elizabeth-class battleships with 15-inch guns in twin turrets. The slowdown was mainly due to the more complex handling of 16-inch shells and charges.

A little more detail:

From NavWeaps:
The following description is adapted from "British Battleships of World War Two:"

The designed loading-cycle for these mounts was 30 seconds, but in practice, it was 35 seconds for one gun. As the shell loading in the handling rooms required 50 seconds, the maximum sustained rate of fire was one round per gun every 50 seconds. However, because of the necessity of firing wing and center guns of turrets in different salvos [in order to reduce dispersion problems], the firing rate was further reduced to one round every 60 to 65 seconds. Even with modifications, the Director of Naval Ordnance considered it extremely doubtful that a greater rate of fire than one round every 40 seconds for the first four rounds and one round every 45 seconds thereafter would actually be achieved.

The book cited would appear to be by Raven and Roberts.

www.navweaps.com/Weapons/WNBR_16-45_mk1.php

[director]

The US solved the interference problem by putting a split-second delay on the inner barrel of the triple turret, or later by spacing the barrels out wider. It is curious that the British triple turret was slowed by 10 seconds for this.

But the main idea we should take away is that triple turrets will cause issues when first introduced, and those issues can be resolved by time and especially so in later designs.

[vonfriedman]

On the Naval History and Heritage Command site there is a remarkable photograph of the USS Missouri firing a salvo with the six guns of her fore turrets, in which the six shells are clearly seen quite spaced apart.

[gurudennis]

Feb 12, 2022 3:09:21 GMT -6 TheOtherPoster said:

I don't think it's terribly important but blast effects on secondary turrets from midship main guns makes sense only if they are unarmoured, like AA guns. But it is a bit of nonsense if the secondary guns are armoured, like during the first part of the game. Maybe the developers could think of cancelling the penalty to secondary guns if, for example, they have at least 4in armour and the main guns are 12in or less.

I would support a reduction in blast effects for armored turreted secondaries, but a total elimination wouldn't be fair. Secondary turrets IRL would have faced several major blast-related issues even when armored:

1. Secondary turret optics are delicate enough to be knocked out by a high-caliber blast. This was occasionally an issue even for primary turrets blasting over each other, effectively restricting their permitted peace time firing angles to prevent unnecessary damage to the equipment and injury to spotters (I regretfully forget the precise source for this tidbit).

2. It becomes impossible for personnel to enter or exit a secondary turret that is anywhere near the blast area of primary guns once the engagement has started. This can severely complicate the manning of secondaries and if need be their evacuation.

3. Increased wear and tear.

[charliezulu]

Beyond just delicate optics, early turrets following British practice used sighting hoods instead of periscopes, which made them vulnerable in general to blast - the first British battleship which could fire over the bow "as built", iirc, was Hood.

With regards to accuracy, the difference between triple and 3-gun turrets should be pointed out. Having a common cradle causes a multitude of accuracy issues which are experienced on twin turrets as well.

As for Nelson, I think the simpler explanation is just that the British are demonstrably incapable of designing and building a good ammunition handling system. They should be an outlier in general and ignored whenever possible

(jokes aside, the 16" Mk 1's mountings were of a completely new type radically different to earlier British turrets. They had "much trouble initially" with the shell handling rooms and IMO it is not representative of mature 3-gun turret design in general)