6x 20", 9x 18" or 12x 16"??

[mariandavid]

No gun systems are perfect - all weapons and ammunition were to some degree compromises. For example the famed US Navy 16" was, in some ways, a seriously flawed weapon (eg light construction meant inaccurate shooting till 'warmed up'). The US had a better 16" gun in the form of the Army coast-defence weapon. Similarly the famed 'super-heavy' USN shells were also a compromise. All major navies had tried such but abandoned this very simple idea. Reduced to simplicity they were created by reducing the HE (the 'burster charge') and replacing the cavity created with steel. Very nice when penetration to a critical detonating point is needed, but resulting in relatively feeble damage compared with other rounds. For example the (few) accounts of the Kirishima imply that the impact of the 16" hits was so small that they were not even noticed! And as fps noted above even non-AP (!!) 14" hits on the South Dakota knocked her out of action.

There is also a tendency to 'worship' the features of the Iowa class - not surprising since these magnificent designs were the only ones to survive into the modern period. However compared with their European contemporaries they placed an unhealthy emphasis on speed over protection for ships of their displacement.

The other problem is that discussions of this type tend to assume BB v BB over unlimited periods of time, invariably starting with optimum visibility conditions, with matching beliefs that variations in speed allow one ship to dictate its own optimum firing distance. Of course in the real world far more variables apply. In addition the European navies were influenced by their real life battle experiences in limited and changeable weather conditions which dictated that what mattered was to achieve the maximum number of hits in the smallest period of time; seen by the RN 12x 14" guns of the KGV initial design.

Rotating back to the original question - my optimum would be something like the USN Montana class - an infinitely better balanced creation than the Iowa. So 12x 16 but with emphasis given to protection of all areas (not the dreaded "all or nothing") backed up by the most effective fire-control and damage control systems.

[wyrmmy]

According to Friedman, the Montana's used a modified 'All or Nothing' armor scheme, and actually reduced or eliminated armor from some areas to increase deck protection (e.g. armor from the 'box' to the stearing gear armor was reduced to armored tubes protecting the wiring harnesses).

[Zemke]

I think is depends more on fire control rather than on number of guns. All things being equal, then always have more guns, but things are not equal, and what really made the American 16' guns superior was much better fire control technology. Go with 16' guns with the best fire control money can buy and the rest is easy.

[bklooste]

Correct they went with 18" since the Nagatos were almost proof against their own 16" guns and any new one certainly would be,

Also this Q is for the A150 which is post Yamato.

ORIGINAL: Shark7

ORIGINAL: bklooste

Your all using the US 16" guns the Japanese 16" guns prob couldnt penetrate the Iowa making 3*3* 18" a better choice amd fpcis on speed so you can keep them at 28K yards..

Yes, but Iowa's didn't exist at the time of Yamato's design. You can't plan for a ship you know nothing of. One can assume that the Japanese designers did take into account that given Yamato's design armor it was a safe bet other ships could and would carry as much armor protection thus requiring a heavier gun to over-come it.

Yamato laid down in 1937...
Iowa laid down in 1939...

Forgetting what we know, and looking strictly at the history of the designs, Yamato was not planned as an Iowa killer, and the Super Yamato's would have been laid down before the first Iowa saw action, had they not been cancelled. If the Japanese got the Iowa spec's before hull completion of the Super Yamato's, they might have been able to change to a 4 turret layout, but in reality, they probably would have remained a 3 turret layout.

Just my $.02

[bklooste]

I dont think radar FC makes any different durring day battles ...Im pretty sure the optical range finders and on the Yamato were superior.  At night though 100% true and she would be hit when she could not see her oponent.

[Terminus]

Japanese rangefinders were in no way superior. At best equal.

[JuanG]

The quality of Japanese rangefinders and optics was superior, and in the case of night optics, significantly so, compared to US or British ones.

However, Japanese firecontrol as a whole system was at best comparable to early war non-radar USN firecontrol despite this advantage, as the USN's use of the stable vertical/element and RPC made up for this, along with more advanced FC computers.

Once you add in radar the situation becomes more skewed, though in all honesty I think a lot of people overstate the advantages of radar for daylight combat, as it is only superior to optical means for range determination, not bearing. I suppose the biggest advantage would be ease and speed of target aquisition and ranging, after that its still just a matter of chance if you get a hit or not. At night however, it was clearly a decisive advantage, Japanese night optics or not. It should be worth noting though that even the latewar radar sets were rather fragile, and in a BB vs BB fight, a hit from a major calibre shell might well mean the loss of a radar set. Good thing USN BBs carried several I guess.

To answer the question the topic is about though, out of those proposed I would think 9x18" the most balanced configuration, though 12x16" would be preferable for close range nighttime combat, where shell time of flight is not a significant factor in rate of fire and there is no avantage to the 18" or 20" in terms of penetration (ie, all of these would likely penetrate any ship afloat in a Guadalcanal style battle).

[Terminus]

Superior at the beginning of the war, maybe, but not by much. When the second half of the war rolled around, no longer.

[John Lansford]

In Friedman's book on US Battleships, he included damage evaluations of South Dakota and where the shells impacted.  IIRC all the hits were from 8" or smaller shells, only one 14" shell hit was found, and that was in a radar mount high on the superstructure.  The electrical failure the ship experienced came from the vibration of her own guns firing that threw out several circuit breakers, not from shell damage.

[mikemike]

ORIGINAL: herwin

The DKM was not limited to 8" in heavy cruisers--non-signatory to the various navaltreaties. The pocket battleships were replacement for pre-dreadnought battleships; hence the calibre. However the turret layout was inefficient.

The Renown was found to be a very efficient carrier escort. The gun calibre tended to overawe potential opponents.

Do you mean before 1933 or after? Before Hitler, the German Navy (at that time still Reichsmarine) was ruled by the Versailles Treaty which stated that Germany was allowed to possess:

8 battleships (maximum displacement 10,000 tons, 2 in reserve)
8 cruisers (maximum displacement 6,000 tons, 2 in reserve)
16 destroyers (max. displacement 800 tons, 4 in reserve)
16 torpedo boats (max. displacement 200 tons, 4 in reserve)

Furthermore, the Reichsmarine was allowed to keep as ship's armament
38 280 mm guns (main armament for the battleships),
128 170/150 mm guns (secondary armament for battleships, main armament for cruisers),
144 105/88 mm guns,
204 torpedo tubes (Article 181 of the Versailles Treaty)

While it was nowhere explicitly stated that the battleships had to use 280 mm guns, the cruisers 150 mm, the destroyers 105 mm, the Interallied Control Commission enforced this in practice. There were plans to arm later cruisers with 190 mm guns in twin turrets, or destroyers with 127 mm guns, but the navy was in each case informed that the Allies regarded this as violation of the treaty. In view of these limitations, it is hardly surprising that the resulting designs were eventually unsatisfactory.

Hitler eventually ignored the Versailles Treaty, but the German-British naval treaty of 1935 bound the Kriegsmarine to the definitions of the Washington Treaty and the 1930 London Treaty, which made the Panzerschiffe officially battleships. That the Kriegsmarine re-rated the ships as CAs was on the one hand acknowledgment of their intended role - classical guerre de course - and on the other hand downplaying for propaganda purposes. The ships were always stunted bastards begotten by Versailles, neither fish nor fowl.


HMS Refit and HMS Repair were typical Fisher brainchildren - big, imposing, fast, carrying big guns, and well-protected against machine-gun fire. It was probably a good thing the weather was so bad when Renown went up against Scharnhorst and Gneisenau off Norway in 1940. Under the same conditions as when Glorious was caught, Renown would have been in real trouble, even when only being confronted with 280 mm shells. Those ships were probably not significantly sturdier than the Kongos. At least Renown had decent AA armament which made the ship suitable as carrier escort, but Repulse was essentially good only for showing the flag.

[Tiornu]

If we assume a 2700-lb 16in shell with the larger shells being of equal proportions, then the broadsides work out to this:
12 x 16 = 32,400 lbs
9 x 18 = 34,600 lbs
6 x 20 = 31,640 lbs
Give or take. Note that I'm using exact inches for the bore measure.
The largest gun gives you more penetration. Do you need more penetration than an 18in shell can give you?
I'm in agreement with Sardaukar regarding ten-gun ships, purely on aesthetic grounds.
The Germans did not "get" triple turrets. They got a copy of the Nevada plan and had a howling good time making fun of the triple turrets, assuming the center gun could not be adequately supplied with ammo. perhaps that was due to exposure to the Austrian triple 12-inchers. In fact, American gunnery operations differed significantly from what the Germans were used to, and ammo supply was not a problem. Even decades later, the German prejudice against triples remained strong. Even the triple 15cm mounts gave way to twins in the final CL design.
"Armored ship" was a common rating in European navies before WWI, so its application in the Versailles Treaty hardly seemed unusual at the time.
If you go back to the "Monster Gun" phase of the pre-dreadnought period, you'll find 17in guns and a few other calibers above 16in.
The bow of the Iowas was designed to be as narrow as possible to limit the consequences of hits there.
The Montanas certainly were AoN ships, though that bomb deck was a blemish. Coincidentally, the reduction of armor between the citadel and the steering is similar to what you'd see in the like-sized Yamato.
Nagato was quite vulnerable to 16in shells.

[John Lansford]

The Germans didn't appear to have any problems with their triple 11" turrets on the Graf Spee and Scharnhorst classes though.

RE: Iowa's narrow bow form.  I've not gone below deck when we visited the Missouri, so I don't know what the layout of the bow compartments is, but it can't be very extensive.  A shell detonating forward of the main turrets may not hit anything important, but it would certainly affect her maximum speed, perhaps even severely. 

[Dili]

That happens with all battleships, everyone is vulnerable to comparatively light hits outside its armored part. Directors can be damaged or destroyed, secondaries usually with only thin plate can be penetrated, AA amno can explode, etc etc.

[Tiornu]

The Germans apparently felt their system of gunnery control was better served by twin turrets. I believe that was the deciding factor in returning to twins.
Subdivision in the Iowa bow was relatively elaborate. The good news for the narrow cross section was the increased possibility of a shell passing through without exploding.

[castor troy]

ORIGINAL: Tiornu

The Germans apparently felt their system of gunnery control was better served by twin turrets. I believe that was the deciding factor in returning to twins.
Subdivision in the Iowa bow was relatively elaborate. The good news for the narrow cross section was the increased possibility of a shell passing through without exploding.

what´s the difference in fire control between a twin turret and a tripple turret (or even a quadruple turret)?

[John Lansford]

The Germans used a method of rangefinding that was more accurate at initial engagement ranges, but tended to fall off as the battle wore on due to strain by the operators.  That put a premium on getting the maximum number of shells downrange as quickly as possible, and twin turrets were faster to load and fire than triple turrets were.  I suspect that's why they had a preference for twin vs triple turrets, although it doesn't seem to have affected Scharnhorst's accuracy in the battles she was in.

[mikemike]

German practice, in WWI as in WWII, was to fire half-salvos (one barrel per turret) which halved the time between salvos and reduced time to find the range even more. This was easier to manage in twin turrets, where the ROF of all guns was identical. Destroyers in WWII fired 3-5 salvos at the maximum ROF in a pre-calculated "ladder" (I guess an "up ladder" to better separate the salvo impacts) to minimize the time to find the range.

The German abhorrence of more than two guns in one turret was also based on an unwillingness to over-concentrate the guns. If you use quad turrets, as the French did extensively and the RN with the KGV class, a single hit on a turret will disable four guns at once (this happened to Strasbourg at Mers-el-Kebir IIRC). You will notice that the turrets on Richelieu were very widely separated, because the risk of losing all heavy guns to a single hit was obviously taken very seriously by the French Navy.

[Tiornu]

The British came out of the Battle of Jutland with the impression that German stereoscopic rangefinders caused a downgrade in performance as actions dragged on, but I don't know if anyone agreed with that assessment. The British were the only major fleet that failed to adopt stereoscopic rangefinders as standard before WWII. The Americans kept single coincidence rangefinders in their modern BBs for the specific purpose of fixing on spotlights during night engagements, but the advent of radar prompted their removal.
It was Dunkerque that suffered the turret hit at Mers el Kebir, and the armored partition within the turret allowed the two guns on the other side to remain serviceable. Ironically, it appears that both Scharnhorst and Bismarck suffered single hits that disabled both forward mounts, at least for a time.
The Germans did work out a system for half-salvos in their triple-mount ships, but for some reason they found it preferable to revert to twins. I can understand why the Scharnhorst mounts might have left a bad taste in the KM's mouth, but why the 15cm triples? These were good mounts, perhaps the best feature of the German CLs.

[mikemike]

ORIGINAL: Tiornu

The Germans did work out a system for half-salvos in their triple-mount ships, but for some reason they found it preferable to revert to twins. I can understand why the Scharnhorst mounts might have left a bad taste in the KM's mouth, but why the 15cm triples? These were good mounts, perhaps the best feature of the German CLs.

I can't think of a better explanation than a deeply ingrained, almost dogmatic, prejudice. I've never understood why the Kriegsmarine fooled around with light cruiser designs that were under-armed and underprotected when all they needed to do was a revamp of the Nürnberg design with more displacement, better protection, a new steam plant, and get rid of the cruise diesels with their shaft. Getting 80k-90k HP from two shafts shouldn't have been a problem. I've always thought that the French "La Galissonniere" class was a good example of what could have been accomplished in this way. But using diesels for cruise power was probably also one of the Kriegsmarine dogmas.

One of the design features of the Reichsmarine cruisers that usually gets overlooked is that at longer ranges (I'd guess above about 30 deg of elevation), both aft turrets had 360 deg arcs of fire (and those triple turrets could be turned two full revolutions to either side, a feature that was inherited by the twin secondary turrets on the battleships that were derived from the triples). I can't think of any other cruiser of the time that was able to fire all its main armament at targets in the forward hemisphere.

[Fallschirmjager]

I would have laid down two carriers and joined the 20th century. [;)]