The Ship Model Forum

Recent items on the site (Yamashiro/Fuso, Marat) have prompted me to ask about the layout of the main armament of battleships. Probably most familiar to us is the more or less "standard" arrangement of two three-gun turrets fore, one aft, nine big guns total, with secondaries generally located amidships. Yet looking at the aforementioned examples, from the WWI era into WWII, there are vessels which not only had the big guns fore and aft, but also amidships. While these tended to be two-gun turrets, nonetheless the simple math indicates layouts like this had a numerical advantage (6 turrets x two guns each = 12 guns, vs. 3 x 3 = 9). So from that standpoint alone it would seem that battleship design would center upon a fore-midships-aft arrangement of the main turrets. Yet that came not to be the "standard" layout. No doubt other design issues are involved, fuel bunkerage and machinery space perhaps paramount among them, not much sense in having more big guns if shorter operational range and lower speed were the tradeoffs. Anyway, just a few thoughts...

Actually the "most common" main gun layout on battleships that more or less evolved by the outbreak of WWI was superimposed armament fore and aft. If you look at the battleships with midships turrets, most were designed prior to WWI and carried between 12-in to 14-in guns and were limited to twin turrets (but not always, aka the Russian battleships). Four twin or triple (then three) turrets or combos of those were seen on battleships built by many countries during WWI and after. The reason countries prior to WWI utilized more than four turrets was to increase broadside armament and to keep CG lower. The reasons for going away from the "midships" main armament was due to several factors; introduction of larger guns and even triple turrets maintained the broadside armament while simplifying the layout, allowing for a shorter overall length, made it easier to increase protection and to gain advantages with the power plant protection and operation.

The trend in battleship design was going to larger main armament guns (12-in to 15/16-in), the need for heavier armor, and the desire for greater speed, ALL drove to the fore-aft armament arrangements.

Actually the 3x3 (two forward, one aft) that you described is quite uncommon. Only the last 3 classes of US battleships, plus the Yamato, Scharnhorst and Vittorio Veneto carry this arrangement (plus a few never built). It did seem to become a sort of "optimum" by the end of the battleship era but it was far from being "standard". The British never built a ship with this arrangement, the closest they got was HMS Nelson.

I would say for "most common" you are looking at four turrets, superfiring pairs both fore and aft, usually twin though sometimes triple and sometimes a mix (e.g. USS Nevada). For me 8 guns in four twins is "standard" since that's what evolved as an optimum at the end of WWI. All major navies had this on multiple ships: Hood, QEs, Rs, Colorado class, Nagato, Bayern, Bismarck etc.

There are so many reasons for other arrangements that this could turn into a very long and interesting thread. Here are a few I can think of off the top of my head:

1) Fire control

The twin gun was retained for a long time in most navies because it offered advantages in fire control. Most navies at some time or another use half-salvos so they could observe shell splashes between shots without wasting too much ammo. This is incredibly easy to do with twin turrets, no matter how many you have, just fire all the "left" guns, then all the "right" guns.


2) Damage limitation

For a long time there were many who opposed triple turrets because of the fear that a single lucky shot could take out three guns, as opposed to just two. Similarly, two triple turrets next to each other could both get taken out by a single shot, and that's 2/3 of your armament gone. Ultimately the weight saving of having more guns in each turret won out, but there were many ships built just before WWI that avoided superfiring turrets in various ways for this reason, to spread the turrets out.

3) Construction/engineering

There are also significant construction challenges and complications in making triple turrets. Many navies (British included) had issues early on and avoided them because of this. It also weakens the ships structure because you need a wider barbette = a bigger hole in your deck so something else needs to be stronger to make up for it. There are a lot of complications.

4) Space and accuracy

Early triple turrets were also very cramped and I think in some cases led to issues reloading the middle gun. Another problem is shell interference. The US in particular found their triple turrets very inaccurate because the shells would overtake each-other in flight so close their wakes pushed each-other apart. They solved this eventually by delaying the firing.

Just a few more thoughts for you there

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Vlad

The more turrets you have the more magazines you need. These magazines need armour and so you can't have as much armour protection for other vital parts. Also having more magazines makes the ship more vulnerable to a lucky shot.

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In 1757 Admiral John Byng was shot "pour encourager les autres". Voltaire

Actually, you proved my comment. Most of the battleships designed and built just prior or during WWII had THREE turrets of various size guns. The UK KGV "were desired" to have three triple 16-in gunned turrets, but for several reasons fell back to two quad and one twin 14-in gunned turrets. Even the UK WWI battlecruisers REPULSE and RENOWN had three twin turrets. I agree that the standard during WWI design and construction was for four twin, then triple, main gun turrets (actually started by the USN MICHIGAN class). Prior to WWI, I don't think there was a standard. More "dreadnought" battleships were likely completed with four twin turrets than any other number of turrets.

By the time of WWII, the need for secondary armament and to at least for awhile to fit with-in treaty tonnage limits restrained the number of main guns that could be carried. Plus, "FAST battleships" became more desirable.

Twin turrets were easier to design and produce. When the Dreadnought era began, twins were the only types that were in production, so to speak, and so the designers at first looked for ways to increase the number of turrets. Many layouts were tried, and the problems noted such as complicating the machinery layout because turrets and magazines broke them up and the limited arcs of fire for the midships guns. Two things began to reduce the number of turrets: the larger gun calibers already mentioned and triple turrets. Most countries decided that having two superfiring turrets forward and two aft was the ideal arrangement. But the naval treaties of the '20's and '30's along with ever-increasing fleet speeds demanded ways to save weight. The need to maximize the number of guns while still retaining enough armor and sufficient power for a tactically meaningful speed meant that 3 triples were preferable to 4 twins. It is always a trade off. Three triples = 9 guns, but a disabled turret costs 1/3 of the armament. With 4 twins, only 1/4 of the armament is lost if a turret is disabled, but the price is a larger ship with less starting firepower. The HMS Vanguard, with 4 twin 15" gun turrets was longer than the Lion design with 3 triple 16" turrets because of the fourth turret, even with the lesser gun caliber. The Vanguard design only existed because of the availability of the turrets. Of course, treaties were not the only thing limiting size. Cost and dockyard capability also played a major part in the design process.

Tangent:
Weight of broadside:
#
USN 16" Mk6/7 Iowa, South Dakota, and Washington classes (3 triple)
2700 pound AP Mk8 = 24,300 pounds
1900 pound HC Mk13/14 = 17,100 pounds
#
USN 16" Mk5/8 Colorado class (4 twin) [1938]
2240 pound AP Mk5 = 17,920 pounds
1900 pound HC Mk13/14 = 15,200 pounds
#
USN 16" Mk1 Colorado class as built
2110 16" AP Mk3 = 16,880 pounds

Alaska class
12" Mk8 (3 triple) nine barrels
1140 pound AP Mk18 = 10,260 pounds
940 pound HC Mk17 = 8,460 pounds
#
Wyoming class
12" Mk7 (6 twin) 12 barrels
870 pound AP Mk15 = 10,440 pounds
740 pound HC Mk16 = 8,880 pounds

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The midships turrets often ended up producing such engineering atrocities as putting the P and Q magazines between boiler rooms. In a situation like this, obviously it's a bad thing if the magazines are exposed to the heat and worse, the fire of the boilers. Not only did the provision of additional magazines inherently make the design longer, but the arrangements to keep the magazines safe compounded that problem. This was also logistically problematic for coal burners, where one would prefer to keep the fuel close to the boilers.

I've also come to realize recently just how dangerous a battleship's guns were to herself. It seems that virtually every surface engagement caused blast damage to the firing ship unless the guns just happened to be trained almost directly away from any part of the ship. Ie broadsides were no problem, but if Q or X turret had to bear on a generally forward target (or A/B/Q on a stern target), bad things tended to happen. I would have thought that this was getting worse, rather than better, later in WWII, as radar is both relatively delicate and became instrumental to the fighting capability of the ship.

Many turrets seemed to be OK in the early part of the Dreadnought era, but with the adoption of the all-or-nothing armouring schemes, a design like USS Wyoming that placed four twin turrets aft of the funnels, with the Y guns almost to the fantail would have required a massively greater armored box.

I'd like to see the internal layout of HMS Agincourt - that had to be a designer's nightmare with seven turrets!

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... Brian

HMS Agincourt was a true nightmare. The original intention was to give it the same broadside as a ship armed with 14" guns, with 12" guns.

British 14"/45 Mk2 (4 twin)
APC 1586 pounds Broadside = 12,688 pounds

British 12"/45 Mk13 (7 twin)
APC 859 pounds Broadside = 12,026 pounds

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I think that, aside from considerations of magazines interfering with machinery spaces, an overriding consideration would be arcs of fire.

Obviously, it is better to have all main armament on centerline turrets. Each turret could fire to either side, reducing the number of turrets needed for maximum broadsides.

Wing turrets would only be useful in engagements on their own side. But P and Q turrets would each have to be able to fire on either side. But there effectiveness would be reduced in proportion to the distance from 90deg. to the hull centerline on either side. Blast damage would then be a problem. Also, there would be a problem with gun elevation on these turrets, so as not to interfere with rigging and antennas.

Very little stuff that can be damaged by blast is found on battleships beyond the main turrets. The forward turrets shoot over anchor gear and cables. Aft turrets could be a bit more problematic, as it was possible to wreck ship's aircraft, catapults, and cranes.

I see photos of battleships with aft turrets with guns trained forward alongside the superstructure (to augment the forward turrets), but if they were to have been fired in this position, they would have caused considerable damage to the ship.

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Les Foran
On the Oregon Trail

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Two things related to hull form.

1: Front magazine - care had to be taken to ensure that sufficient space was left between the outer hull and the magazine such that a mine would not directly set-off the propellant.

2: Rear magazine - the hydrodynamic form leading to the propellers/rudder(s) COULD mean that there was a compromise between efficient hull form and distance between outer hull and magazines - this MIGHT limit space available for the side (torpedo) protection system. The USN got around this by using the skegs , the RN had problems with the Vanguard until they lengthened the hull aft of Y-turret.

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Ships arranged like HMS Nelson, with three turrets not all superfiring, could do this too. C turret was normally trained forward, and since it was not superfiring over B, if it had fired in such a position, it would hit the B barbette - and probably destroy itself too. I assume they had physical interlock to prevent this from happening.

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... Brian

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RN ships of the WW2 era, in general, had three sets of stops ;

- One, with the most limited arcs of fire, was for normal useage.

- Another, ones which allowed fire nearer to structures, but which might cause damage (depending upon elevation, etc ....) These stops would only be used at the captains discretion. Only certain ships had these stops.

- Third, permanent stops which stopped guns from rotating into arcs which would cause damage to themselves or to the ship's structure. These were here because there MIGHT be maintenance or other reasons for moving guns to their extremes.

In addition, some guns needed elevation stops at certain bearings.

And, as noted above the Nelsons (and others) needed mechanical gear to stop firing at particular bearings (and indeed elevation).