Another battleship question: four-gun turrets as opposed to three

Prince of Wales, for example had four-gun turrets. Most others had three. Bismark, I think had two.

I’m guessing that for some reason, four-gun turrets turned out to be impractical, “but it seemed a good idea at the time.” What were the details?

I think 2-gun turrets were a bit more common than 3 on battleships.

The advantage of 4-gun turrets was a savings in weight. The disadvantage was a loss of efficiency with all those guns and their crews crammed into one turret.

Someone will be along with better answers, but here’s an article on the King George V class battleships.

The USN debated this while deciding on specifications for the BB’s. In a turret of a certain size, you could have four 14-inch or three 16-inch guns. The 16’s won out. Someone decided that the better performance in range and weight of shot was preferable to the greater number of shots. The French battleship Richilieu had four-gun turrets that were each fabricated from two 2-gun turrets.

Yeah, as others have said, it’s a matter of juggling the issues of weight, space, and cost in the design of these ships.

They allowed for more space for other things w/ fewer (bigger) turrets, such as room for extra boilers (and fuel and crew spaces). The French put a bulkhead down the middle of their 4 gun turrets so if one side was knocked out the other side could keep firing-this actually happened during one battle. But it’s fairly easy to jam the turret gears with a hit, immobolizing the turret. I think 3 guns/turret provides the best tradeoffs between these things, which is the conclusion that the US ultimately came to.

The largest, most heavily-gunned battleships ever actually built, the Japanese Yamato & Musashi, had 3-gun turrets, with 18,1" (46cm) guns.

The planned successor A-150 class battleships were also designed with 3 turrets, but containing only 2 guns (20", 50cm). Probably all they could fit in a turret.

Pardon the stupid question, but in a turret, do all guns shoot at once, or do they take turns, so that one is shooting while others are reloading? Or is it a combination?

The guns are independent, so they can all shoot together or at different times. (They can even aim at different points.) Normally, the first time they fire, it is all together or in close succession. After that, it depends on the reloading speed. Each gun has it’s own crew, and some are faster at reloading than others. Generally, each gun fires as soon as it is reloaded & ready, without waiting for the other guns. A rapid rate of fire was very important in battleship fights.

It’s a little more complicated. Some turrets are 3-gun mounts and others are Triple mounts. The difference is that in a triple mount, all the guns are locked together on one elevating mechanism and can only elevate or depress together. In a 3-gun mount, each gun is able to elevate and depress independently. Triple mounts I think were gone before WWII.

Also, there is often a delay inserted in the middle gun on a group of three. This is because the muzzle blasts from the guns can interfere with each other and affect the trajectory. On double and 2-gun turrets this usually isn’t done. When firing a gun that is not along the centerline of a turret, the recoil tries to rotate the turret and this affects the trajectory. More so than the muzzle blast interference. So the two outer guns on a triple or three-gun turret are fired together while the middle gun has a slight delay. Two-gun and double turrets fire together.

A number of other issues not considered so far:

At battleship combat ranges (tens of thousands of yards), the targets move substantially between shot and fall of shot. Firing sequentially allows spotting of the fall of individual shots, which allows refinement of aim.

Firing simultaneously places a lot of strain on the hull and turret mounts; sequential fire extends life of systems, and reduces cost of maintenance.

In my experience, a ‘full broadside’ is one gun from each mount firing simultaneously or in very short sequence. With the Iowa-class ships, at rapid fire, that allows coordinated 3-shell salvos to arrive on-target every ten seconds.

There is more to naval gunnery than just shell diameter. Range, reload rate, tube elevation and traverse rate, whether or not the guns could be reloaded whilst elevated (continuous training on-target)) aerodynamics of the shells, armor-piercing design (complex subject!), shell weight, and sectional density all played their role.

Almost, but you’re getting terminology confused.

In a mount, all of the individual guns elevate together. As an example, the 5"/38 mountcommon to nearly every US naval ship in WW2. The elevating mechanism raises or lowers both guns at the same time. Obviously, both guns are trained together, dictated by the rotation of the mount itself.

In a turret, each gun has its own elevating mechanism, and can elevate seperately from the other guns. The 16"/50 of the Iowa class are prime examples. There is a photo on Wikiof the Iowa just after the turret 2 explosion in 1989, look at turret 1 - two guns are down, one is up - a feature of seperate elevating mechanisms. I don’t know if the center gun of turret 2 dropped after the explosion, or if it was like that to start. Again, as with a mount, all of the guns are trained to the same direction, a function of rotating the turret.

My grandfather (a USN Gunner’s mate) drilled that into me from a very young age.

POW was a treaty battleship, to get what the RN wanted, they had to get creative with how they laid out the ship.

Kinda depends on what you do with the ship. If you want to pound offshore sites then 3 works fine. Putting 2 sets of 4 up front puts 8 forward shots against another ship.

If you were talking about the KGV and its class, they had a quad turret in the front and a quad in the stern, and a double above and behind the forward quad, so it would work out six 14 inch for the RN versus six sixteen inch for the USN.



The French used the double quad forward design-the British used 3 forward triples in the Nelsons (the most hideous-looking BB’s ever). Like I said it’s all about tradeoffs-note that these turrets could typically rotate close to or in excess of 270 degrees, so that even the rear ones could often fire into the forward 180 arc of the ship.

Just have to share this photo, a favorite of mine. Check out the water:

I think HMS Nelson was kinda cool-looking, myself:

It’s worth noting that a primary design consideration for US ships in the period under discussion was, “it has to fit through the Panama Canal.” So the turret size had a technical upper limitation.

Rodney and Nelson boasted unusually high elevation of their main battery. I think it was originally conceived as an advantage to send plunging fire through thinner deck armor. But at least once, this feature was used to fire the main guns at aircraft.

Yup. This is why the Iowa class has such fine lines, IIRC. (Need the length for bouyancy.)

Were not the 18" guns the limit? I can see a law of diminishing returns-larger diameters mean haevier shell casings, requiring more propellent charge, etc. I understand that the USN’s 16" guns were about eaqual to the Yamato’s 18" guns, in terms of penetrating power.