Why were quadruple turrets only used on 3 ship classes when they were so weight saving? Actually, why didn't every country strive for the maximum possible guns per turret for weight saving measures?

by Pashahlis
thefourthmaninaboat

One key reason for this is reliability issues. Turrets work best when the ring is a reasonably precise circle. However, the forces that act on a ship at sea tend to distort the turret ring; sagging (where the ship's ends are supported by waves, but the midships is not) or hogging (where the centre of the ship is supported, but the ends are not), make the ship flex and bend. The effects of these forces on a turret ring depend on the size of that ring. A smaller ring will be distorted to a lesser extent, a larger one to a greater extent. As quadruple turrets have the largest rings, these distortions affect them the most. The British 14in Mark III turret, as used on the King George V class, suffered greatly from these issues. The French turrets, meanwhile, suffered from accuracy issues. The guns were placed close together, to reduce the turret diameter. As a result, the shells, and their slipstreams, interfered in flight. However, this was an easier problem to solve than those of the KGVs - fitting delay coils, to delay the firing of each gun in the turret by a few milliseconds, helped reduce the issues.

There are other design issues at stake as well. Quadruple turrets have a large turret diameter; this in turn implies a broad ship. The Richelieus had a beam of 33.08 m, the Iowas, which displaced more and used larger guns, had a beam of 32.97 m. This may seem like a small difference, but it is significant. Larger ships require larger infrastructure, which may not be available. The locks on the Panama Canal in particular place limitations on the beam of any ship that needs to pass through them. Triple turrets also allow for more firepower on the same displacement; three triple turrets give an extra gun for much the same displacement, and make it easier to fit larger guns. Quadruple turrets also have an element of risk. A penetrating hit to a quadruple turret will knock out a greater proportion of the ship's armament than a hit on a triple or twin turret. This can be mitigated against - the French quadruple turrets were essentially two twin turrets stuck together - but this means adding more weight to the turret, reducing the amount of weight saved.