The process of firing one of the massive 16-inch guns on an Iowa-class battleship was a highly coordinated and intricate procedure that involved a combination of mechanical systems, crew training, and advanced fire control technology for its time. Here's an overview of how a single gun on the turret of an Iowa-class battleship, such as the USS Iowa, was fired:
Gun Turret Configuration
Each Iowa-class battleship had three main gun turrets, designated as Turret 1, Turret 2, and Turret 3. Each turret housed three 16-inch/50 caliber Mark 7 guns, but each gun was independent in operation, meaning any one of the three could be fired without affecting the others.
The turrets themselves were engineering marvels, extending deep into the ship's hull, with only the visible gun barrels and part of the armored turret above deck. They were heavily armored and designed to withstand significant punishment in combat.
Loading and Preparation
Ammunition Handling
Each 16-inch gun fired projectiles weighing between 1,900 and 2,700 pounds, depending on the type of shell (high-explosive or armor-piercing).
The shell was hoisted from the ship's magazines deep below the turret using an elaborate elevator system.
Powder Charges
To fire the shell, the gun used six silk bags of powder, each weighing about 110 pounds, for a total of approximately 660 pounds of propellant per shot. These were also transported to the gun using the turret's internal handling systems.
Gun Elevation and Training
The gun's angle of elevation and the turret's rotation were adjusted using hydraulic or electric systems, controlled by the ship's advanced Mark 8 fire control computer or manually by the turret crew.
Fire control data, including target range, wind conditions, and shell type, was calculated and fed into the gun’s targeting system to ensure accuracy.
Breech Loading
The gun's breech mechanism, a massive steel block, was opened hydraulically. The shell was loaded first, followed by the powder charges. The breech was then sealed to prepare for firing.
The Firing Process
Command to Fire
Orders to fire came from the fire control center or the ship’s commanding officer. The target data was fed into the fire control system, and the firing solution was communicated to the turret crew.
Firing Mechanism
A single gun could be fired by activating its electric primer, located at the breech. This primer ignited the powder charges, creating an explosive force that propelled the shell out of the barrel at speeds exceeding 2,500 feet per second.
Recoil and Re-Preparation
The gun's immense recoil, which pushed the barrel back several feet into the turret, was absorbed by a hydraulic recoil system.
After firing, the barrel was swabbed and cleaned to prepare for the next round.
Coordination and Crew Effort
Each turret required a crew of 77 to 110 sailors, working in shifts across multiple decks to manage ammunition handling, loading, and aiming. Firing a single gun was a monumental task, but it could be executed in under a minute due to the crew's training and precision.