What assists in turning the rudder aboard a ship?

The mechanism that assists in turning the rudder aboard a ship is the RAM actuator. A RAM actuator is a type of hydraulic actuator that converts hydraulic pressure into linear motion, which is crucial for moving the rudder. When the ship's control system sends a signal to the actuator, it uses hydraulic fluid to push or pull a piston, effectively turning the rudder in the desired direction. This provides the necessary force and precision to control the ship's steering effectively.

In the context of ship operation, the RAM actuator is essential for maneuverability, especially in tight spaces or during complicated navigational situations. It plays a significant role in ensuring the vessel can respond quickly to commands, thus enhancing safety and control.

The other options, while they might relate to ship operations, do not specifically assist in turning the rudder itself. For instance, vacuum pumps are typically used in systems requiring suction, not for steering mechanisms. Electronic throttle control refers to the management of engine output rather than directly influencing rudder movement. Hydraulic lines provide the medium for fluid transmission but do not perform the function of actuating the rudder themselves. The combination of hydraulic lines and the RAM actuator, however, works together in the steering system to accomplish effective rudder movement.