What converts linear movement of the ram to radial movement of the rudderpost?

The mechanism that converts linear movement of the ram to radial movement of the rudderpost is typically a crankshaft. In many engineering applications, particularly in marine contexts, a ram may move in a straight line, and that linear movement needs to be translated into rotational or radial motion to operate components like a rudder.

The crankshaft is designed to take this linear force from the ram and pivot it around a fixed point, resulting in the radial motion that is essential for steering systems. This conversion is crucial in providing the necessary directional control for a vessel.

Other components listed, such as a gearbox or gear linkage, may also play roles in mechanical systems, but they do not perform this specific conversion of linear to radial movement. A piston serves a different function, typically relating to pressure changes in fluids or gases rather than directly converting motion in the way described in the question.