🔍 Key Concepts
• Study how a ram-type electro-hydraulic steering gear works, especially how opposed rams move the tiller for left vs. right rudder.
• Trace the mechanical linkage from the rudder stock and tiller (J) out to the cylinders labeled A, H, and D.
• Remember that one side of the system will be under pressure (driving stroke) while the opposite side is on the relief/return stroke as the rudder moves.
💭 Think About
• When left rudder is ordered, which way must the tiller (and quadrant J) rotate in this plan view, and which cylinders must PUSH versus PULL to make that happen?
• Looking at the piping in the illustration, which ends of cylinders A, H, and D are connected to the pressure side when the power unit driving left rudder is operating?
• For each of A, H, and D, ask: during left rudder, is this cylinder actively forcing movement (pressure) or simply allowing oil to flow back to tank (relieving)?
✅ Before You Answer
• Verify which direction in the drawing corresponds to left rudder by using the FWD arrow and imagining the ship’s stern and rudder position.
• For each labeled cylinder (A, H, D), determine whether its rod is extending or retracting during left rudder and match that to pressure vs. relief.
• Check that your final choice is consistent with all three cylinders’ roles simultaneously; none of them should contradict the actual rotation needed for left rudder.