Where is a vessel's pivot point typically located when making headway, and how does this change when making sternway?

A. The pivot point is always exactly at the vessel's midpoint regardless of whether making headway or sternway

B. The pivot point is a fixed physical point marked on the hull, unrelated to the vessel's motion

C. Making headway, the pivot point is typically around one-third of the vessel's length from the bow; making sternway, it shifts toward the stern, typically around one-third of the length from the stern — this shift changes how the bow and stern swing during turning manoeuvres in each direction

D. The pivot point only exists for twin-screw vessels, not single-screw vessels

A. The propeller blades on one side of the shaft work in deeper, less disturbed water than the blades on the other side, and this asymmetric loading, combined with the angle of the propeller race against the hull, produces a sideways force on the stern — for a right-handed propeller, this characteristically pushes the stern to starboard when going ahead and to port when going astern

B. It is caused entirely by wind acting on the superstructure, unrelated to the propeller

C. It is caused by rudder angle alone and disappears completely if the rudder is centred

D. It only occurs on twin-screw vessels and is not present on single-screw vessels

A. The difference is due only to engine RPM differences between ahead and astern settings

B. Going astern, there is no rudder effect to counteract the transverse thrust (since the rudder has little or no effect on a sternway-making vessel at low speed, especially with the engine going astern), so the sideways push of the propeller dominates the vessel's behaviour, whereas going ahead the rudder is normally effective and can counter or mask the transverse thrust

C. Transverse thrust does not exist when going astern under any circumstances

D. Transverse thrust is actually stronger when going ahead, not astern, and the question premise is reversed