While going astern to take the way off close to a berth, the stern swings further toward the berth than expected due to transverse thrust, closing the gap with a moored vessel faster than planned. What is the immediate priority for the OOW conning the vessel?

A. Continue the planned manoeuvre exactly as briefed, trusting that transverse thrust will reverse itself naturally

B. Immediately stop all engine movements and rudder input and wait for the vessel to settle on its own

C. Only the Master can take corrective action; the OOW must wait for explicit instruction before adjusting anything

D. Take immediate corrective action using whatever combination of rudder, engine, and (if available) bow/stern thruster or tug assistance is most effective for the specific situation, while clearly communicating the developing situation to the bridge team and considering early use of an anchor or tug if control cannot be regained quickly — do not wait to see if the swing self-corrects

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