Why is it important to preserve night vision on the bridge during hours of darkness (e.g. using red lighting, dimming displays)?

A. It has no real effect on a watchkeeper's ability to see outside

B. Red lighting is used purely for aesthetic/atmosphere reasons

C. Bright white light or overly bright displays cause the eyes to adapt to that brightness, reducing the ability to detect dim lights, shapes, or other vessels outside in the dark — red lighting and dimmed displays help maintain dark adaptation so the watchkeeper can see external lights and contacts more effectively

D. Night vision preservation is only relevant for vessels without radar

A. The tidal height at the time of transit to confirm sufficient under-keel clearance

B. The yacht's fuel consumption for that leg

C. The colour of the seabed shown on the chart

D. Only the distance to the next waypoint

A. Switch the ECDIS to standby mode and navigate by GPS position alone

B. Ignore it — ECDIS alarms are frequently false and can be left running

C. Assess the situation against the planned route and charted depths, take action to maintain safe water, and inform the Master if there is any doubt

D. Acknowledge and silence the alarm immediately so it does not distract the helmsman