What is the practical value of taking a 'running fix' using two position lines obtained at different times, transferred forward along the DR track?

A. It has no real value now that GNSS is universally available

B. It allows a usable position fix from a single navigational aid observed twice (e.g. one visual bearing at two different times, or radar range/bearing to a single object) when a simultaneous two-line fix isn't available — the accuracy depends on the reliability of the DR run between the two observations, so it is less precise than a true simultaneous fix but still valuable, including as a GNSS-independent cross-check

C. It is only usable with celestial observations, never with visual or radar bearings

D. It replaces the need for dead reckoning entirely

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