You are OOW approaching a pilot station and your primary GPS position suddenly jumps 0.3nm from your plotted DR track with no warning alarm. What should you do?

A. Trust the new GPS position immediately and alter course to match it, since GPS is more accurate than DR

B. Treat the jump with suspicion: cross-check the GPS position against radar ranges/bearings to charted objects, your DR/EP, and if fitted, a second independent GNSS receiver, before acting on it — an unexplained jump with no fault alarm can still indicate a genuine error, and blind trust in a single source is the underlying risk

C. Switch off the GPS entirely and navigate by DR alone for the rest of the passage

D. Report it to the company only, with no immediate on-board verification needed

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