During your oral exam you are asked: while using ECDIS as your primary means of navigation, you notice the displayed position has jumped suddenly by approximately 200 metres with no corresponding alteration of course. What should you do?

A. Accept the new position as correct, since ECDIS is generally more accurate than other methods

B. Switch off the ECDIS alarm for position discrepancy to avoid further distraction

C. Cross-check the position using an independent method (radar ranges/bearings to identifiable objects, visual fixes, or a second GPS source if available), check the GPS signal quality and HDOP/accuracy indicators, and if a genuine position jump (rather than a display glitch) is confirmed, treat it with suspicion and consider the possibility of GPS spoofing or interference, particularly if operating in an area with known reports of such activity

D. Continue without checking, as GPS position jumps are always due to satellite constellation changes and are inconsequential

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