Systematic Fog Strategy

When fog descends, you need a systematic plan executed quickly. The priority is to transition from visual navigation to instrument navigation before you lose all references. Every second counts — the quicker you act, the safer you will be.

Step 1 — Fix your position while you can still see landmarks, buoys, or shore features. Take GPS, visual, or radar bearings and plot them on the chart immediately. This is your last known reliable position. Step 2 — Reduce speed to a safe speed under Rule 6. You must be able to stop within the distance of your visibility. Step 3 — Turn on navigation lights regardless of the time of day. Step 4 — Start sounding the appropriate fog signal under Rule 35.

Step 5 — Post a dedicated lookout on the foredeck, listening as well as watching. Brief the crew on their roles: who monitors radar, who monitors depth, who keeps lookout. Step 6 — Begin regular fog signal monitoring — listen for other vessels' signals and try to determine their bearing. Step 7 — Monitor radar and AIS continuously. Plot any contacts and assess CPA. Step 8 — Monitor the echo sounder and compare depths with the chart to confirm your track.

Consider anchoring if you are in shallow water, near a shipping lane, or uncertain of your position. Anchoring removes the risk of collision caused by your own movement and lets you concentrate on monitoring. Sound the correct at-anchor fog signal (bell for 5 seconds every minute). When visibility improves, take a fresh fix before getting under way again.