Module 15 - Restricted Visibility
Using Instruments in Fog
Without visual references, you must rely on instruments. GPS provides your position — plot it on the chart regularly. The echo sounder gives depth — compare it with the chart to confirm you are where you think you are. Following a depth contour can guide you along a safe route.
Radar, if fitted, can detect other vessels, land, and large buoys. AIS shows other vessels with transponders. Even without these, a handheld GPS and a depth sounder are invaluable. Keep your compass lit and visible.
- GPS: plot position on chart regularly
- Echo sounder: compare depth with chart as a position check
- Radar / AIS: detect other vessels and land if available
- Follow depth contours for safe navigation
- Keep compass lit and visible
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This public lesson is part of Revision Module 15. Full revision access adds the guided Learn, Practise and Test flow, flashcards and revision progress.