Terrestrial and Coastal Navigation, Position Fixing, Passage Planning and Chartwork
Domain 1 tests whether you can turn observations into a reliable fix, plot it correctly, and convert a planned route into a safe, monitored passage. Expect practical chartwork and clear reasoning rather than memorised definitions.
Position fixing and bearings
Convert compass to true using CDMVT: Compass ± Deviation = Magnetic; Magnetic ± Variation = True. Easterly error is added when going from compass to true; westerly error is subtracted. Fixes come from visual bearings, transits, horizontal angles, ranges and running fixes. A running fix advances an earlier line of position by course and distance, allowing for current where known.
Passage planning
Plan berth to berth: appraisal, planning, execution and monitoring, consistent with IMO Resolution A.893(21). Mark no-go areas, abort points, wheel-over positions, under-keel clearance, tide windows and contingency anchorages. A plan is not complete until it has been checked and briefed to the bridge team.
Worked example
Compass bearing 045°, deviation 3°E, variation 5°W. Magnetic = 045 + 3 = 048°. True = 048 − 5 = 043°. If the echo sounder reads 12.4 m and draft is 6.2 m, static under-keel clearance is 6.2 m before allowing for squat, swell and tide.
Traps
Applying variation before deviation; ignoring gyro error; treating soundings as depth below keel rather than chart datum; confusing set (direction toward which the current flows) with drift (its speed); plotting a fix without checking the chart datum; producing a waypoint list without under-keel clearance or contingency planning.