IMO Resolution A.893(21) defines passage planning as a continuous process in four stages.
1. Appraisal
Gather all information relevant to the voyage: charts and publications, Notices to Mariners, tide and current data, weather routing, draught and under-keel clearance, port requirements, and bunker calculations.
2. Planning
Lay the intended track berth-to-berth on the largest scale charts. Mark waypoints, wheel-over positions, parallel index lines, no-go areas, and abort points. Record contingency anchorages.
3. Execution
Carry out the plan with due regard to changing conditions. The plan is a guide, not a straitjacket — deviations are made on the Master's authority and logged.
4. Monitoring
Continuously verify position by all available means. Cross-check ECDIS with visual and radar fixes. Fix intervals must reflect the proximity of danger, not the convenience of the watch.
Good practice
Brief the full bridge team before departure. Every officer should be able to state the next three waypoints, the next chart, and the nearest safe water at any moment.