Passage planning for coastal sailors: a seven-step guide

Passage planning means preparing the trip from departure to arrival, then monitoring and revising that plan while underway. A useful plan combines current official charts, local information, weather, tide and current, the boat's limits, the crew and realistic alternatives.

The UK government's port and marine safety guidance notes that passage planning applies to all vessels and that plans should remain flexible as tide, weather, traffic and local circumstances change. The complexity should match the trip: a short harbour transfer and an exposed coastal leg do not need identical paperwork, but both deserve deliberate preparation.

1. Define the trip and its limits

Write down the departure point, intended destination and expected departure and arrival windows. Add the boat's draft, realistic speed, fuel or electrical range and any crew limits that affect the plan. A six-knot estimate is useful only if the boat and conditions can support it.

Agree on the purpose of the trip. A training sail can turn back early; a delivery may create pressure to continue. Naming that pressure makes it easier to resist when the conditions no longer fit the plan.

2. Use current official charts and sailing directions

Choose official charts at suitable scales for the broad route, approaches and harbours. NOAA says nautical charts show shoreline, depths, landmarks and aids to navigation, while electronic navigational charts can support positioning and hazard awareness. NOAA's recreational-boating resources also point to Coast Pilot sailing directions and current chart products for U.S. waters.

Check the chart producer's latest updates and the relevant notices to mariners. A route saved last season may cross information that has changed.

3. Mark hazards, decision points and margins

Identify shallow water, isolated dangers, traffic routes, restricted areas, headlands and harbour constraints. Mark the places where the plan needs a decision: continue, wait, alter course or turn back.

Do not reduce safety to a line drawn down the middle of open water. Consider how much room remains if the wind shifts, visibility falls or the boat cannot hold the expected course. MARLOG's points-of-sail guide shows why the straight-line distance can be a poor estimate for a sailing boat.

4. Build tide and current into the timing

Check water levels and currents for the time the boat will reach each constrained area, not only for departure. Harbour entrances, shoals and narrow channels may have different limits. Compare the prediction with the boat's draft and an appropriate margin.

Current can change both speed over the ground and the track required to reach a destination. Recalculate arrival times when the actual progress differs from the estimate.

5. Read the weather along the whole route

Start with the official marine forecast and warnings. Then compare wind, gusts, visibility, wave height, period and direction at the departure area, exposed legs and destination. A single point forecast is not a route forecast.

Check the return or alternative route as carefully as the outward leg. A favourable wind in one direction can create an upwind return, and conditions may change before the second leg begins.

6. Prepare alternatives and an abort plan

Choose suitable places to wait, shelter or end the passage early. Confirm their charted approaches, operating limits and local information. An alternative harbour that cannot be entered in the expected tide or sea state is not yet an alternative.

Set clear triggers for changing the plan. Examples include arriving late at a tidal gate, visibility falling below an agreed level, a crew member becoming unwell or observed conditions exceeding the limits set before departure. The trigger should lead to an action that the crew understands.

7. Brief, record, monitor and revise

Brief the crew on the route, hazards, expected timing, communications and alternatives. Leave a float plan with someone ashore when appropriate. Record enough of the plan that it can be followed and checked.

Once underway, compare the plan with position, time, weather and the condition of the boat and crew. A passage plan is not finished when the lines are cast off. The UK guidance emphasizes both planning and continuous monitoring because changing circumstances can make the original plan unsuitable.

A compact coastal passage-planning checklist

• Departure, destination and expected timing
• Boat draft, speed, range and crew limits
• Current official charts, sailing directions and notices
• Hazards, traffic, restricted areas and margins
• Tide and current at constrained points
• Official forecast, warnings, waves and visibility
• Alternatives, turn-back points and decision triggers
• Crew briefing, communications and float plan
• Position, time and conditions monitored underway

Where MARLOG fits

MARLOG's Atlas can help you discover coastal places and estimate distance, its Forecast can show marine conditions for selected points, and its Compass can help you think through weather, place and seamanship questions. These are preparation and learning tools.

MARLOG is not a navigation system. Build and execute the route with current official charts, local notices and the equipment required for your waters. Before leaving, complete the boat pre-departure checklist. Get MARLOG for iPhone.

Quick answers

What are the main parts of passage planning? Define the trip, appraise current charts and information, plan the route and timing, identify hazards and alternatives, brief the crew, then monitor progress and revise the plan as conditions change.

Does a short coastal trip need a passage plan? Yes, but the level of detail should match the trip. Even a short passage benefits from checking current charts, local restrictions, weather, tide, boat readiness and a safe alternative.

Can AI make a passage plan for me? AI can help organize questions or explain terms, but it cannot verify the boat, observe local conditions or accept responsibility for navigation. Treat AI output as supporting information and verify it against official, current sources.

Sources: UK Department for Transport, A guide to good practice on port and marine facilities; NOAA, Resources for Recreational Boaters; NOAA, Nautical Charts. MARLOG feature descriptions were checked against its live website on September 24, 2026.