Weather strategy for a coastal passage

A weather window is a period in which the expected wind, sea state, visibility and hazards fit the vessel, route and crew. Define those limits before looking for a favourable forecast: consider wind against tide, exposed headlands, harbour-entry constraints, daylight, crew experience, seasickness, fatigue and the consequences if the forecast is wrong.

Use the latest appropriate official marine forecasts and note each issue time, validity period and geographic area. Compare the Shipping Forecast, Inshore Waters Forecast, current coastal observations, pressure trend, NAVTEX or other maritime safety information available for the route. Different apps may be presenting the same underlying model, so apparent agreement is not necessarily independent confirmation. Look for uncertainty, timing differences and conditions that would invalidate the plan.

During the passage, compare observations with the forecast: pressure tendency, cloud development, visibility, wind direction and force, sea state and actual progress. A falling pressure trend is evidence to interpret with the wider weather picture, not a universal stand-alone threshold. Set review points and decision triggers in advance, such as reefing before an exposed leg, turning back before a tidal gate or diverting while a safe harbour remains reachable.

Waiting, shortening the route or diverting is a normal passage-planning decision. The plan should name bolt holes, their entry constraints, the latest safe decision time and who receives updated intentions. Once committed, continue to monitor and be ready to reef early, reduce exposure, alter destination or use an appropriate heavy-weather tactic. The controlling questions are whether the destination and alternatives remain safely reachable and whether the crew retains enough capacity for the next stage.