CPA

CPA (Closest Point of Approach) is the predicted minimum distance between your vessel and another vessel if both continue on their present course and speed. It is normally shown with TCPA, the time until that closest point is reached, giving a quick measure of collision risk.

For skippers, CPA is a decision-making tool, not a substitute for a proper lookout. A small CPA in a busy channel, poor visibility or a shipping lane may require an early alteration of course or speed. CPA calculations are commonly derived from AIS, Radar and a Chartplotter, then checked against visual bearings and the COLREGs.

On passages, monitoring CPA alongside weather, tide and route information helps maintain safe separation while avoiding unnecessary manoeuvres. PredictWind users can view onboard traffic data through connected systems such as DataHub, combining navigation awareness with forecasts, routing and GPS tracking for a clearer operational picture.