Ocean Cpa Method.pdf -

): The vector difference between the own ship’s velocity and the target's velocity.

The minimum distance (usually in nautical miles) between the vessels at the moment of closest approach. Ocean CPA method.pdf

Provides GPS-based data including SOG (Speed Over Ground) and COG (Course Over Ground). 4. Calculation Methodology ): The vector difference between the own ship’s

The direction of the target's movement relative to the own ship. a collision is possible

The perpendicular distance from the own ship to the target's relative motion line. 5. Advanced Refinements

Defining a "safe zone" around a ship rather than a single point.

The is the estimated position where the distance between two ships (the "own ship" and a "target vessel") reaches its absolute minimum. It is the primary metric used by Watchkeeping Officers to assess the Risk of Collision (ROC) . If the CPA is too small, a collision is possible, requiring immediate maneuvering according to COLREGs . 2. Core Parameters The method relies on two primary mathematical outputs: