Ocean Cpa Method.pdf Apr 2026

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

Uses radio waves to track the relative bearing and range of nearby targets.

Incorporating Rate of Turn (ROT) and Change of Speed (COS) into AIS-based predictions for more accurate results during maneuvers. Ocean CPA method.pdf

The time remaining until the ships reach that minimum distance. 3. Data Inputs

Modern "Ocean CPA" calculations typically integrate data from two primary systems: Defining a "safe zone" around a ship rather

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

More details on reliability in CPA calculations The time remaining until the ships reach that

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: