How do wind and current influence collision avoidance decisions?

• A. They have no effect on collision avoidance.
• B. They affect relative motion and stopping distance, requiring adjustments to speed and course.
• C. They only affect vessel stability, not avoidance.
• D. They determine radio frequencies used for signaling.

Answer: (B)

Wind and current change how your vessel actually moves over the ground, so collision avoidance decisions must account their effects on relative motion and stopping capability. They create drift and alter your track over ground, which can shift the apparent bearing and the calculated closest point of approach with another vessel. They also affect ground speed, so the time and distance needed to stop or maneuver changes with direction of current and wind. In practice, you recalculate your CPA and TCPA using the wind/current vectors and adjust your speed and course to maintain a safe separation, anticipating how the other vessel’s path will be influenced as well. If the current or wind pushes you toward another vessel, you may need to reduce speed, change course earlier, or allow more turning room to stay clear.