Your ARPA has automatic speed inputs from the log. Due to currents, the log is indicating a faster speed than the speed over the ground. What should you expect under these circumstances?

Correct Answer: Option D — The targets true course vector will be in error.

ARPA calculates true vectors by combining own-ship's speed and heading with relative target motion. If the speed input is erroneous due to current, the vector triangle is distorted. Per Bowditch, this error propagates into the target's true course and speed calculation, rendering the displayed true vector inaccurate for collision avoidance.