In assessing collision risk, which statement is true?

• A. If the range to another vessel increases, risk of collision is high.
• B. If the bearing to the other vessel does not change and the range decreases, there is a risk of collision.
• C. If you see the other boat's lights, collision risk is zero.
• D. If the bearing to the other vessel changes rapidly, there is no risk.

Answer: (B)

The main idea is to watch how the other vessel appears to move relative to you. If the bearing to the other vessel stays the same while the range gets shorter, you’re converging on a collision course. In that situation there isn’t time to react after the fact—you must take action now to increase separation or change bearing.

That’s why the statement is the true one: a constant bearing with decreasing range means you and the other vessel are on a collision path, so risk is present and requires immediate adjustment.

Why the other ideas aren’t right: if the range is increasing, you’re moving apart, so collision risk is decreasing, not increasing. Seeing the other boat’s lights does not guarantee safety—you could be on a crossing path, and you still may have limited time to decide. If the bearing changes rapidly, that signals the other vessel is maneuvering; it can create or indicate imminent risk, not negate it, so you shouldn’t assume there’s no risk.