Radar aids in early risk assessment by providing what information to support collision avoidance?

• A. Vessel color and lighting.
• B. Exact vessel name.
• C. Weather forecast for the next day.
• D. Relative motion information, including range and bearing to targets, to assess collision risk.

Answer: (D)

Radar helps you gauge collision risk by giving relative motion information about other vessels. It shows how far away a target is (range) and where it is relative to your own heading (bearing), plus how those values change over time. By watching the rate of closure and the trend in bearing, you can infer the other vessel’s speed and direction relative to you, estimate the closest point of approach and the time to that point, and decide early on whether action is needed to avoid a collision.

Other options don’t provide this essential situational data: color and lighting aren’t obtained from radar; the exact vessel name isn’t something radar routinely displays; and weather forecast information isn’t radar data.