What range scale is appropriate?

• A. Always 6NM
• B. Usually 24NM
• C. Depends on weather only
• D. Usually 12NM but can vary depending on your situation

Answer: (D)

Range scale on radar is about balancing how far you can see with how clearly you can identify and track targets. The best approach is to start with a practical default and then adjust as conditions change. Usually about 12 nautical miles gives a reasonable trade-off between long-range awareness and detail, but this isn’t fixed. In busy or close-in situations—near ports, in heavy traffic, or when you need precise bearing information—you shorten the range to get more detail and faster updates. In open water with sparse traffic or when you want to watch distant targets or weather, you extend the range for earlier warning. Weather matters, but it isn’t the only driver; your speed, maneuvering needs, and the level of traffic also shape the right choice. So, using a typical 12 NM while remaining flexible to vary the scale according to your situation is the most effective approach.