🔍 Key Concepts

• ARPA (Automatic Radar Plotting Aid) guard zones – difference between inner and outer zones • How an inner guard zone helps prevent close‑quarters surprises near your own ship • Which option describes a function that is unique to the inner zone rather than the outer zone

💭 Think About

• Which option best describes a warning about targets that appear very close to own ship without prior tracking? • Does the inner guard zone mainly help with approach to CPA limits, or does it deal with objects that are already inside or just popping up near you? • Think about small, weak targets: would they more likely first appear in the outer zone or only be seen when they are already close in?

✅ Before You Answer

• Identify which choices describe something that could be done by either guard zone (not unique to the inner one). • Check which option specifically mentions targets that are first detected or initially detected within the inner area. • Verify which option is about preventing sudden close-range threats rather than general early warning at longer range.