🔍 Key Concepts

• How to read light characteristics on a nautical chart, especially Gp Fl R (2) 10 sec • Difference between period of the light and range of visibility (e.g., 19M) • What types of information (like radar reflectors or IDs) are normally included in a light’s chart notation

💭 Think About

• Break down each part of the notation: what does Gp Fl, R, (2), 10 sec, 160 ft, and 19M usually mean? • Ask yourself which part of the notation, if any, refers to a distance and which refers to time. • Consider whether charted light descriptions normally include details about radar reflectors, or if those are shown differently on charts.

✅ Before You Answer

• Verify what M stands for in charted light ranges (pay attention to whether it’s miles or another unit). • Confirm that 10 sec refers to a time characteristic (period) and not a distance. • Check how radar reflectors are indicated on charts and whether they are part of the light characteristic string or shown by a separate symbol.