🔍 Key Concepts

• Difference between a fix and an estimated/derived position • How course and speed over time can be used to project a position from a last known point • Common plotting terms: running fix, dead reckoning, and estimated/probable position

💭 Think About

• Ask yourself: if you only know your last exact position, your course, and your speed, what are you actually calculating on the chart? • Consider which option(s) involve additional information like bearings or lines of position, and which one relies solely on your own vessel’s motion. • Think about which term is used for a position that is purely calculated, not confirmed by observations or electronic fixes.

✅ Before You Answer

• Identify which choices require at least two lines of position (LOPs) or other observations. • Check which term describes a position that is not based on any new external observation, only on time, course, and speed from a previous known point. • Verify that the term you pick is the one traditionally marked and advanced on the chart at regular intervals along the vessel’s intended track.