What to do if your calculated distance feels off?

Rechecking Measurements

When you suspect your calculated distance is incorrect, it’s essential to recheck your starting and ending points. This involves verifying the coordinates or landmarks you used as reference points. Make sure you have accurate measurements of your starting and ending points, and that you’ve accounted for any potential errors in your initial readings. A simple mistake in measurement can lead to a significant discrepancy in your calculated distance.

Analyzing Course and Speed

To ensure your course and speed are accurate, replot your route on a map or chart. Check for any potential navigational errors, such as incorrect turns or deviations from your intended course. Also, verify your speed and time using multiple sources, such as GPS, watches, and log entries. A speed of 4 knots over a 3-hour period should translate to a distance of approximately 12 nautical miles, but this can vary depending on environmental factors like currents and wind.

Dead Reckoning Techniques

Dead reckoning, a technique used in navigation, involves tracking your movement from a known starting point using your speed and time. To enhance the accuracy of dead reckoning, use the “three-sources method.” This involves verifying your speed and time using at least three separate sources, such as a GPS, a watch, and a log entry. Additionally, consider using a chart or map with a grid system to plot your course and estimate your distance traveled.