What is the sun-run-sun fix method?

The sun-run-sun fix method is an important navigational technique that aids mariners in determining their position using observations of the sun throughout the day. This method involves taking three separate observations of the sun at different times, ideally spread over several hours. These observations are then combined with the vessel's dead reckoning position to create a "running fix," which helps in pinpointing the ship's location on the water.

By taking the first observation and plotting it on a navigational chart, the navigator can determine the course and distance traveled by the time of the subsequent observations. This continuous tracking allows for adjustments to be made based on the vessel's movement and any changes in the sun's position, leading to a more accurate determination of the current position.

This method is particularly valuable because it utilizes the sun, which is a reliable celestial reference, and it accounts for the vessel's progress over time, enhancing navigational accuracy during daylight hours.