In navigation, what must be done at the turn point when setting a reciprocal course?

When setting a reciprocal course, the most essential action to be taken at the turn point is to turn the bezel of your compass 180 degrees. This adjustment allows you to determine the return path, ensuring that you are orienting yourself in the exact opposite direction of your previous course.

The compass bezel is marked with degrees that indicate the direction you are facing; rotating it 180 degrees effectively gives you the new direction to follow back along your route. This is crucial for navigation as it allows divers or boaters to retrace their path accurately without needing to recheck reference points or landmarks. By making this adjustment, navigators can confidently proceed on their reciprocal course while maintaining an awareness of their navigation gear and headings.

The other options, while they may have their use in specific contexts, do not directly relate to the proper method for determining a reciprocal course at the turn point. For instance, simply following a compass on a single heading does not address the need to calculate a return direction. Using visual cues can help in navigation, but relies on peripheral features rather than the fidelity of navigation equipment. Returning to the starting point may seem intuitive, but it is not the procedure for setting a reciprocal course.