What does the 3-minute rule help determine in terms of distance traveled?

The three-minute rule is a practical method used by mariners to estimate distance traveled over ground based on speed. It states that if a vessel is moving at a speed measured in knots, you can calculate the distance traveled in nautical miles over a time span of three minutes by multiplying the speed in knots by 100.

For example, if a vessel is moving at a speed of 10 knots, applying the three-minute rule gives a distance of 10 knots * 100 = 100 nautical miles over a three-minute period. This simplification is helpful for quick calculations while navigating.

This method is particularly effective because it leverages the direct relationship between speed, time, and distance, allowing mariners to quickly estimate how far they have traveled in a short amount of time. It's a valuable tool when making navigational decisions on the water.