What is the primary purpose of calculating the surge rate?

The primary purpose of calculating the surge rate is to improve speed accuracy when navigating. Surge rate refers to the measurable changes in speed or motion of a vessel in response to different environmental conditions, such as wind, waves, and currents. Understanding and accurately calculating the surge rate allows mariners to adjust their strategies for speed and routing to ensure a vessel is operating effectively and safely.

By accurately gauging a vessel's surge rate, navigators can get a clearer picture of how external factors impact their speed over ground versus speed through the water. This knowledge helps in making informed decisions about travel times, fuel consumption, and overall efficiency during a voyage, leading to more precise navigation and safer operations at sea.