What does "SOG" stand for in navigation?

The term "SOG" stands for "Speed Over Ground," which is a critical concept in navigation. It refers to the actual speed at which a vessel is moving across the Earth's surface, taking into account all factors, including currents and wind. This measurement is particularly important for mariners as it provides a realistic and accurate representation of the vessel's performance and progress over water.

Understanding SOG allows navigators to make informed decisions regarding routing and timing, especially in environments where currents heavily influence a vessel's path. It differs from speed through the water, which reflects the vessel's speed relative to the water around it, not the ground below. This distinction is essential for effective navigation and efficient voyage planning.