To determine the Speed Over Ground (SOG), which two pieces of information are required?

To determine the Speed Over Ground (SOG), which two pieces of information are required?

• A. Course and Wind Direction
• B. Estimated Time of Arrival (ETA) and Distance
• C. Estimated Time of Departure (ETD) and Estimated Time of Arrival (ETA)
• D. Current Speed and Heading

Answer: (C)

To determine the Speed Over Ground (SOG), the primary requirement is the distance traveled and the time taken to cover that distance. The correct answer involves using the Estimated Time of Departure (ETD) and the Estimated Time of Arrival (ETA), as these provide the temporal boundaries within which the vessel operates. By knowing both the ETD and ETA, one can calculate the total time of the voyage. Coupled with the distance traveled, this information enables the calculation of SOG using the formula SOG = Distance / Time. This is essential for navigational accuracy and safety because SOG directly reflects the vessel's actual speed over the earth's surface, which is critical for effective navigation, especially in conjunction with tides and currents. The other choices do not directly provide the necessary data to calculate SOG accurately. While current speed and heading might inform a vessel's movement, they do not give the total distance or total time required for the SOG calculation. Similarly, knowing wind direction and course or just distances without the corresponding times does not facilitate the correct calculation of SOG directly. Understanding this relationship between distance and time is vital for navigation practices.

To determine the Speed Over Ground (SOG), the primary requirement is the distance traveled and the time taken to cover that distance. The correct answer involves using the Estimated Time of Departure (ETD) and the Estimated Time of Arrival (ETA), as these provide the temporal boundaries within which the vessel operates.

By knowing both the ETD and ETA, one can calculate the total time of the voyage. Coupled with the distance traveled, this information enables the calculation of SOG using the formula SOG = Distance / Time. This is essential for navigational accuracy and safety because SOG directly reflects the vessel's actual speed over the earth's surface, which is critical for effective navigation, especially in conjunction with tides and currents.

The other choices do not directly provide the necessary data to calculate SOG accurately. While current speed and heading might inform a vessel's movement, they do not give the total distance or total time required for the SOG calculation. Similarly, knowing wind direction and course or just distances without the corresponding times does not facilitate the correct calculation of SOG directly. Understanding this relationship between distance and time is vital for navigation practices.