Which tool is used to determine Ship's Speed or Distance?

The Ship's Log is a critical tool used in maritime navigation to track the speed and distance traveled by a vessel. As ships move through water, the log records this information over time, allowing for an accurate understanding of the ship's progress on its journey. The log can include measured distances based on time and speed, often taking into account various factors such as currents and wind, which can affect the vessel's actual path and speed over ground.

In traditional maritime practices, the ship's logbook would document observations from the ship's speed through the water as well as the distance covered during specific time intervals. More modern systems may integrate technology that assists in calculating these metrics, but the purpose remains the same: to provide navigators with essential data for safe and efficient route planning and navigation. This makes it the most suitable answer for determining a ship's speed or distance traveled compared to the other options listed.