Speed-Time-Distance
Speed-Time-Distance ( Go To Top )
It is important to know your estimated time of arrival at a destination, especially if you need to check into a marina or return a charter by a certain time. It also is important in estimating the needed fuel if you are under power. Because of current, the distance traveled is not as accurate as predicting fuel consumption as the amount of time the engine is running at a certain RPM. The time remaining is equal to the distance to be traveled in nautical miles divided by the speed in knots.
Time = Distance / Speed
This equation can be used either for units of statue miles and miles per hour or nautical miles and knots. The most common units used for navigation are nautical miles and knots; however, there are areas such at the Intracoastal Waterway where distance markers are in statue miles. You must be sure what units your charts and aids to navigation are using and be sure to set your knot meter or GPS accordingly.
The other common use of the speed-time-distance formula is to determine a position based upon distance traveled and direction. This is called dead reckoning. The distance traveled is determined by speed multiplied by the time traveled.
Distance = Speed X Time
In times passed, the stars and sun could be used to determine one's position in latitude. Longitude was a problem and the time plus speed traveled equation was used to estimate miles traveled east and west. Thus, the development of an accurate timepiece capable of keeping accurate time while being tilted and jostled at sea was a major navigational milestone.
Go To Speed Time-Distance Calculator
