Editing Set and drift (section)

== How to Calculate ==
In order to utilize set and drift in [[navigation]], navigators must first set the course using Dead Reckoning.

A [[Dead reckoning|Dead Reckoning]], DR, is calculated by using a previously determined position on a chart, and advancing that position based on known or estimated speed over a set amount of time. This can be calculated by using the formula Speed = Distance ÷ Time.<ref>{{Cite web|url=http://www.decklicenseprep.com/wp-content/uploads/2014/10/NS-140-Chapter-10-Set-Drift-and-Leeway.pdf|title=Set & Drift and Leeway|last=Deck License Prep}}</ref>

Once an advance position has been plotted, then set and drift can be factored in. If there is a known set and drift, then the corrections can be applied to the Dead Reckoning position to then get an Estimated Position on a chart.

The Course Made Good is the direction in which a ship or vessel has traveled with the effects of current, wind, and helmsmanship. If a current is flowing in the same direction as the ships heading, then the Course Made Good remains the same, but the current speed and ship speed are added together. If the speeds are in opposite directions, then the smaller speed is subtracted from the larger speed. If a vessel runs directly against a current or directly with a current, the speed of the vessel and speed of the current can be added or subtracted from each other. Such as, a vessel has a speed of 8 knots through the water and the vessel is traveling with the current, which is at 2 knots, then the speed over ground is 8+2 and the vessel's true speed is 10 knots.

Set and Drift can be calculated by using a vector diagram and can be drawn and measured on a chart, [[maneuvering board]] or even a plain piece of paper.