How to calculate Rate of turn or ROT / wheel over point ?

In order to make sure the vessel hits its planned course track after a major course alteration, it is adviseable to calculate and plan the turn in advance. This is especially valid for larger vessels. With this method a safe and controlled turn can be carried out.

This method requires that the vessel is equipped with a Rate of Turn indicator.

The Rate Of Turn can be found with this approximate formulae: ROT (⁰/min)  »

(The ROT is measured in “degrees per minute” )

 EXAMPLE: 

1. Select the turn radius. (In this example: 1 nautical mile)
2. Construct the turn in the charts with the selected turn radius to find the Centre Of turn.
3. A line drawn from the Centre Of Turn and 90⁰  down to the initial course track marks the Actual Start Of Turn.
4. The position of the Wheel Over Line is generally, for larger vessels, about 1-2 cables before the Actual Start Of Turn The Wheel Over Line should be drawn parallel to final planned course track.