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)  »

avg

(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.

wol

manish-mayank