Estimated Position (EP) - use this when you want to find out where you are, after having travelled from a previously known position (fix). It takes account of tide, and leeway due to wind.
Estimated Position Process handout
Click here for Estimated Position Worked Example EP example
A Predicted Estimated Position is plotted to find where you will travel on a known course, ie will your track clear any danger, or where and when you will intercept a desired position.
Dead Reckoning (DR) - is the simple form of Estimated Position, without using the tide or leeway.
Leeway is estimated by comparing the centre line of the boat with the wake:
If you need to find distance, time or speed use the 'Distance / Speed / Time' circle:
Cover the required value and the circle gives the equation for that value.
eg Distance = Speed x Time