Dead Reckoning (DR) and Estimated Position (EP)

Dead Reckoning (DR) is the process of estimating your position based solely on your course steered and distance run through the water — without accounting for tidal stream or leeway. It gives a basic 'where we should be' position.

An Estimated Position (EP) improves on DR by adding the effect of the tidal stream (set and drift) and an estimate of leeway (sideways drift caused by wind). The EP is more accurate than a DR position. On the chart, a DR position is marked with a cross and 'DR', an EP is marked with a triangle and the time.