Dead Reckoning

Dead reckoning (DR) is the navigation practice of estimating a vessel’s present position from a known fix by applying course steered, speed through the water, elapsed time, and expected leeway or current. The resulting DR position is an informed plot, not a confirmed fix, and should be regularly checked against observations or electronic navigation.

For boaters, DR is a core safety skill because it maintains situational awareness if electronics fail, satellite reception is poor, or chartplotter data is suspect. Comparing DR with GPS fixes helps reveal drift, steering error, or instrument issues, while accurate Compass courses and allowance for Tidal Current improve the reliability of the plot.

PredictWind tools support modern navigation by showing forecast wind, waves, tides, routing and position history, but DR remains a valuable backup and cross-check. GPS tracking through DataHub can preserve an actual track for comparison with logbook DR positions during coastal or offshore passages.