Quote:
Originally Posted by alctel
I'd say the strong currents make one MORE useful. Improves the reading for true wind speed, helps work out current direction/speed and helps with sail trim tweaking
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I rely on the log. Adding to Alctel:
1. Say you're on a close hauled tack trying to make it around a headland.
Comparing SOG with log speed through water gives understanding of the current direction/speed. Good to assess whether the current is pushing you into the headland or away from the headland.
Assessments of current set on
charts or
cruising guides may not be detailed or might change locally of with the conditions of the day.
2. Also, a trip plan, or TR (Trip Report) to a
Marine safety authority will require an ETA at
destination, which requires an understanding of current, and whether the current is behaving as predicted. Our waters are affected by 5 to 7 knots of tide at times. Getting the current wrong and not realising it can add many hours to an 8 hour trip, meaning arrival after dark or getting caught in the next bad
weather front.
3. Speed through water is a better assessment of how well you are sailing. SOG isn't, because of current assistance.