Coastal Skipper and Yachtmaster Quiz · Tidal calculations
Read the factor from this tidal curve at the gold marker, 2 hours before high water. What is the height of tide at that time?
A tidal curve drawn as a factor from 0 at low water to 1.0 at high water, on a grid with a line every quarter (0, 0.25, 0.50, 0.75, 1.0) and every hour from 6 hours before to 6 hours after high water. A gold marker with a question mark sits on the rising curve 2 hours before high water. Caption: today, low water 1.2 m, high water 5.2 m.
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4.2 m. The curve gives a factor of 0.75 at 2 hours before high water. Height of tide is low water plus the factor times the range: the range is 5.2 minus 1.2, which is 4.0 m, so 1.2 plus 0.75 times 4.0 is 4.2 m. Forgetting to add the low water height is the usual slip.
