WATER
AWARENESS Tide is the vertical change in water level caused by the gravitational attraction of the sun and moon. These heavenly bodies pull the earth’s water into a bulge. As any location on earth rotates under this bulge, the sea level rises; as that location moves out from under the bulge, sea level falls. There are two high and two low tides each day on the East and West Coasts of the U.S. and only one each per day in the Gulf of Mexico.
Current is horizontal movement of water. In coastal areas, current is caused by the rise and fall of the tide. Current is also caused by gravity (as in river flow), wind, and ocean circulation patterns. This water movement can either assist or hinder your progress when sailing. A wise sailor will utilize favorable currents and avoid adverse ones.
Wind and current flowing in opposite directions can create uncomfortable waves that are short, steep, and closely spaced. When wind and current are flowing in the same direction, the water surface will be much smoother and calmer.
With tide and current prediction apps or tables, you can anticipate the depth and movement of the water where you will be sailing or anchoring.
93 Table of Contents
Non-Adjusted Course This boat aimed directly for its destination but was carried downstream by the current.
COMPENSATING FOR CURRENT When sailing across a current you can compensate for its effect. Instead of steering directly toward your goal, steer for a point upcurrent, and let the current carry you back to your desired course.
Adjusted Course This boat has compensated for the current by aiming upcurrent of its destination and is carried to its destination.
CURRENT
CURRENT
boat heading
actual path
boat heading
actual path
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