NEW !!!!!!!! RYA BASIC SAFETY AND NAVIGATION COURSE
Tidal Theory
Tides (rise and fall) are caused by the gravitational pull of the moon and sun.
The gravitational pull causes a bulge (HW) and two LW on the earth's surface.
The HW on the opposite side is caused by centrifugal force, as earth spins at 1,000 miles per hour.
The moon orbits the earth every 28 days, causing bigger tides and smaller tides, when the sun and moon are in line (transit) or opposition.
BIG TIDES
SPRING TIDES
(transit) occur shortly after new and full moon.Channel harbours, about TWO DAYS after...
Small Tides
NEAP TIDES
(opposition) occur shortly after the 1st and last quarter. Channel harbours, about TWO DAYS after...
7 days between a spring and neap.