Cardinal Marks flash a white light at night to tell you where there is safe and Navigable water – they keep you away from a danger ie reef, rock, submerged object.
A great way to remember the flash sequence and what cardinal it is, is to think of a clock face.
East is 3 flashes, stay to the east of this marker – safe water lies to the east
. . . . . . . . .
West is 9 flashes, stay to the west of this marker – safe water lies to the west
. . . . . . . . . . . . . . . . . .
South is 6 flashes + 1 long flash, stay to the south of this marker – safe water lies to the south . . . . . . _ . . . . . . _
North is continuous flashing; stay to the north of this marker – safe water lies to the north . . . . . . . . . . . . . . . . . . . .
