What does a small magenta circle with a dot in the center and numbered (0-11 on what I saw) arrows of varying lengths and unevenly spaced pointing outward from the circle mean? Bottom of page 41 here. http://www.nauticalcharts.noaa.gov/mcd/chart1/ChartNo1.pdf
It says its a current diagram but how do you read it?
Basically, if there are two arrows, it indicates a reversing current (due to tidal action); if there are a bunch of arrows, it indicates a rotary current.