chart and publication secrets 3
area of blue water. Trace this solid curved line, called a contour line, and
you’ll fi nd a depth, or sounding, printed in bold type in a break along the
curve. Th e waters outside the curve will have low-water depths greater
than that sounding. Dashed or dotted curves bounding blue water are less
trustworthy and should be given a wide berth. Some charts show diff erent
tints of blue.Flat Beach, High Cliff s, or Soaring Peaks?
In a blow, would you want to anchor off a fl at beach or in the shelter of a hill
or cliff? On the one hand, a steep cliff sometimes blocks an onshore breeze so
eff ectively that you’ll fi nd no wind at all for some distance seaward of it. On
the other hand, when you’re sailing you should be aware that winds sometimes
tumble down steep cliff s like snowballs down a mountain, creating gusty katabatic
winds called williwaws near their bases. Th e wind velocity could double when
funneled between two steep-sided islands or headlands. (In Chapter 11 you
will learn which land features off er the best protection for anchoring.)
Th is chart of Angel Island illustrates several geographic features. A fl at beach lies between
Pt. Stuart and Pt. Knox. Hachures show the location of cliff s. Th e highest mountains peak
at 500 feet above sea level, providing good visual and radar targets from well out at sea.