chart and publication secrets 11
within the boundary lines. More oft en, however, you’ll see the warning See Note,
which is an indication to look at one of the descriptive blocks of text on your chart.
Be extra cautious when sailing at night near fi sh-trap areas; they’re unlighted!
Spoils, dumping grounds, and fi sh havens. Inland and coastal charts oft en
show circular or square areas of blue water with no soundings. Ever wonder
where old cars, boats, ships, dredge material, and excess garbage end up? Th ese
spoil areas or dumping grounds are subject to changing depths, so surveyors
rarely bother trying to keep them updated with soundings. Sometimes you’ll
fi nd the words Least depth__ft printed over the middle of such an area, but
don’t trust it. Stay clear and go around—not aground.
Sparse Soundings
It’s always a good idea to avoid any charted area showing sparse, widely spaced,
or missing soundings. You never know what underwater monsters lurk there,
just waiting to ruin your perfect underway day.
Solve the Mystery of Aid-to-Navigation Symbols
Charted aids to navigation (ATONs) give the mariner a clear picture of their
basic characteristics. All buoys are anchored to the bottom and swing in a small
radius.
BUOYS
Two shapes represent a buoy body on U.S. charts: the fi rst is a diamond; the second,
much-less-common shape is a pie-pan viewed in cross section. Diamonds make up
the majority of fl oating-aid chart symbols, while pie-pan shapes represent mooring
buoys. On one end of the buoy symbol is a small open circle known as the swing
circle. Th e buoy’s actual position at any time lies within this swing circle.
Diamond-shaped buoy bodies may be white, green, red, yellow, red and
white, red and green, or red and black. Th e diamond may be segmented hori-
zontally or vertically with a line or color change. Some diamond symbols show
one or more tiny circles on the end opposite the swing circle. Th ese represent a
Chart symbols for buoys, from left to right: unlighted buoy, unlighted mooring buoy, buoy
with vertical stripes, buoy with horizontal stripes, and two buoys with topmarks.