Other Aids - Marks |
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Dayboards
These
diamond shaped marks are used to help the vessel operator determine location on
a nautical map.
When you see a dayboard, and find the corresponding mark on the
chart, you know your precise location.
They may be lettered, and may be lighted
with a white light. Their color reflects that of nearby lateral marks.
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Safe Water Marks
These marks are used to mark fairways, mid-channels, and offshore approach
points. They have unobstructed
water on all sides. These marks may be lettered,
and may be lighted with a white light. They may also have a
red top mark.

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Isolated Danger Marks
These indicate a danger which may be passed on all sides. They are erected
on, or moored on or near danger.
They should not be approached closely without
special caution. They may be lighted, and they may be lettered.

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Special Marks
Special marks have no lateral significance (meaning they don't tell you which side of the channel or river you may be on). These marks are used to
mark a special feature or area. These include area limits for anchorages,
fishing grounds, or dredging/spoil areas. These buoys may be lighted, and
if they are it will be a fixed or flashing yellow light. Shape is
optional, but usually follows the shape of the navigation buoys that it is
positioned near.
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