Understanding Nav Aids - NorthStar 951X Operator's Manual

Chapter 4 - Using Charts

Understanding nav aids

Buoys
Page 44
You may be able to use the displayed boundary lines to pre-
dict when this change in detail is about to happen.
Occasionally, you may see an hourglass symbol displayed
briefly in the information window on the screen while the
chart is changing or being redrawn.
The nav aids found on the unit's electronic charts are repre-
sentations of a variety of common "aids to navigation" used
throughout U.S. coastal and inland waterways. Most of these
aids to navigation consist of buoys, lights, lighthouses, and
daybeacons, and typically are maintained by the U.S. Coast
Guard. The purpose of nav aids is to warn mariners of hidden
dangers—such as underwater hazards—and to enable them to
safely navigate specific waterways and channels.
The unit's nav-aid data has been manually converted from offi-
cial paper charts to the electronic format on your screen and is,
therefore, not necessarily as accurate as the source charts. An
average of 95 percent accuracy should be expected in the tran-
sition from paper to electronic format. In some areas, only the
most important nav aids may be shown.
In the 951, nav aids are typically illustrated on the CHART
screen as black circles with white letters. The most common
nav aids depicted on the charts are buoys. Those illustrated by
a letter "G" represent green channel-marker buoys; a letter "R"
indicates a red channel-marker buoy, "W" indicates white; and
"Y" is for yellow. Approach buoys are shown as circles with
black on the upper half and white on the lower half. In the
952, green, red, white, and yellow buoys are represented by
those actual colors (except when the 952 display is set for
nighttime viewing, which uses either black or magenta colors).
CAUTION!
951/952 Operator's Manual Rev. B