Garmin GPSMAP 3005C - Manual (Page 87)

GPSMAP 3005C Owner’s Manual 
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• Automatic Scroll Speed limit—automatically adjusts the Scroll rate with
the speed of your vessel. Entering your maximum cruising speed produces
a 100% scroll rate when you reach that speed. One half of that speed
produces a 50% scroll rate, and so on. The default is 30.0 kt.
• Keel Offset—allows you to offset the surface reading for the depth of a
keel. This makes it possible to measure depth from the bottom of your keel
instead of from a transducer’s location near the water line. Enter a positive
number to offset for a keel. You can also enter a negative number to
compensate for a large vessel that may draw several feet of water, requiring
the transducer to be submerged if you want to measure from the water line.
The Keel Offset is reflected in the depth reading.
Transducer at surface.
Enter (+) a postve
number to show depth
from bottom of keel.
Transducer at bottom of keel.
Enter (-) a negatve number to
show depth from surface.
• Transducer Type—allows you to specify what type of transducer you are
using, either Dual Beam or Dual Frequency.
• Custom Range—allows you to specify a custom viewing range or scale.
When On, this range appears as Custom in the Range setting. The left
value is the top of the scale and the right value is the bottom of the scale.
• Calibrate Water Speed—this is available only if you are using a speed-
capable transducer/sensor. Calibration is required to ensure that the Water
Speed shown on your unit is accurate. The unit automatically uses the GPS
ground speed, if it is available, for comparison on the calibration. If a GPS
ground speed is not available, use either your boat’s speedometer reading
(not always accurate) or a stopwatch to determine your speed over a certain
distance (distance / time = speed). It is recommended that the calibration
take place in water having little or no current.
To calibrate the water speed:
1. On the Sonar tab, press the Cal Water Spd soft key.
2. Bring the boat to a cruising speed. Both the top ground and uncalibrated
water speeds are shown at the bottom of the calibration window. Note your
top speed, stop the boat, and press ENTER.
3. By default, the top ground speed automatically appears in the “What
was your top water speed?” field. If a ground speed is not available,
the top uncalibrated water speed is used instead. If the new speed is
correct, highlight OK, and press ENTER. If you want to manually enter
a calibration, press ENTER on the speed field, enter a new speed, and
press ENTER.
Graph Sub Tab
Use the Graph sub tab to select the color scheme, fish symbols, and scale.
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