Garmin FishFinder 340C Owner's Manual page 36

U F 340C > U
SING THE ISHFINDER
in sonar data presentation and is recommended for all
applications. The presentation is based on bottom strength.
It makes the bottom and the fish easier to see and requires
fewer adjustments.
• 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.
• Automatic Scroll Speed Limit—automatically adjusts
the scroll rate (see page 37) with the speed of your vessel
when the Scroll option is set to Auto (if equipped with a
speed sensor or receiving GPS NMEA input). 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.
• Transducer Type—allows you to specify what type of
transducer you are using.
30
M M
SING THE AIN ENU
• Calibrate Water Speed—this appears only if you are using
a speed-capable transducer/sensor. Calibration is required
to ensure that the water speed displayed on your Fishfinder
is accurate. The Fishfinder automatically uses GPS ground
speed (if available using NMEA input) 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. Use the Rocker to highlight Calibrate Water Speed, and
press ENTER.
2. Bring the boat to a cruising speed. Both the top GPS ground
speed and uncalibrated water speed appears at the bottom
of the calibration window. Note your top speed, then stop
the boat, and press ENTER.
3. By default, the top 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.
Fishfinder 340C Owner's Manual