Lowrance LMS-320, Operation Instructions Manual

Page: 84 / 204

76
NOTE:
Reset Options does not erase any waypoints, routes, plot trails, or
sonar logs.
Reset Water Distance
The sonar chart's Digital Data display option includes a window that
shows distance traveled, called Water Distance ("W Distance"). This
information is calculated from an optional water speed sensor, not the
GPS. The Water Distance window can be reset to zero using the Reset
Water Distance command.
Press
MENU
|
MENU
|
↓
to
S
ONAR
S
ETUP
|
ENT
|
↓
to
R
ESET
W
ATER
D
IS-
TANCE
|
ENT
. The menus are cleared and the water distance is reset to 0.00.
Set Keel Offset
This unit measures water depth from the face of the transducer. Since
the transducer is installed below the water surface, the distance dis-
played by the digital depth, chart depth scale, chart cursor or fish sym-
bols is
not the exact water depth. If the transducer is 1 foot below the
surface, and the screen shows the water depth as 30 feet, then the ac-
tual depth is 31 feet.
On sailboats or other large vessels with deep drafts, the distance be-
tween the transducer installation and the keel or lower engine unit can
be several feet. In those cases, an inexact depth reading could result in
grounding or striking underwater structure. The Keel Offset feature
eliminates the need for the navigator to mentally calculate how much
water is under his keel.
Keel Offset lets you calibrate the digital depth: chart depth scale, chart
cursor depth and fish symbol depth displayed on the screen. To calibrate
the depth indicators, first measure the distance from the face of the
transducer to the lowest part of the boat. In this example, we will use 3.5
feet. This will entered as a
negative 3.5 feet, which makes the depth indi-
cators perform as if the transducer's lower in the water than it really is.
1. Press
MENU
|
MENU
|
↓
to
S
ET
K
EEL
O
FFSET
|
ENT
.
2. The Keel Offset dialog box appears. Press
↓
to change the plus (+)
sign to a minus (–) sign.
3. Press
→
to the first number, then press
↑
to change the number to 3
4. Press
→
to the second number, then press
↑
to change the number to
5, then press
EXIT
. The depth indicators now accurately show the depth
of water beneath the keel.