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display. Soft bottoms such as
mud or sand appear as a thicker
line having a transition from dark
to light grays. Bottoms made up
of many rocks have a broken,
random appearance.
Bottoms having a large degree
of slope also present a unique
picture. These generally have a
thicker black band representing
the bottom directly under the
boat. Equal areas of gray above and below the black band represent sonar
returns from around the boat.
A second sonar return may be visible if the appropriate depth range is
selected. This appears as a depth contour below the main bottom contour,
at twice the depth. The second return occurs when the sonar signal bounces
between the bottom and surface of the water and back again. Some anglers
use the appearance of the second return to determine bottom hardness.
With a lower gain setting the second return will be more faint, except in
areas with hard bottom. The 160 has a unique depth range feature which
permits the second return to be visible in any depth range. See Modes of
Operation for details.
The 160 displays structure such as submerged grass, brush, trees and wrecks
on the bottom. Structure can be distinguished by comparing the area just
above and below the main bottom return. Usually structure shows as areas
of dark to light gray on top of a dark bottom contour. The appearance of
structure is greatly affected by boat speed and direction; to repeat the same
image it is often necessary to travel the same speed and direction over the
location where the structure was originally located.
The 160 is also capable of showing layers of water having different
temperatures. These temperature differences, called thermoclines, appear at
different depths, depending on current conditions. A thermocline typically
appears as a continuous band of many gray levels moving across the display
at the same depth. Thermoclines always appear above the bottom.
Schools of bait fish as well as individual fish are clearly visible on the 160
display. Bait fish appear as "clouds" having different shapes and sizes
USING THE 160
CONTROL FUNCTIONS
Thermocline
Slope
Second
Return
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