Chart Speed; Bottom Lock (Sonar Zoom View Only); Bottom Range (Sonar Zoom View Only When Bottom Lock Is On) - Humminbird 598ci Operation Manual

Chart Speed determines the speed at which the sonar information moves across
the display, and consequently, the amount of detail shown.
A faster speed shows more information and is preferred by most anglers;
however, the sonar information moves across the display quickly. A slower speed
keeps the information on the display longer, but the bottom and fish details
become compressed and may be difficult to interpret. Regardless of the Chart
Speed setting, the RTS Window™ will update at the maximum rate possible for
the depth conditions.
Bottom Lock changes the mode of the zoomed view in the Sonar Zoom View.
Bottom Lock continuously graphs the bottom at a constant point on the display
regardless of changes in depth. This "flattens" out the bottom contour but is
effective at showing fish on or near the bottom.
Bottom Range allows you to control how much of the water column, measured
up from the bottom, is shown in the Sonar Zoom View. Choose a small value to
see low-lying bottom structure or details of the bottom return. Choose a larger
value to see large structure in deeper water.
NOTE: It is possible to set the Bottom Range to be greater than the depth. In this
case, you may see surface clutter in a wavy band that mirrors changes in the
depth.

Chart Speed

Settings: 1 - 10, where 1 = Slow, 10 = Fast; Default = 5
Bottom Lock
(Sonar Zoom View only)
Settings: Off, On; Default = Off
Bottom Range
(Sonar Zoom View only when Bottom Lock is On)
Settings: 10 to 60 feet, 2 to 10 fathoms, or 3 to 20 meters
(International Models only); Default = 15 ft
101 Sonar X-Press™ Menu