Topic: Finding Rocks in the Water with 997

[sorabrab]

DEAR SIR,

I HAVE 997CSI COMBO,
IHAVE PROBLEM ABOUT FIND A ROCKS UNDER THE WATER.

WHİCH COLORS ABOUT ROCKS OR HAVE CAN I USE THE SONAR. FIND A ROCKS UNDER THE WATER.
THANKS FOR HELPING.

[Humminbird_Greg]

It will depend on what the rest of the bottom is composed of (either a soft or hard bottom) and how it is shaped (flat, smooth or irregular) whether you will be able to see rocks at all.  How the unit is adjusted will also have an effect on this.

In the 2D sonar I would try and set the Sensitivity menu such that little to no Red (if you are using the Original color pallet) shows when over a soft bottom.  That way when you go over a rock it should appear as red since the rock will reflect back more sonar energy.  You can also watch the second sonar echo return for an indication that the bottom is harder.  If the Sensitivity is set correctly you will see no or a slight second return echo until you go over something harder in which case the second return will show up or show with a stronger sonar signal.  See image below.

In Si sonar it’s mostly the shape that will give away the rocks but you will also see a stronger sonar return as well.  Sorry but I don’t have any Si images of rocks…