Sonar and Rocks

Fish like rocks and one of my favorite fish to catch likes boulders (smallmouth bass). After we figure out the fish are relating to boulders we need to find more spots with rocks and boulders so we have more choices. Maps help because if the best rocks are at 15 feet we can find 15 foot spots on the maps. You must have a high definition map created by Navionics or LakeMaster to be able to use maps. LakeMaster has maps in the Upper Midwest and I prefer their maps because they have the best detail. I used their Winnie map at the last tournament to find rock spots.

I after you have some places to check out you need to find the rocks with the sonar. Rocks show up as hard bottom with bumps. The bump size depends on the size of the rocks. I use the side scan to find boulders off the side and the regular sonar and DownScan to find rocks and determine the size. The DownScan shows big rocks as spikes and the fish show up better with DownScan because the cone size is narrower and gives better target separation.

This example shows large boulders and a transition to the side of the boat. Lowrance allows me to mark a waypoint on the boulders so I can drive right to them.

I created a waypoint on the boulders and drove over the boulders to get this screenshot.

This screenshot uses the DownScan to show the boulders as spikes and the fish separated from the bottom better than the traditional sonar. The bumps on the traditional sonar are the small boulders and the fish has red instead of yellow. Yellow is the strongest echo return so the boulders give a stronger echo than the fish. The problem is the traditional sonar doesn’t separate the fish from the boulders as well as the DownScan. Notice the cursor above the fish in both views so that I know it is the same fish. The DownScan chart speed is faster than the traditional sonar so it appears less compressed.

Go Fishing, The Clock is Ticking
Doc