Loosing/Unable to hold bottom.

I was out on Lake Michigan this weekend and I was having trouble with my birds. I have a 997 at the helm and a 917 on the bow. Once we got out past 180′-200′ of water both units had difficulty holding the bottom and providing an appropriate depth.

After trying to adjust everything the only thing that seemed to work was to set the area of interest from 0′ – 140′ of water. Then the unit would show the predetermined depths and tell you the appropriate depth (ie. 323′ or whatever).

I have a glassed in transducer as well as the Side Imaging transducer at the stern and the universal transducer on the Terrova at the bow.

Any ideas on what’s going on? Was my ping speed set to low for those depths? Did the pounding (5′-6′) waves give me problems? I know even with my chart speed set at 9 it was moving really slow.

Last summer on Lake Nipigon I was running a high speed external transducer and I had no issues reading 300’+ at 40 MPH in calm water.

Its the angle of your glassed in transducer. When they installed that, you have a Y cable that splits the transducer functions from teh 2D to the glassed in puck. The imaging is done on the stern mounted ducer. In the waves you described, your boat wasn’t maintaining the forward pitch. Also, you would have had a lot of cavitation happening beneath your boat and the signal loss would be great. A few weeks ago up at Door County, I ran out to 200′ off of Washington Island. It was like glass when I went out, and had perfect bottom track. Coming back in in 3 footers, had the same thing with the unit showing 300’+ Depending where the large ducer is mounted off of the stern and how it tracks in rough water may determine if you want to remove the Y cable and discontinue the use of the puck. Didn’t work for me because my SI ducer is raised too high and is out of the water at full throttle.

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Its the angle of your glassed in transducer. When they installed that, you have a Y cable that splits the transducer functions from teh 2D to the glassed in puck. The imaging is done on the stern mounted ducer. In the waves you described, your boat wasn’t maintaining the forward pitch. Also, you would have had a lot of cavitation happening beneath your boat and the signal loss would be great. A few weeks ago up at Door County, I ran out to 200′ off of Washington Island. It was like glass when I went out, and had perfect bottom track. Coming back in in 3 footers, had the same thing with the unit showing 300’+ Depending where the large ducer is mounted off of the stern and how it tracks in rough water may determine if you want to remove the Y cable and discontinue the use of the puck. Didn’t work for me because my SI ducer is raised too high and is out of the water at full throttle.

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My SI transducer is to high as well. Thanks Randy.