Junior88,
Thanks for your screen shot. You look to have two issues, one is electrical and the other is water flow. In the case of the electrical, you need to find out how the interference is getting into the sounder, is it through the power or transducer cable. First put the boat in gear so the noise appears. Then disconnect the transducer from the sounder and turn the gain up to 10 to see to the noise is still there. If the noise is still present you may be able to add an inline noise filter on the power leads to suppress it. If the noise goes away you are dealing with a radiated noise being picked up by the transducer, this type of noise is much harder to deal with. If you have another transducer available I would try hanging it over the side in a different location to see if you see any difference. If you do, maybe rerouting the transducer cable may help. Also have you tried grounding the case of the sounder? The other issue a see are the gaps in the bottom which is an indication of turbulence going over the face of the transducer.
Snips
