Extra Fish!

[rseas]

I had posted this as a reply to a comment to a fishing report that I posted and thought that it may be of interest or useful to the Washingtonlakes members. The original comment or question was “What type of interference were you experiencing? When I run my big motor, my Humminbird screen fills with fish!." and was made in response to a closing comment I made in my Lake Stevens report from Sunday. “On a positive note, my efforts in rewiring the boat were very successful. I have absolutely zero electrical interference or noise on my Humminbird FF and the electrical system has the appropriate circuit protection.”. Sorry about being long winded and here is the good stuff.

As the result of lessons learned from previous fish finder/transducer installations I am familiar with the “fish while running issue” but in my case the electrical interference was primarily due to ESD from my electric trolling motor. To address the “extra fish”; for my boat/transducer setup I found that the depth and placement of the transducer was critical in reducing the extra fish symbols that appear when I put the boat on plane. I run a Hummingbird QuadraBeam PLUS transducer and knew that placement was critical. So when I did the initial installation I started out using a portable or suction cup transducer mount. My plan was to identify the ideal mounting location for different operational conditions using the suction cup portable mount and then install the hard mount once I established where the ideal mounting location should be. In reality the portable mount works perfectly and has the benefit of being removable when I have to beach the boat so I never installed the permanent mount. On my boat there is a flat area on the transom where the lower edge is parallel to the water surface just inboard of the chine. If I place the transducer in this area so that it is just wetted while running I seem to eliminate most of the excess fish while running. I should probably mention that typically I do not use the fish ID feature and prefer the arches but I am familiar with your concern. I believe that the extra fish are actually surface turbulence interpreted by the fish finder as fish.

Regarding the ESD, I revised the overall power distribution by increasing wire gage and basically separating the fish finder power supply from the trolling motor wire routing. Additionally I made a point to separate the trolling motor wiring from the transducer cable.