[CA] [CA11] '76 Mako Transducer Location - Dragonfly 7

[mugwump4]

Need some help with proper transducer location. I mounted it initially at the bottom of the bilge, with it shooting through the hull. I had no issue with reading bottom at speed, but did lose some of the advertised bottom clarity that was advertised.

I have since mounted the transducer on the transom and now lose the depth at anything just over fast trolling speeds. As soon as I slow down, the reading comes back. I have attached some pictures of my transom and mounting. The boat is a '76 Mako 23' center console with a full flotation bracket. Any guidance would be greatly appreciated.

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum mugwump4,

Please click here to view a FAQ addressing this subject. In this case, it appears that the transducer has been installed on the incorrect side of the transom. For single outboard / single I/O applications, the transducer should be installed on the starboard side of the transom. As noted therein, lowering the aft end of the transducer a notch or two can also improve performance at speeds nearing plane and while on plane.

[mugwump4]

Understood all the above. I can try adjusting the end of the transducer, but why does the side of the vessel matter? It read fine in a thru-hull location on the port side. The transducer is at least 3 feet from the prop?

[Chuck - Raymarine - Moderator]

mugwump4,

As indicated within the installation guides for transom mounted fishfinder transducers, you will find that it calls for transducers installed on single outboard and I/O drives to be installed on the starboard side of the transom. This is because clockwise rotating props will cause aerated water on the port side of the transom which can adversely affect transducer performance. This pressure will increase with increase in RPM. Fishfinder transducers which are installed within or through the hull are typically installed well forward of the transom where they are well away from this aeration source. That said, you may want to consider dropping the aft end of the transducer and re-testing prior to moving the transducer to the starboard side of the transom.