Mounting the transducer for a side scanning fishfinder, like Structure Scan from Lowrance and Side Imaging from Hummnbird, seems to be a constant topic of confusion. I get questions on it regularly, including this one from a reader in Florida, which came through today:

I’m interested in putting a lowrance sidescan on my 27 Ameracat but in the past, I’ve  had to mount two transducers, on on the outer part of each sponson to avoid blocking the sidescan.   It doesn’t sound like you had that problem with the lowrance.   Wondering if you would share the mounting location of the LSS1 lowrance sidescan transducer.

No problem: I mounted the ducer on the starboard side of the starboard hull, just outboard of the engine. (I already have a ducer mounted on the port side, for the HDS down-looker.) It’s a tight fit, and when the engine’s trimmed all the way in and turned to port, there’s just a fraction of an inch of clearance. But it doesn’t seem to effect performance one iota.

These transducers shoot an incredibly thin (one-degree, 455- or 800-Khz, in the case of the Lowrance) beam, so it can thread the needle right in-between the outdrive and the transom of the boat. Here are a couple of shots of how it looks, on my 22′ Glacier Bay:

side imaging transducer mount lowrance structurescan

The side imager is mounted to starboard of the outdrive, with the down looker to port.

 As you can see, the very end of the ‘ducer does extend a tiny bit beyond the edge of the drive, but that’s not enough to interfere with the Structure Scan. (Note that the curved tail end of the transducer, not the flat bottom section, protrudes past the drive. As long as the flat bottom part isn’t blocked you’re fine.) Also note that rigging the transducers this way keeps them about a foot apart, which is ideal for down-imaging and gets you the optimum performance and detail on the downward view (for which the unit combines returns from the sonar and the side scanner.) Here’s another shot, from directly behind the outdrive, which shows the spacing from a different angle:

transducer mount for side scanner

This arrangement keeps the side scanning and down looking transducers within a foot of each other, which is ideal for down scanning as well as side scanning.

As you can see it is a tight fit, but considering the fact that this was done on a Glacier Bay, there shouldn’t be many (any?) cases in which the transom will be more cramped then this one is. Hopefully, this’ll help everyone get their transducer location just right – because once this system is up and running, it’s super-sweet!