There are several advantages to running a transducer for your dash mounted electronics and LCD’S in the sump area of the boat. These include the added protection for the transducer and decreased drag on the hull, not to mention the fact that you don’t have to drill holes in the boat transom.
Mounting the transducer is fairly simple, assuming your sump area is open enough to allow you to reach the area at its lowest point, just forward of the drain plug hole. The keel below this area is generally solid fiberglass and resin cloth, which gives the best area for good sound wave transmission. If you have any doubt about the mounting area, go to a launch area, place the transducer in the area intended for mounting, add water to a level to cover the transducer(if this is possible in your boat’s configuration) and idle around, observing the electronic’s display. If you get a good clear signal during this process, you can be confident that your selection for a mounting area is a good one.
Once you’ve selected the installation area, clean it thoroughly with Simple Green Cleaner, to remove dirt and grease, then clean the area again with a cloth lightly soaked in acetone. Do this very lightly, because Acetone will dissolve resin if you pour it on. Next, sand the installation area lightly, from at least two directions, with 600 grit sandpaper, and wipe the area out. Next, sand the face of the transducer that will point down with the same 600 grit. This insures a good bond with the epoxy. A Puck type transducer is easier to install, but a skimmer type will also work here.
Once you’ve finished the sanding, make a ring of plumber’s putty or kid’s Play Dough to form a dam for the epoxy. Press the putty ring onto the area of the sump where you want the transducer to be, and then mix an entire tube of Devcon Plastic Welder epoxy in a plastic butter tub or other similar discardable dish, and then transfer the entire mixture to the dam ring. Level with a plastic knife or tongue depressor and press the transducer in place, twisting slowly to displace any air bubbles. I then put a 4 pound square lead scuba weight on top of the transducer to hold it in place for 24 hours to insure a good seal and hardening. These scuba weights work very well because they provide a flat surface that lays well on top of the transducer, and because they offer a lot of weight in a small object. Check to insure that the epoxy has hardened, and then remove the putty ring, and your done.
Routing of the transducer cable depends upon the individual boat involved in the installation, but a “fish-tape” or “snake”, a tool used for pulling wires through interior walls is a very handy and sometimes critical tool in the installation process. Run the wire tape down the starboard side of the boat, extending it back to the corner of the transom where it should be reachable from the sump area. Attach the plug end of the transducer cable to the fish-tape by wrapping it completely with black electrician’s tape. The plug should be wrapped completely so that it will not hang or become dislodged as it is being pulled back through the cable space under the gunnel of the boat. If the fit is tight, spraying the taped area with silicone spray(Blakemore Reel/Line Magic ) will make it much easier to pull. Maintain a steady pressure as you retrieve the tape, twisting or pushing and pulling if a tight spot is encountered. Once the plug end is positioned properly under the console, coil the excess cable and secure it under the console with a tie-wrap.
Some installation tips: 1. Some boats may require that bilge pump or aerator hoses be disconnected in order to have access to the sump area. Be sure to label, or draw a diagram of these hoses so that they can be reconnected to the right pump. Connecting the livewell pump to a bilge hose could result in some very dead fish at weigh-in
2. Do not use a quick set epoxy. They can set up with numerous air bubbles between the transducer face and the hull. This kills signal transmission. Devcon Plastic Welder is my choice, but most slow cure epoxy compounds will also work. I have not used it personally, but I’ve talked to several anglers who have used Marine-Tex epoxy with good results.
3. It is better to route your transducer cable to the dash area BEFORE you epoxy in the transducer, just in case you run into a routing problem and need to move the unit.