In-Hull transducers are attached to the inside of the hull of the boat and conduct sound directly through the hull. Puck style transducers are usually used for this application, but any type will work. When properly mounted, an In-Hull transducer will give a very clean reading at any boat speed. The advantage of In-Hull mounting, besides clearer high speed readings, is that there is nothing mounted to the boat externally to get damaged or snagged on weeds. This can be a great benefit on bass boats and even canoes.
The disadvantage is that it’s more difficult to mount and to remove if something goes wrong. Here are some tips to help insure a good mount so that, hopefully, you can get a good installation the first time.
1.Find the spot where you will mount the transducer. The best place is in the center of the hull near the transom. Boats differ in hull design and quality. Once you find an accessible spot you should test it before you glue down the transducer.
2. To test the spot you need to make sure it is clean of dirt, oil, gas, and general bilge slime. Once the spot is clean it’s time to head for the water. After the boat has been launched, put some water in the bilge, just enough to cover the area where the transducer will be mounted
3. Now the tricky part, hold, or have someone or something hold, the transducer in place as you drive the boat. A ziplock bag of sand can be handy for this. You should have a good reading as the boat moves slow, if not, move the transducer around until you do. Get the boat up on plane and see how your reading changes. If the reading becomes scrambled to the point where you cannot determine what the bottom is you are shooting through “white water” and you’ll need to find a new spot. If the reading looks good you’ve got your spot.
Once you know where you want to attach the transducer, and you’ve got the spot dried out, you can begin the gluing process. A good two part epoxy, such as the Vexilar A.C.E. adhesive, is the best glue as far as being a good conductor of sound.
For mounting in aluminum hull boats you should use a transducer specially designed for aluminum in-hull mounting. Normal transducers will have signal losses of up to 70%. Many sonar systems will fail to show a bottom with losses like this.
The key to a good glue job is making sure that the surface is clean and that there are no air bubbles in the glue. Once you’ve got the transducer in the glue, move it around and force all the air out before you set it into place. Do not turn on the depth finder before the glue is completely dry.
Follow these steps and you’re sure to get a good in-hull transducer installation.