Depth Gauge installation  Problem Posted by Captain Mike Solution Posted by Riley Smith  Solution Posted by Tom Ray  Solution Posted by Bob, Wandering Fox  Solution Posted by Dennis, SunCat  Solution Posted by Captain Mike, Horizon Cat  I have a Compac Horizon Cat. I am attempting to install a Hawkeye Depth Gauge with an in hull transducer. I am having  trouble getting the in hull transducer to work. I cannot get any readings. It works when hung over the side. Does anyone  have any experience with in hull transducers or any suggestions as to how to make it work or what is the best location in  the hull? Like I said, it will read the depth when hung over the side but not when placed inside on the hull. Any thoughts  will be appreciated. I'm not sure how much you know about this, so here goes, and if you already know any of this just ignore it. The  transducer must be bedded to shoot through the hull. The usual way is to mount it in a bed of epoxy. You must make  SURE there are no air bubbles in the epoxy. In order for you to make sure nothing ELSE in the hull is interfering with the  installation, my suggestion is to either use a plastic baggie full of water and place the transduce on it and try it first, or a  bed of peanut butter. You can move it around and make sure it works this way before you epoxy. Once you make sure the  unit will work where you want it, break out the epoxy. If I am not mistaken some of the marine stores sell an epoxy just  for this purpose. The transducer will NOT work just placing it on the hull by hand. The microscopic air gap will prevent it  from working. Also if there is cored material in your hull where you want to mount it, it won't work. Do a little tinkering  and see if it works.  I wouldn't use epoxy. You can just squish them down into a pile of caulk until the transducer almost, but not quite,  touches the hull. Some people build a little tub and mount them soaking in oil, but that's asking for a mess. Caulk is not as good as epoxy at transmitting sound, so your depth finder will be less sensitive and won't shoot as deep,  but for most purposes it works fine. Don't tell Rachel, but I have even used silicon. Silly Putty the kid toy; I used that on my Seaward Fox. Still works after nearly a year and is holding. Read about using it  on one of these forums. As stated you need to be sure there are no air bubbles. Think of a sonogram where they need to put  a jelly like substance on the skin to shoot through. You can move it around at first to assure you have the best spot. I cut a section of PVC about 3" long and using a mixture of epoxy thickened so that it will form a fillet, glued it to the  inside of the hull (kneadable epoxy will work also). I used PVC with a diameter slightly larger than the transducer. As was  recommended by the manufactured, I put Vaseline petroleum jelly in the bottom and pressed the transducer into the jelly.  It has worked flawlessly for over 6 months and is removable if necessary. I initially used water in the PVC which worked  also but would spill evaporate or spill out during heeling and had to be refilled. I located the transducer inside the port  cockpit locker approximately 6 to 8 inches forward and outboard of the cockpit drain opening. I forgot to mention that I  also used a wire brush on a drill motor to remove all paint in the area.  The Sailboat Company (a Compac Dealer in the Carolinas) recommends the following: The Horizon Cat hull is solid  fiberglass. We have installed transducers in the hull under the floor in the forward cabin. The rug on the floor covers a  removable panel for installation purposes. Ease the edge of the rug up for access. A transducer works well in that position. 104