my thru hull depth transducer that is mounted inside the hull and sits in a small oil cup that is glued to the inside hull is always leaking and have to fill it often. i know i should just reseal it but can i just silicone the transducer to the inside of the hull? i would think it should work if i dont get any air bubbles and use just a thin layer.
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I first sanded the paint off and cleaned the spot with alcohol. I used 3M5200 and it has never leaked. Works just fine. Placement of the hockypuck is the most important part. If leaking is your only problem and the "hockypuck" works OK for you, I'd test your approach with plumbers wax first. If you can find a flat spot with no bubbles under the hull it should work. Some people never glue it down. I tried the wax for a month and it worked just fine and was tempted to just leave it there but the angle was not just right so I followed the instructions and it works just fine. Different strokes...I once helped a friend clean the paddle in his transducer - what a mess. I'll always avoid drilling holes in the bottom of my boat if I can.
Above Hull Transducer
The "puck" type transducer will work but with mixed results on most hulls. I assume that you are using glycerin in the cup. Sonar signals must not have any air (including foam or bubbles) in their path. This includes voids in the hull layup. Once that you have a location for the puck that provides the performance you expect, you can epoxy the puck to the hull. You still need to make sure that no air bubbles are below the transducer. Be aware that this is a permanent installation and will likely never give you the performance and accuracy of a true thru-hull transducer. If it were me, I would try to seal the leak with silicone or adhesive compound for now, and plan on installing a thru-hull transducer when you next have your boat out of the water. Pucks are notorious for sporadic unreliable operation. Good luck! Jon s/v B321 Parrot Tales Kemah, TX
The "puck" type transducer will work but with mixed results on most hulls. I assume that you are using glycerin in the cup. Sonar signals must not have any air (including foam or bubbles) in their path. This includes voids in the hull layup. Once that you have a location for the puck that provides the performance you expect, you can epoxy the puck to the hull. You still need to make sure that no air bubbles are below the transducer. Be aware that this is a permanent installation and will likely never give you the performance and accuracy of a true thru-hull transducer. If it were me, I would try to seal the leak with silicone or adhesive compound for now, and plan on installing a thru-hull transducer when you next have your boat out of the water. Pucks are notorious for sporadic unreliable operation. Good luck! Jon s/v B321 Parrot Tales Kemah, TX
Puck Location
Put the puck in a ziploc bag filled with water and move it around the boat to find where it works the best,clean that spot,apply a BIG glob of silicone and push the puck into it so there are no voids. Test and the job is done. Should you ever want to change the transducer no big deal to remove. My installation works very well.
Put the puck in a ziploc bag filled with water and move it around the boat to find where it works the best,clean that spot,apply a BIG glob of silicone and push the puck into it so there are no voids. Test and the job is done. Should you ever want to change the transducer no big deal to remove. My installation works very well.
Silicone sometimes has air bubbles -
that's why the manufacturers of transducers that shoot though the hull recommend using 30 minute epoxy. Do the puck in a water filled poly bag set against the hull, and verify the location for accuracy. Then mold a dam of model clay so the epoxy will be flat and not flow. Mix your epoxy, set the puck in it, let dry, and you will have an installation that will work as long as you own your boat. Make sure your location is only fibreglass - the unit won't shoot through wood or foam.
that's why the manufacturers of transducers that shoot though the hull recommend using 30 minute epoxy. Do the puck in a water filled poly bag set against the hull, and verify the location for accuracy. Then mold a dam of model clay so the epoxy will be flat and not flow. Mix your epoxy, set the puck in it, let dry, and you will have an installation that will work as long as you own your boat. Make sure your location is only fibreglass - the unit won't shoot through wood or foam.
Transducer wedges
3 years ago when we hauled out our boat I replaced the inside the hull depth transducer with a thru-hull type. Since our home port is Pearl Harbor, HI I fashioned wedges to square up the transducer one inside and one outside of the hull out of Koa wood and installed them with 5200. Last year I noticed that the Koa seems to be weeping a little. We are going to do a haul out on the 12 of November this year and would like to ask these questions. A: do I need these wedges to square up/level the transducer to get an accurate reading and B: should I use a different type of wood/material for my wedges or is Koa wood ok? The transducer is located out from the keel about 18". The wedges at thier thickest point are maybe 1 1/4" thick.
3 years ago when we hauled out our boat I replaced the inside the hull depth transducer with a thru-hull type. Since our home port is Pearl Harbor, HI I fashioned wedges to square up the transducer one inside and one outside of the hull out of Koa wood and installed them with 5200. Last year I noticed that the Koa seems to be weeping a little. We are going to do a haul out on the 12 of November this year and would like to ask these questions. A: do I need these wedges to square up/level the transducer to get an accurate reading and B: should I use a different type of wood/material for my wedges or is Koa wood ok? The transducer is located out from the keel about 18". The wedges at thier thickest point are maybe 1 1/4" thick.
Wedges
DJW, I had the same situation on my boat. The transducer went through the hull and pointed at about 35 degrees to the sea bottom. Needless to say the accuracy of the instrument was compromised. On a haul out last year the yard made wedges out of starboard material. They shaped it like a bullet and mounted the transducer inside. The depth instrument read accurately and there is no appreciable amount of drag due to the wedge. I would think that you or your yard there in Hawaii could fashion a wedge out of startboard pretty easily. Starboard would be better than any wood below the waterline. Good luck.
DJW, I had the same situation on my boat. The transducer went through the hull and pointed at about 35 degrees to the sea bottom. Needless to say the accuracy of the instrument was compromised. On a haul out last year the yard made wedges out of starboard material. They shaped it like a bullet and mounted the transducer inside. The depth instrument read accurately and there is no appreciable amount of drag due to the wedge. I would think that you or your yard there in Hawaii could fashion a wedge out of startboard pretty easily. Starboard would be better than any wood below the waterline. Good luck.
Fiberglass
Carl, I have a similar installation as yours. When I installed my transducer I made the cup out of 3" PVC pipe, but I fiberglassed it to the hull. It has never leaked. By the way the recommended oil is mineral oil, or baby oil, found in any local pharmacy. As others have mentioned, the silicone and epoxy method can work but you really never know if you have air bubles or not. Since the cup is already there, I would invest a little labor to re-seal it with any of the methods mentioned. By the way the performance of the depthfinder has been flawless at any angle of heel.
Carl, I have a similar installation as yours. When I installed my transducer I made the cup out of 3" PVC pipe, but I fiberglassed it to the hull. It has never leaked. By the way the recommended oil is mineral oil, or baby oil, found in any local pharmacy. As others have mentioned, the silicone and epoxy method can work but you really never know if you have air bubles or not. Since the cup is already there, I would invest a little labor to re-seal it with any of the methods mentioned. By the way the performance of the depthfinder has been flawless at any angle of heel.
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