Adapting a Fish Finder/Eco Sounder Transducer.

J

Jim@sea

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I want to fit a Fish Finder (with depth display) and the only ones which are available have a Transom Hung Transducer and with my yacht having a canoe shaped stern would seem inappropriate.
Although various people have mentioned that they have successfully glued a transom transducer to the inside of the hull,
I thought of doing it another way.
In my hull there are various obsolete transducers probably from when the boat was new 30 years ago, Perhaps If I take one of them out I could thread the cable through the inside of them then glue (GRP Resin & Mat) then the transom transducer to the outside of the hull.
Or is this too much messing about and would you just stick the thing to the inside of the hull.
 
I cut off the extra bits and stuck mine inside. It works perfectly, and has the advantages of having nothing sticking out, outside, and nothing to get growth on.
 
When I fitted my Garmin fishfinder I ordered a suitable transducer from Airmar. I've never had much success with the in-hull sort.
 
I have just used a blob of resin to stick 3 different transom transducers inside the hull and all worked perfectly. Just do not use epoxy as it can bring away some of the hull layup when removing it.
 
As an example of how well they can work inside a solid GRP layup hull, I stuck one down with Blutack to see if it would work, and seven years later I have not even bothered to glue it down with anything else as it works just fine as a backup depth instrument.
 
I currently have a Clipper depth and speed log. If I fitted a fish finder how far apart should it be from the existing transducer?

Cheers
Phil
 
I have 2 transducers fitted inside the hull they are 0.6m apart and do not interefere with each other. but they do work on different frequencies.
 
I have two, and when we are near enough stationary, the fishfinder one is fine, but the digital one sometimes goes crazy, particularly in shallow water. At least with it going crazy, you know it's crazy, so you know to disregard it.
I have the digital one telling me the depth under the keel, and the fishfinder, which is primarily used for anchoring, giving me the actual depth.
 
Stuck mine down with Vasaline as a temporary "see if it works thro the hull test". That was a year ago and its still there and works fine. Mind you it is on a river boat so no rolly polly.
 
No need to go drilling more holes, to test it and get the best location, just put the transducer in plastic bag, add some water to the bag and the area of the hull you would like to install it.

turn it on and move the bagged transducer over the wetted area/s and hve someone report the performance and quality of the display.

Mark the best location/s and install.

Note it is vital that no air is between the transducer and the water outside. This test will show if the area you have selected is free of air bubbles in the construction (or possibly a layer of foam) so take great care not to have any air trapped between the hull and the transducer when fixing it to the hull.

I just used a bit of Sikaflex11FC to stick a small bit of PVC pipe to the hull then slid the transducer in with a twisting action to ensure no air got trapped under it, that was years ago and still works perfectly.

Good luck and fair winds. :)
 
NormanS said:
I cut off the extra bits and stuck mine inside. It works perfectly, and has the advantages of having nothing sticking out, outside, and nothing to get growth on.
Click to expand...

In hindsight having now bought a fishfinder and having read the instructions it actually says that I can glue the transducer to the hull. Pity the various chandlery's dont know this or perhaps they do as who would buy an ordinary echo sounder when for less money you can buy something which gives more information.
Perhaps PBO could do a fishfinder test.
 
On my first boat I fitted a fishfinder which came with a transom transducer. What I did was to epoxy section of 4" drain pipe to the inside of the hull, having cut the end of it to fit tightly to the contours, while remaining in a vertical attitude. I purloined the 4" cork stopper from one of SWMBO's storage jars and fixed the transducer to its underside using a suitably shaped piece of timber. I then pierced the cork horizontally with a piece of 6mm dowel and cut slots in the upper edge of the piece of pipe, in the manner of a bayonet fitting light bulb, to engage the dowel in such a manner as to positively locate it in a forward facing direction, provide a seal and prevent accidental movement. Then all that remained was to add about half a litre of castor oil, (it doesn't go rancid), to cover the transducer. It worked perfectly.
 
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