Transom mounted transducer on yacht

Storyline

Storyline

Well-Known Member
Joined
11 Oct 2004
Messages
2,086
Location
Liverpool - boat Ardfern
Visit site
I fancy getting a plotter for use at our helm (wheel). I have found a Garmin one with what sounds like amazing sonar capabilities that shows the seabed & fish etc. This would give added interest whilst sailing.

It comes with a transom mounted transducer
(Garmin GT20 transducer). I assume this unit is designed for power boats but wonder if anyone here has installed one on their yacht ? Also, any tips on how to attach it. I don't really fancy screwing into our hull so maybe could epoxy a wood pad and screw into that.

Any other tips or comments gratefully received :)
 
Questions I'd have would be;
How vulnerable would the transducer be when coming alongside in a tender?
The waterline on the transom often changes depending whether the yacht is motoring / sailing. Can the unit cope with being at the surface / submerged at differing times?
Is there no-way to mount it in-hull? in a bath of oil in the bilges similar to a echo sounder.
 
When you say yacht I assume you mean a sailboat as opposed to my motorboat. Anyway if it helps I fitted the same transducer to my motor cat a few months ago. The mounting screws are very short and won’t penetrate the hull - I used some Sikaflex as well just to be sure. The entry hole for the cable can be made well above the waterline. It looks a bit ungainly where I mounted it but it’s working fine - deepest I’ve been has been around 250m. Make sure the supplied cable probably 6m is long enough.
 
Yes those Sonars look great. My Lowrance Fishfinder /Plotter had one, was told that it will often work thru-hull if bedded down well. I have tried it, and very ocassionally it does indeed work, but 99% of the time it doesn't !

Oh well, I really only wanted the plotter so it doesnt really matter.
 
I assume it can't be fixed centrally on the transom (rudder in the way? So one tack will lift the transducer out of the water. I use one of those transducers on a pole when I am using my temporary kit for an amateur survey. I was surprised that some surface clutter might cause a problem but it doesn't. But it has a lot of drag and can pick up weed very easily. You could always get a 'standard' transducer as an extra. You could easily rig the transducer on a pole if the pole can be conveniently lashed to the pushpit?
 
Storyline said:
I fancy getting a plotter for use at our helm (wheel). I have found a Garmin one with what sounds like amazing sonar capabilities that shows the seabed & fish etc. This would give added interest whilst sailing.

It comes with a transom mounted transducer
(Garmin GT20 transducer). I assume this unit is designed for power boats but wonder if anyone here has installed one on their yacht ? Also, any tips on how to attach it. I don't really fancy screwing into our hull so maybe could epoxy a wood pad and screw into that.

Any other tips or comments gratefully received :)
Click to expand...

It will probably be in airiated water,will it cope with that & will also be prone to catching floating lines
 
This has been covered many times. I found out about it when I bought a Garmin 128 fishfinder. Must be at least 15 years ago.

After much searching on here and various bits of advice were considered, they boiled down to this. Stick it inside the hull. "Stick" could be done with many different things from epoxy resin to silicon sealant. I first located a bit on the hull where it gave a signal, making acoustic contact with acoustically conductive paste. This could be KY jelly, untrasound gel (if you have a source or wallpaper paste. Guess which I used. The place I tried was forward of the fore end of the keel and just off the centre line on a bit where the hull was not at too steep an angle but away from any thick GRP on the centre line. I then cleaned the area and stuck the transducer down with a big blob of silicon sealant. You make a big blob WITH NO BUBBLES OF AIR IN IT, and "roll" the sensor onto it and press down. Do something to stabilise it while the silicon cures and that is it. Mine worked 100% of the time and gave depth readings down to over 300 feet.
 
Bodach na mara said:
This has been covered many times. I found out about it when I bought a Garmin 128 fishfinder. Must be at least 15 years ago.

After much searching on here and various bits of advice were considered, they boiled down to this. Stick it inside the hull. "Stick" could be done with many different things from epoxy resin to silicon sealant. I first located a bit on the hull where it gave a signal, making acoustic contact with acoustically conductive paste. This could be KY jelly, untrasound gel (if you have a source or wallpaper paste. Guess which I used. The place I tried was forward of the fore end of the keel and just off the centre line on a bit where the hull was not at too steep an angle but away from any thick GRP on the centre line. I then cleaned the area and stuck the transducer down with a big blob of silicon sealant. You make a big blob WITH NO BUBBLES OF AIR IN IT, and "roll" the sensor onto it and press down. Do something to stabilise it while the silicon cures and that is it. Mine worked 100% of the time and gave depth readings down to over 300 feet.
Click to expand...
+1....
between the keels, inside the hull, stuck down with araldite (having proven it works using a small pool of water in the bilge.)
 
Things have moved on chaps. If it's a downscan or sidescan transducer it will most definitely not work acceptably glued in hull. Through-hull is the only realistic option on a yacht, unless you only want to use it when stationary. Bit of a pain when the bundled packages only seem to come with transom mount transducers.
 
MikeCC said:
Things have moved on chaps. If it's a downscan or sidescan transducer it will most definitely not work acceptably glued in hull. Through-hull is the only realistic option on a yacht, unless you only want to use it when stationary. Bit of a pain when the bundled packages only seem to come with transom mount transducers.
Click to expand...

Before I saw MikeCC's post I was going to add my twohalfpence worth regarding mounting it in a bath of castor oil glassed into the hull, but my suggestion now is to have a look at the manufacturer's website to see if they supply an alternative through hull transducer.
 
I had a Garmin colour fishfinder with a transom mount, admittedly it was on a small mobo, i little advice if i may, fasten the transducer onto a flat piece of wood and clamp it to the transom, this will allow you to try different positions and observe how the display behaves, you can them mark where it will be fastened, it is as mentioned only fixed with a couple of short screws and epoxy, they work very well if fixed correctly, and do not need to be below hull level.
 
Storyline said:
Garmin do produce a transducer that can be stuck down in hull but as MikeCC points out the cheap bundles you can get only seem to come with these transom mounted ones.
Click to expand...

Yes, I was suggesting to the OP that if he should buy the cheap bundle, he should then invest in a compatible through-hull transducer to enjoy the full capabilities of his purchase.
 
Storyline said:
Garmin do produce a transducer that can be stuck down in hull but as MikeCC points out the cheap bundles you can get only seem to come with these transom mounted ones.
Click to expand...
To clarify, AFAIK an in-hull downscan or sidescan transducer isn't possible. This is due to the much higher frequencies used not transmitting well through GRP.
 
I have had a b/w since 2000 ish, It came with a "transom mount" transducer that others on here said could be used in hull, so I glued it there and it has never failed me.

Test it first in hull.
I bet it works.
 
I fitted a transom mount Garmin in our Sabre & it worked perfectly, Stuck it in temporarily on a wodge of blutack, when we found a good spot It was stuck in with silicone rubber. Then i managed to a
damage the cable & fitted a Lowrance, that worked perfectly as well. These £100 fishfinders do everything an echo sounder does & more.
 
You must log in or register to reply here.

Share this page

Top