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Re-installing a transducer... oh, and what IS this thing on my boat?

2K views 10 replies 6 participants last post by  bones92 
#1 ·
So, the transducer on my Laguna Windrose 22 came loose, so I'll be re-attaching it to the hull. Note that it was epoxied, but it seems it came loose.

My question is: can I just clean both surface really well, put a thin layer of silicone gel (i.e. about 1/4" thick), and stick it back on? I know there can be no bubbles in the silicone, so I'd be careful about that.

I thought about chipping off all the old epoxy from the transducer, but I'm concerned I might crack the housing.


Also, what is that odd thing in front of where the transducer was attached? I can't tell if there is something encased in the fiberglass. Could it be an attachment point for when the hull was made, so the hull could be lifted into place for assembly?

Thanks!
 

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#2 ·
SAND both surfaces with 60 grit sandpaper. Vacuum up all the dust, wipe down with acetone, dry, and then re-apply epoxy, and you should be good to go. It looks like somebody flubbed the cleaning when they epoxied that transducer in place.

That looks like a cross member (strongback) of the hull. Do not remove it! It was probably also used in moving the hull during the manufacturing process.

What is with the nuts and bolts in your bilge? REMOVE them.
 
#3 ·
Is there a preferred type of epoxy I should use? Why not a good exterior-grade silicone gel? (Other than that the epoxy is stronger and will probably last longer). The good thing is that this area of the boat is not accessed much.

Yes, the bilge has all sorts of bits and whatnot. I'll bring the shop-vac aboard next time I pull it up to the house for maintenance.

Nah, I'd never even think of removing something that seems to be structural. Whatever it is, it was clearly put there when the boat was made.
 
#4 · (Edited)
I just had the chance to use a bottle of Six-10. I think it's a West System product. It's a two part thickened epoxy that is SUPER easy to use and very strong. You probably won't use much and there's an insert and a nut that go back over the tip to keep intact whatever you don't use. Silicone is just a temporary fix that will cause the transducer to come off the next time you bump it and it will also leave a residue. The recommendation to sand both surfaces is to get a good bonding surface prepped for the epoxy. Once you do this and wet both surfaces, put something hard on top and let sit for a couple of days. Then....you might never have to worry about it again.

Umm, what's the purpose of all that duct tape?
 
#5 ·
No, no, no! Silicone should be illegal
to use on a sailboat.

Try putting the transducer back down
using wax from a toilet bowl ring. Some
people have them permanently affixed
that way. Mine is. As long as it's in an
area that is not accessed it'll stay put.
At least give it a try. Costs about $1.89.

A good cleaner to rid surfaces of residual
stuff is denatured alcohol, not isopropyl,
denatured.
 
#8 ·
Actually, when this type of transducer first became available, silicone was shipped with the transducer for installation. The only problem with silicone is that it has the tendency to hold bubbles, which is a problem with any transducer. Those tiny, almost microscopic bubbles create a huge signal loss. With epxoy, you can use a much thinner layer, which translates to fewer bubbles in the mix.

Gary :cool:
 
#10 ·
I think when the transducer was epoxied, the guy used duct tape to hold it in place, and there was probably no reason to remove it.

All the guidance provided is in line with what I expected. My main question was about the epoxy still stuck to the transducer, and whether I absolutely had to remove all of it, or whether I could sand it smooth. Note the pattern of the fiberglass molded into the dried epoxy.

My other concern is whether there might be some air pockets in the dried epoxy on the transducer, so perhaps I do need to remove it all.

Or can I get a kit that includes the cylinder that I epoxy to the hull, fill with the right liquid and mount the transducer in the "cup"?
 
#11 ·
UPDATE:

I remounted the transducer, placing it a bit further back from where it was previously (where the hull surface seems a bit flatter and where there was not old epoxy to chip off). I sanded and cleaned the hull surface, got all the old epoxy off the transducer and roughed it up slightly with sandpaper, and cleaned both surfaces with Isopropyl alcohol (didn't have denatured alcohol on hand). I used JB Weld Marine Epoxy.

Installed Friday evening, and we took the boat out to Jordan Lake on Saturday afternoon. The Raytheon depth/fish finder worked great.

Thanks for all the input. I feel better having used epoxy in lieu of silicone.
 
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