Grease Mount Transducer to Inside of Hull

[sdowney717]

I was thinking of this very thing and it looks like it works.
Transducer Grease Mount - Kayak Fishing Adventures on Big Water’s Edge

I got a used 320c Eagle fish finder and transom transducer.
I placed transducer into the bilge rain water and it reads the depth ok in the slip with the transducer screwed to a floor support (wood boat term).
I vacuumed out all the bilge water to get a dry hull to work with.

I plan to :
cut a 4 inch pvc pipe at 15 degrees to match the hull angle,
slip under transducer
glue the PVC pipe to hull using PL premium poly roof sealant black color
pack pipe with waterproof lithium marine grease
push transducer into grease

should work as apparently it shoots through grease like it is water.
saves the trouble of haul out to put in another deth sounder transducer.
That site says it pings to the depth it is designed to do.

Needs to be waterproof lithium based grease as that wont wash away.
I was wondering if some other slurry could work besides grease.

[capngeo]

Ive tried temporary mounts to check for turbulence with nothing but dish soap!

I’d be careful of the roof sealant, as it might not be a good acoustic conductor (rubbery when dry?) I’d use epoxy instead. Just curious, why not just glue down the ducer?

[sdowney717]

the black roof sealant is just holding down the edge of the angled PVC pipe to the hull.
the grease will go right down to the the hull

I dont want to glue it as that would take a lot of expensive epoxy and is too permanent. The PVC pipe I have, the black PL I have. I just need to get a cartridge of lithium moly grease from walmart.

[Pete7]

Just glue it in with sealant. I did a transom transducer inside the club dive rib in 1997, its still there and working.

If you use epoxy and it will work if thickened, then make sure you don't mix any air bubbles in it as it is stired together.

Pete

[capngeo]

Actually, for the price of the grease alone, you can get small tubes of epoxy... your level of permanence is directly proportionate to how you prep the hull. Not to mention not being as messy as having the grease. FWIW, if you want to use the PVC, just fill it with glycerine... then cap the tube to keep out dirt etc. I know in the OP you asked about grease, and yes it will work.... But I wouldn’t go that route

[zeta]

toilet ring wax works well for me.

[capngeo]

Only problem there is that the wax will not allow for any movement while connecting the fasteners, and will break the acoustic couple

[sdowney717]

perhaps slightly heat the wax and pour it in
that toilet wax ring melts easily with tiny amount of heat.

Only thing is I would not want much heat on the transducer.
about 100 degrees and that stuff gets soft like soft butter.
I am using the transom mount transducer, so it has a bracket and with that attached, I can pull the transducer up and down.

A cartridge tube of lithium moly grease is only a few dollars at wally world.
You dont need marine grease, just grease with a lithium base. Lithium base greases dont mix with water and wash off.
Regular grease will mix with water

[capngeo]

Do as you want brother.... as they said in the yard I used to work in.. “I can’t see it from my boat"

[Reefmagnet]

Sikaflex works a treat. Just put a glob down and work the transducer into it to make sure no air bubbles get trapped. Easy to do and can be removed without too much hassle. I moved a transducer from an oil filled box to a sikaflex bed once and there was no perceivable difference in performance. It pays to do a dummy run first, however, using ky or the like to make sure there is nothing inside the hull that will obstruct the signal.

[sdowney717]

Sikaflex, is that the fairly soft rubbery stuff?

[Reefmagnet]

Yes it is

[zeta]

Originally Posted by capngeo

Only problem there is that the wax will not allow for any movement while connecting the fasteners, and will break the acoustic couple

I only use the wax for temp install, no fasteners, I press transducer into the wax placed on the boat. Seems to work okay.

[sdowney717]

I cut an angled piece of PVC pipe and glued the pipe to the hull
Next step is to put some toilet seal wax since its cheaper than grease I think I will try it.
The transducer is mounted and will just pivot down into the stuff.


I glued it down using PL polyurethane roof sealant black color, good stuff.

[sdowney717]

it works perfectly fine using the toilet bowl wax rings.
just get the cheapest wax rings.
pack wax into the cavity solid make sure no air entrapped in wax. then press transducer into the wax and smooth it all round.
the wax is very soft and heat even from your warmed hands makes it partially melt.
Does the sound energy from a transducer create heat? likely not enough power to melt the wax.