transducer sealant question
 

I want to permanently mount my transducer. This involves a couple of sheet metal screws thru my aluminum transom. What is the recommendation for a sealant, and do I just apply it to the screw and screw in? Thanks.

i just pre drill the hole, then add some clear silicon or marine goop into the holes prior to putting the screws in. Then just whip off the excess silicon that comes out.

Some silicone behind something like this.

https://www.cabelas.ca/product/10099...mounting-plate

If you are frugal, you wouldn't be the first guy to use a piece of treated wood.

I'd also recommend getting the mounting plate, and using a pile of marine silicone to seal it.

I would suggest a dense plastic mounting bracket glued to transom with the proper adhesive / sealant. Any Industrial plastic / adhesive store should be able to supply both. If you are coming by SE Calgary I can give you a piece of plastic and the adhesive (assuming it is still pliable and I can find it!!!).

The big advantage is that if you change sounders, mount transducer in wrong spot, damage transducer, tear it off on beaching etc. you can make changes without any holes in transom.

3m 4200 Marine and a mounting plate if someday you may want to remove it.

3m 5200 Marine and a mounting plate if you do not ever intend to remove it.

Already been said if you mount a plate you can move or add transducers(good advice).

Can get 3m marine at Canadian Tire.

4200 has 1 in stock in Medicine Hat.
5200 has 6 in stock in Medicine Hat.

https://www.cabelas.ca/product/10099...mounting-plate

Shows in stock.

And you can also add a couple screws if you wish.

PS - I used a couple of screws plus the 4200 and it was still not easy to get off after I got the screws out.

Marine Goop is the best. A small blob over the hole before you put the screws in, assuming you are pre drilling. If not, around the screw head after.

If you are storing this boat out side or just under cold storage.
The transducer may fail if the temp. drops below -40 c
I now remove my transducer ever year from my boat.

Your transducer must of got bumped, cracking the plastic when cold.

i used a puck board same material as hockey rink boards glued it to the transom of the crestliner mount transducer with screws just in the puck board no need to drill holes in boat that will eventually leak . it has be a few years now and no problems

I have lost two because of the cold and i know a few other guys also that got broken.
Its been a few years since it got below -40
Just not taking any more chances

Like others have said - I strongly recommend mounting a plastic/marine board to the transom area where you intend to mount your transducer.

The plate mounts with a couple small screws and some marine sealant/glue like 5200 3M.

I've used 5200 on numerous applications below the waterline on numerous boats and have never had so much as a single drop of water in there. It creates a permanent waterproof seal.

At some point you will either want to adjust your transducer location or height and likely change out and/or upgrade your transducer and securing into a board (and not drilling more holes into your boat) is the way to go.

Do it once - do it right. Don't poke any more holes in your transom than you need to.

I picked up a small solid plastic type material plate at Bass. Came with a 2 part epoxy that was very easy to work with , no holes drilled into the boat, just the plate. Went on easy and holds like it was screwed on. Best of all no drilling into the boat. Cost was around 40 bucks.

Buy a plastic cutting board or puckboard mount the board vertical with transducer bolted to the cutting board. You only drill a couple holes on the top of the board in the overwash area but the transom. No need to drill holes below the water line.

I was ready to dismiss the mounting board idea as I cannot see ever moving the transducer and it would require holes anyway. But I did some snooping and there was a guy that epoxied the mounting board to the transducer. It would be smart to have a board there just in case. He cut key's in the board with a dremel. I have a key cutting bit for my router table and am thinking of cutting some key's in a cutting board cut to size and epoxying it to the transducer. Thoughts?

Buy a plastic cutting board or puckboard mount the board vertical with transducer bolted to the cutting board. You only drill a couple holes on the top of the board in the overwash area by the transom. No need to drill holes below the water line.

You won't know if you need to move the transducer until you have mounted it and taken the boat out for a spin.

Keep in mind it's not uncommon to have to move it higher/lower or left/right to get consistent readings. To me, to risk drilling yet another 2-3 holes in your transom to re-position your transducer when you could have used a board is senseless.

Also, what happens a few years down the road when you upgrade your fish finder and need a different transducer?

Or what happens if you smack your transducer and it bends the screws and opens up your holes?

I'd say, and I'd insist, you buy the $20 board.....and do it right. Friends don't let friends do it wrong.

Keep in mind - with a board all you need are screws the correct length to penetrate the board but not too long as to pierce your transom. There will never be a need to drill another hole in your transom - and, as other have mentioned, you can glue it on or use a longer board and screw it above the water line.

You may want to change the transducer sometime, add another fish finder and a second one. Glue the board on then screw to it.