Thread: Transducer mounting plate

There are no screws thru the board and into the hull, just 3M Marine 5200 Adhesive/sealant. Used acetone to wipe off both the spot on the hull and the back of board then put a nice layer all over the back of the board and then tape in place. I think you need to let adhesive cure for 5 days.

I don't know exactly what is on the garage floor but it is some type of coating. Was done before I bought the house. The floor is not as neat as it looks in this pic. Very faded where it gets traffic and slicker than snot when it gets wet.


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I did the exact same thing as marine4life back in February. Spent a lot of time on the water and made some long trips down the interstate with no issues since then. I used the fast cure 3m 5200 marine adhesive. Cures in 12 hrs I believe. No holes in the hull.

Having it set back like that are you better able to keep it reading while on plane? Mine loses bottom when I run.

Mine does not read at high speeds but I have it that way on purpose. I use the in dash lowrance when I need the high speed read and that TD is set about 1/2 inch below the hull and angled for straight down when on plane. The HB SI transducer is slightly above the bottom of hull to help protect it and I have it angled back up pretty high to get the best side imaging while at idle speed. There is a YouTube video that shows how to set the angle to ensure it looks straight down while boat is moving slowly using a level and handful of change. This is the only boat I have set up so my knowledge is limited but I followed all the guidance I received or could find on here.



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I have been researching this for mounting my new Helix 5 SI transducer on my 1648 flat bottom. Going with no screws and 3M 5200 is a fine method, however, most of the advice I have read said it works best if the boat transom mounting location is coarsely sanded then wiped with acetone. It's also recommended to even "mill" (prob not the correct term) out some grooves/pockets in the cutting board for better adhesion.

Originally Posted by scout-j-m

I have been researching this for mounting my new Helix 5 SI transducer on my 1648 flat bottom. Going with no screws and 3M 5200 is a fine method, however, most of the advice I have read said it works best if the boat transom mounting location is coarsely sanded then wiped with acetone. It's also recommended to even "mill" (prob not the correct term) out some grooves/pockets in the cutting board for better adhesion.

I did scuff the transom and prep it with acetone but I did not put grooves or holes in the cutting board. I've been pleased and kinda surprised so far because that 3D structure scan ducer is pretty heavy. I'd guess 18 ounces or so.

I've never been a big fan of the smaller mounting plates. I prefer the bigger ones myself. Unfortunately, Cabela's stopped selling the larger ones. We actually purchase oversized cutting boards and cut them down.

I simply do not trust the adhesive.

The picture below shows the boards that we use and the size of them. If there are any rivets or anything where the board goes, we recess the board before installation. This photo shows the side image transducer on the outside. I was tired that night and placed it to the inside the next day when I found the error of my ways. All screw holes are above the water line (total of 5 stainless screws). A small amount of marine grade silicone is placed on each screw. In the event you are going over existing holes, recess the board really well, insert a screw with silicone to plug the hole, and then fill the recess with silicone before installing the board. No need to put silicone around the board.

My fish finder reads bottom at 45mph. IF adjusted correctly, you shouldn't lose bottom.