Transducer mounting

I'd like to mount something to the back of my transom to mount transducers to without more mounting holes thru the aluminum. I thought I once saw a post that talked about using kitchen cutting board material (plastic) but none are thick enough. Suggestions for material to use and methods of attachment would be appreciated.

'98 Lund Explorer w/ 50hp Merc 4c (Yamaha) carburetored NO torque motor

I guess you mean you want to glue a solution to the hull?

I didn't for a few reasons...

In the event I wanted to move the transducer up, down, port or starboard, if the transducer broke, if I wanted to change the DF and needed a new transducer, the cement failed, or I wanted to move the transducer to another boat.

All unlikely but I wanted a removable solution without holes below the waterline, above waterline holes are easily repaired.

So I resigned myself to three holes shown in the pic below. What you can't see is on the back surface of the mounting plate I routed in vertical slots for the SS nylock nuts so I could move the transducer around if needed. I did not use wood type screws because I thought they might loosen over time.

I also trimmed the length of the mount so I can still use the rear handle.

At any rate, the plate I got at bass pro for $20 is more than thick enough:

https://www.basspro.com/shop/en/transducer-mounting-plate

I went a different route. I use a Tite-lok clamp on transducer mount. This way I can clamp it anywhere I want on the boat based on where/how I'm fishing at the time. It's also handy for ice fishing. The sonar screen and small 12 volt battery are housed in a small hard plastic base and frame with soft sided exterior portable sonar carrier that Cabelas used to sell. Works fantastic. I spent the money on one great sonar ( at the time ) and made it portable/adaptable instead of buying two sonars and hard mounting them. Just a thought.

my boat came with the mounting block already attached.maybe a trip to your nearest boat chandler would help in sourcing one.

Bass Pro sells a transducer mounting plate that I used, it was only $20. It's bolted but only two bolts and I can move or re-install my transducer as much as I want without drilling through the hull.

The material is called HDPE. You can buy it online in custom sizes or can buy it at home improvement stores in the form of decking boards. The ones specifically made for a transducer on a boat though can be found though for about $20. When I did mine I used one I got from Amazon, ran a router down the back to give more for the adhesive to grab, and then glued it on with 3M 5200. I used scrap lumber and clamps to hold it snug to the transom while it cured. It went ok but looking back it would have been nice to have used a dovetail router on the back instead of the basic bit. I also did not sand the gluing location down to bare aluminum as I now know I should. And finally, I should have taped off the edges for easy cleanup....I was just going to scrape away any 5200 that oozed out but it doesnt like that very much. Better to tape it off and peel off as soon as you get it clamped up.

wmk0002 said:

The material is called HDPE. You can buy it online in custom sizes or can buy it at home improvement stores in the form of decking boards. The ones specifically made for a transducer on a boat though can be found though for about $20. When I did mine I used one I got from Amazon, ran a router down the back to give more for the adhesive to grab, and then glued it on with 3M 5200. I used scrap lumber and clamps to hold it snug to the transom while it cured. It went ok but looking back it would have been nice to have used a dovetail router on the back instead of the basic bit. I also did not sand the gluing location down to bare aluminum as I now know I should. And finally, I should have taped off the edges for easy cleanup....I was just going to scrape away any 5200 that oozed out but it doesnt like that very much. Better to tape it off and peel off as soon as you get it clamped up.

Click to expand...

This method eliminates the need to drill into the transom to mount the block.

X2 on the dovetails (or drill several holes). HDPE is not glue friendly. This gives the glue something to bite or grab onto.

On my saltwater use boats I glued a piece of mahogany to the transom, then epoxy coated it, worked slick!

Here’s what I do on my tin boats = https://www.forum.tinboats.net/viewtopic.php?f=3&t=40648

I have an HDPE mounting block called Stern Saver available in two sizes in several different colors (I got the small one in white)
Been very happy with it.

The Stern Saver comes with a two part epoxy designed for HDPE

The Stern Saver design has wells (where you inject the epoxy) cut out in the back that enhance the adhesion

Sanding the back side of the stern saver and the wells and sanding down to bare aluminum then cleaning the areas with either alcohol or acetone will enhance the adhesion.

uttexas said:

The Stern Saver comes with a two part epoxy designed for HDPE

... and sanding down to bare aluminum then cleaning the areas with either alcohol or acetone will enhance the adhesion.

Click to expand...

You forgot to add ... AND cause the aluminum to corrode. FWIW the curing agents in most of those super adhesives, while compatible with super plastics, will corrode BARE aluminum.

DaleH said:

uttexas said:

The Stern Saver comes with a two part epoxy designed for HDPE

... and sanding down to bare aluminum then cleaning the areas with either alcohol or acetone will enhance the adhesion.

Click to expand...

You forgot to add ... AND cause the aluminum to corrode. FWIW the curing agents in most of those super adhesives, while compatible with super plastics, will corrode BARE aluminum.

Click to expand...

Yup, that's why I opted to bolt mine. People freak out about holes in a boat hull.. if it's done right it's no issue.