Marine Glue for fishfinder transducer mounting on transom

Hello Everyone,
Instead of drilling holes on transom for mounting a fishfinder transducer, is there any good marine glue that I can use to do the task? Many thanks - Anthony

Re: Marine Glue for fishfinder transducer mounting on transom

I suppose 3M 4200 or 5200 may hold, but it's better to just drill the holes. Or mount a piece of Starboard on the transom with 5200 (permanent) and screw the transducer to that.

Re: Marine Glue for fishfinder transducer mounting on transom

5200 won't stick to starboard

Re: Marine Glue for fishfinder transducer mounting on transom

ezmobee said:

5200 won't stick to starboard

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Then epoxy it.

Re: Marine Glue for fishfinder transducer mounting on transom

Old trick for attaching starboard. Cut two shallow dovetail joints in the back of the starboard. Fill the dovetails with 4200 and stick it on back of the boat. Use duct tape to hold the board in place for 8-12 hours.

Easier yet, just drill the two holes in transom required by the transducer mounting plate and install the screws using marine epoxy.

Re: Marine Glue for fishfinder transducer mounting on transom

Sure ... but, if this is your 1st install, I would do it with a temporary adhesive (say, ordinary silicon) until you are satisfied with the location and the performance you get. You don't need to use starboard, there are any number of plastic materials that you can use (polypropylene comes to mind) as your "screw into" mounting plate. Using the supplied screws, mount your transducer bracket onto your custom made plate and glue it onto the transom with the silicon seal or similar removable product. Once you're happy with the location, peel it off, clean the area, and use 5200 for a permanent attachment. Too many people screw their transducers onto their transom, only to later realize they've picked a bad spot ... moving it around several times until their transom looks like swiss cheese. Then they come on here and ask what's the best product to seal up all the holes thy've made. Go figure.

Re: Marine Glue for fishfinder transducer mounting on transom

On my first boat I fretted about adding a screw to the transom for the fishfinder. I hated drilling that hole. Sooo worried...

This boat, I never hesitated drilling two 1 5/8" holes in the transom for underwater lights. Once you've done it and realize by doing it right that you will not sink the boat, you've gotten past the biggest hurdle.

Re: Marine Glue for fishfinder transducer mounting on transom

One of my transducers has been glued for over 10 years and never had a problem. I have also taken it off and move a little one time to make room for another transducer.
I used just plane old marine silicon glue.
The key is your transducer mountaing plate needs to have some flat area and be made of something that the glue will stick to.
Some plastics do not work well with glue.

Before I go any farther I need to give you some very important saftey info.

IF YOU GLUE IT ON YOU MUST HAVE A TIE WRAP STRING OR SOMETHING THAT GOES AROUND THE TRANSDUCER CABLE AND IS FASTEN TO SOMETHING SOLID AS CLOSE AS POSSIBLE TO THE TRANSDUCER.

If it should come loose at speed what will happen is the water will push the transducer to the stern at high speed then the cable will swing the transducer up and around and in to the stern of the boat and KILL your passanger riding there when it hits them in the head. The tie wrap stops it from swinging into the boat.

If you mount it on a small aluminum plate the glue stick to very well it will not come loose if the glue also sticks to the boat.
In my case the boat is painted aluminum and the metal transduer bracket sticks to the glue also. I have hit sticks and the transducer pop up like it is suppost to. Then you just loosen the mounting screw and move it back into position.

I done this with a small 20 degree 200khz transducer. I also do the same with my Large 8 degree 200khz transducer but I mounted right next to my Pitot tube and they share one screw.

Re: Marine Glue for fishfinder transducer mounting on transom

Okay, here is my update... I mounted the transducer on a AL plate then glued it on the transom using 3M 4200. It seemed very solidly glued. I also tied the cable using cable clamps. It looks very good so far. Thanks so much for all great feedback!!!

Re: Marine Glue for fishfinder transducer mounting on transom

How fast a boat and how large of a transducer, and in your case, how large of an aluminum plate? At 20-30mph I've seen them rocket out of the water. Most bass boats, when the tranducer comes off there is only a piece of cable left. I'd put at least two screws through that alum plate and seal with 5200. But thats me.

Re: Marine Glue for fishfinder transducer mounting on transom

I got a 17 footer Maxum with Force 120 outboard. After letting the glue cured for almost 24hrs, I took it to the river to test the fishfinder. It's working great. The fishfinder and the OLD Depth Finder both showed the same numbers. It did show fishes but I didn't do any fishing. While the fishfinder seemed to work great, but I got water flashed up at high speed.

Re: Marine Glue for fishfinder transducer mounting on transom

Tilt the transducer up a tad or move it vertically a touch. This is the reason for slots on the mounting bracket of most transducers. You will likely get some roost from just about any transducer, but it is something that can be dumbed down with adjustment.

Re: Marine Glue for fishfinder transducer mounting on transom

anple said:

While the fishfinder seemed to work great, but I got water flashed up at high speed.

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Define "seemed to work great." If it truly is, leave it alone and don't mess with it.

Re: Marine Glue for fishfinder transducer mounting on transom

I have settled with the location to mount the transducer. The attached image/link should describe how I did it. The water flashing problem is also gone...

Re: Marine Glue for fishfinder transducer mounting on transom

I thought your wanted to avoid putting holes into your transom ... oh well.

Re: Marine Glue for fishfinder transducer mounting on transom

Those are existing holes....

Re: Marine Glue for fishfinder transducer mounting on transom

Most just screw the transducer mount to the transom with a bed of a removable polyurethane sealer, like 3m 4200. A little extra sealer forced into the pre drilled screw holes helps seal it. If it has to be moved, the screws can be backed out and the mount pried off, cleaned up, and do it again, any number of times. Usually only takes one or two tries. It really ain't rocket science to get the skimmer skimming.

I've pulled them off, and if poly sealer is used, never found any water behind them. Silly cone is another story. It usually fails in a year or so.

Re: Marine Glue for fishfinder transducer mounting on transom

What actually will "cutting dovetails" in the back side of Starboard, or any other poly plastic, accomplish for an adhesive that has negligible adhesion on a substrate it won't adhere to anyway? I have seen that "suggestion" posted many times and the only formidable conclusion I can think of is that you might create more surface area on a substrate that the suggested adhesive will not adhere to in the first place.