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crabbypatty

Transducer mounting

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I have a new fishfinder and the new transom transponder bracket is different than the old one. frown.gif

I need to remove the old aluminum bracket and drill some new holes in the transom of my 16' bluefin tinny.

How do I patch the old holes, and how should I seal the new ones?????confused.gif

 

I could do pics.... if need be

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What you can do is fill the holes with marine silicone, then mount this on your transom.

 

http://www.************/cabelas/en/t...233&hasJS=true

 

Cabelas sells them, the can be cut to any size and never again put holes in your transom no matter how many transducers you replace. I had it on my old boat for over 10 years and insisted one be put on my new boat when then installed the transducer.

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fill the holes with MarineTex and put a coating of Marine silicone under the new bracket making sure to cover the old drill holes. will be sturdy and dry.

You don't want water wicking between the gel coat and inner layers, especially any wood in the transom.

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The previous 2 posters referenced marine silicone, possibly in error.

 

Read the packaging and you will see that marine silicone is not for use below the waterline. Silicone has a very limited lifespan, especially if exposed to sunlight.

 

For below waterline use a poly-sulfide such as Boatlife or 3M 4200/5200. These clearly state they can be used both above and below the waterline. Use 4200 if you think you may want to take it off in the future, 5200 if you intend it to be a permanent attachment. 4200 is as good a caulk as 5200, but 5200 has amazing adhesive quality as well as serving as a caulk.

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What I've done before -

Mount a appropriatly sized piece of 3/4 cabinet grade (and painted) piece of plywood using the original mounting holes. Flat head SS and sealer (like Boatlife). Then mount your new mount to the plywood.

 

I hate adding new holes. cwm27.gifwink.gif

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Assuming there is plywood behind the aluminum transom, fill the old screws with 5200 and drill new holes for the transducer, coating the screws with 5200. Also squeeze some into the new holes. Contrary to what folks say, screws bedded with 5200 are easy to remove. You don't need to coat the entire bracket, just the screws

If you don't mind the look, the easiest and best way to seal the old holes is to reuse the old screws, again coated with 5200, and leave them in place.

Be wary of Marinetex on aluminum. They have different expansion and contraction rates and the fillers will loosen up.

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My link in the other post didn't work, I"ll try to explain. You can either buy a piece of HDPE (3/4" or 1" thick) or buy the piece that Cabelas sells (made of HDPE also), fill the existing holes with 3M 5200 as GBCapt suggested, then cover those holes with the piece of HDPE. Use more 3M 5200 and 4 screws to secure it. This will last forever and any future holes for transducers will be in the HDPE, not your transom. Here are some pictures of my boat with it.

 

Transducer004.jpg?t=1277467199

 

Transducer001.jpg?t=1277467059

 

Transducer003.jpg?t=1277466919

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What he said, except I just glued a scrap piece of mahogany with 5200 to avoid drilling any holes. If I already had holes drilled as you do, I would use them to screw a piece of starboard (HDPE) bedded in either 4200 or a polysulfide caulk like Boatlife. Silicone (marine or otherwise) is a mistake below the waterline; it will fail in time. No need for 5200 in this application; that stuff will be there long after even a tin boat has corroded into dust!

View PostWhat I've done before -

Mount a appropriatly sized piece of 3/4 cabinet grade (and painted) piece of plywood using the original mounting holes. Flat head SS and sealer (like Boatlife). Then mount your new mount to the plywood.

 

I hate adding new holes. cwm27.gifwink.gif

 

 

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View PostAssuming there is plywood behind the aluminum transom, fill the old screws with 5200 and drill new holes for the transducer, coating the screws with 5200. Also squeeze some into the new holes. Contrary to what folks say, screws bedded with 5200 are easy to remove. You don't need to coat the entire bracket, just the screws

 

If you don't mind the look, the easiest and best way to seal the old holes is to reuse the old screws, again coated with 5200, and leave them in place.

 

Be wary of Marinetex on aluminum. They have different expansion and contraction rates and the fillers will loosen up.

 

cwm15.gifcwm15.gif

 

 

only thing different is use West system G/Flex to fill the holes smile.gif

 

 

View PostMy link in the other post didn't work, I"ll try to explain. You can either buy a piece of HDPE (3/4" or 1" thick) or buy the piece that Cabelas sells (made of HDPE also), fill the existing holes with 3M 5200 as GBCapt suggested, then cover those holes with the piece of HDPE. Use more 3M 5200 and 4 screws to secure it. This will last forever and any future holes for transducers will be in the HDPE, not your transom. Here are some pictures of my boat with it.

 

 

Transducer004.jpg?t=1277467199

 

 

Transducer001.jpg?t=1277467059

 

 

Transducer003.jpg?t=1277466919

 

so you drilled 4 holes instead of 4? cwm13.gif

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