[twowheels1]

Hi all...probably not the first to ask about this but couldn't find an answer in the forum.
I have a Beneteau First325 and am replacing depth, speed, and wind instruments. Pulled old thru-hull transducers and found that the new transducers are 1/8" smaller in diameter. Was considering building out the extra 1/8" by laying layers of fiberglass and resin on inside of hole walls...figured a few layers would probably build out the 1/8" I need. I'll be using the West Marine sealant(their version of 3m 4200) to seal the flange to the underside the boat and then fill the threads of the transducers with the sealant as per instructions.

Thoughts?

 

[twowheels1]

Thanks for all the feedback. I ended up laying a few layers of fiberglass mat and resin across a few days. Sanding between layering. It seems to have worked. I got the hole down to a diameter where the transducer housings fit snugly. Used the West Marine sealant on inside of flange of housing on outside of boat with LOTS of sealant up the threads of housing. I forced some sealant from inside the boat down into gap between housing and hull. Really no gap to speak of but we all know how that water will find it's way.
It seems to have worked out well. However(BIG however) the boat doesn't drop until next week. I'll be onboard with fingers crossed when it does.