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Thru hull transducer leak
Posted: September 22nd, 2025, 12:48 pm
by Merkinbrumsky
So there are a couple of old thru hull transducers in my bilge that look like they are from the Stone Age. Neither functions at this point and I have already replaced the old electronics. I noticed on the weekend that one of them has a small weeping leak. They both appear to be threaded into a sleeve that’s epoxied into the hull. I was able to hand tighten the leaking one a half turn but it didn’t completely stop the leak. What ‘a my best course of action here? Boat will be pulled in a month or so. Remove and replace o rings? Can you purchase a blank for the hole and lose the old ducers? Clean and apply sealant? Pull them both and glass over? I should have taken some pics. I think they are from an old depth/speed log. Likely from mid 80’s.
Thanks
Re: Thru hull transducer leak
Posted: September 22nd, 2025, 1:48 pm
by km1125
I'd be a bit wary of cranking down on old plastic parts that are below the waterline in an attempt to stem a leak. The best way would be to remove it, coat with something like 4200 and reinstall and tighten "snug" (not overly tight to strain the plastic). But I'd probably only do that if I actually had to use the old part. There are some blanks out there that can be used to close-off a hole that's been previously used, but I don't have a quick link to point to. You can also add an appropriate thru-hull and just cap it inside the boat.
Re: Thru hull transducer leak
Posted: September 22nd, 2025, 2:01 pm
by Merkinbrumsky
km1125 wrote:Source of the post I'd be a bit wary of cranking down on old plastic parts that are below the waterline in an attempt to stem a leak. The best way would be to remove it, coat with something like 4200 and reinstall and tighten "snug" (not overly tight to strain the plastic). But I'd probably only do that if I actually had to use the old part. There are some blanks out there that can be used to close-off a hole that's been previously used, but I don't have a quick link to point to. You can also add an appropriate thru-hull and just cap it inside the boat.
Thanks, ya…I was nervous about tightening that as well but I didn’t have to really crank on it. I would say I just snugged it up lightly hand tight without much effort. I’m sure if I cranked on it I could snug it up more but I thought better of it.They do have “wings” on either side to hold onto with tightening/loosening arrows and specific directions to not overtighten. I can’t seem to find a pic of a similar one online. Once the boat is on the hard I will dig further.
Re: Thru hull transducer leak
Posted: September 22nd, 2025, 3:02 pm
by Merkinbrumsky
Data log head
Re: Thru hull transducer leak
Posted: September 22nd, 2025, 5:21 pm
by bud37
My opinion , if you are going to fix that, then take the time and do it right, fill the holes properly after checking for any water intrusion in the glass like was mentioned, then it won't come back to bite you while you are not looking.
Re: Thru hull transducer leak
Posted: September 24th, 2025, 6:28 am
by km1125
That looks like an old DataMarine, either speed/log or depth.
Re: Thru hull transducer leak
Posted: October 1st, 2025, 6:43 pm
by Merkinbrumsky
You win!!! lol..,datamarine depth sounder