My 1983 Hunter 34 sailboat has a small leak somewhere around the depth finder transducer. The leak is about a tablespoon a day and I cannot tell exactly where it is coming from. I am attaching a picture. It looks like the entire transducer is glassed in. Thoughts? Is this a big concern? The boat is currently in the water. Many thanks!
Small leak around depth transducer on old sailboat.
- Thread starter JohnnyP
- Start date
It was common back then for manufacturers to use round disc of wood as backing plates. A previous owner may have also. In time the wood gets wet, rots and leaks. Could be the black material around the base of the valve?
The large round area of fiberglass makes me wonder if a PO removed a transducer, repaired the hole and drilled for a new transducer.
A big concern? It's not going to get any better and probably will get worse. Will it fail catastrophically? Probably not. Should it be fixed? Definitely. Any below the water line leak would be first on my priority list.
The large round area of fiberglass makes me wonder if a PO removed a transducer, repaired the hole and drilled for a new transducer.
A big concern? It's not going to get any better and probably will get worse. Will it fail catastrophically? Probably not. Should it be fixed? Definitely. Any below the water line leak would be first on my priority list.
As @Ward H said it appears the installer used a wooden backing plate that was glassed over. A proper fix is to remove the transducer, remove the old sealant, inspect the backing plate, and reinstall. Do not use 3m 5200 or a polysulfide caulk. If the backing plate is waterlogged or rotted remove it. It is not necessary to have a backing plate for this through hull. This a job that can only be completed on the hard.
The caveats, if the original installer used 5200 it is likely the transducer will be damaged while trying to remove it. It is not repairable. Airmar makes transducers for most electronics companies, they may have a replacement. If not ask Santa for new instruments.
Any attempt to seal the leak from the inside with more caulk will be a short lived solution.
The caveats, if the original installer used 5200 it is likely the transducer will be damaged while trying to remove it. It is not repairable. Airmar makes transducers for most electronics companies, they may have a replacement. If not ask Santa for new instruments.
Any attempt to seal the leak from the inside with more caulk will be a short lived solution.
Interesting. I saw the fiberglass that the transducer is sitting in, and thought it looked as though the Hunter wooden backing plate had been removed, and the installer had properly constructed a solid glass area to drill for the transducer.
I am not disagreeing with you, only interested in our different takes on the glassed area.
Everything you've posted is spot on, as far as I can see, from here and the picture.
I had that problem. I found that the nut was cracked. I removed the boat from the water and installed a new transducer with 4200. No more leaks. Do not overtighten the nut, just snug tight is all that is needed. Backing plate is not needed as mentioned above.
I agree that some sort of backing plate is glassed to the hull, but the transducer is still held in place with a nut and sealant. Remove the thru hull, inspect the backing plate, and rebed the transducer. All should be good.
Like @JoeWhite said, be careful with the nut especially if it is plastic.m I also cracked one trying to fix a mid-season leak. I freaked out waiting for a new nut to show up…kept me awake at night thinking that the transducer was going to fall out. It didn’t, and I got the new nut on, and slathered some sealant under the gasket before I put the nut on. Made it through the season, and then fixed it right after I hauled out at the end of the season.
Greg
Like @JoeWhite said, be careful with the nut especially if it is plastic.m I also cracked one trying to fix a mid-season leak. I freaked out waiting for a new nut to show up…kept me awake at night thinking that the transducer was going to fall out. It didn’t, and I got the new nut on, and slathered some sealant under the gasket before I put the nut on. Made it through the season, and then fixed it right after I hauled out at the end of the season.
Greg