Plug thru hull hole left after transducer removal.

[Bill Curtis]

How would one go about plugging the hole in the hull left after removing a simple low profile thru hull sonar xducer?

The xducer is plastic and original to the boat from the OEM for the Lowrance 3500 depth sounder.

There is a small chip on the leading edge of it and am concerned the whole thing may be compromised.

The problem is that is it is nearly impossible to get to from the inside , as it is under the engine in a horrifically tight engine compartment. Needs engine to come out to fully access, which I do not want to do right now. Thinking about Marine Tex'ing it, for now, from outside and dealing with permanent fiberglass fix when it is time for engine removal.

Reasonable suggestions???

Replacement xducer no longer available for the Lowrance 3500, so as soon as I find something to fill the dash spot for the Lowrance sonar, I will place the 3500 on here as a "free to good home that needs it, not to just resell for a profit". Or maybe a trade for a raw water pressure gauge to match rest of my Sierra Sahara gauges.

 

[Golfman25]

What I did was replace with a thru hull fitting the same size as the hole and then screwed a cap on it. Marina filled is with silicone sealant just to be sure. Worked for several years until I reused the hole for an AC water intake.

 

[Lazy Daze]

Inspect that "chip" better. It may be just fine - don't assume. You may very well be able to just leave it as is. IF it is compromised, I would NOT try to just put a bandaid on it with MarineTex (or anything else). It would be exactly that... a bandaid...and bandaids don't stay on long in the water.

But... if you wanted to do a bandaid... a waterproof one ... glass over the entire thing. Sand/prep the gelcoat and ducer... use some thickened epoxy to fill gaps and then a couple layers of glass. Sand/smooth the final layer and then coat again with epoxy. This bandaid will need to be, probably, about 12" square.

 

[Bill Curtis]

Inspect that "chip" better. It may be just fine - don't assume. You may very well be able to just leave it as is. IF it is compromised, I would NOT try to just put a bandaid on it with MarineTex (or anything else). It would be exactly that... a bandaid...and bandaids don't stay on long in the water.

But... if you wanted to do a bandaid... a waterproof one ... glass over the entire thing. Sand/prep the gelcoat and ducer... use some thickened epoxy to fill gaps and then a couple layers of glass. Sand/smooth the final layer and then coat again with epoxy. This bandaid will need to be, probably, about 12" square.

Thanx for the input.

I am not concerned that it will fail entirely and "pop out (or in), as the fairing flange on it is 98% intact. My concern is that chip may lead to a small water leak around the sender, on the leading edge, hence the marine tex to put the fairing back onto the flange, just to ensure water tight integrity around the sender..

Will be pulling boat partially off trailer this week to inspect the xducer.

 

[dwna1a]

Bill, any chance you can post us a photo including the chipped area?

 

[ttmott]

I had a thru-hull transducer removed and the hole filled and plugged. It was right on the keel. The build there must have been two inches thick. They cut a fiberglass plug and epoxied that in place then ground it all down and laid up probably ten layers of glass both inside and then outside. Then on the outside gelcoat, barrier paint, and bottom paint. Inside they sanded the entire area and coated with Bilgecoat. There is no coring in the hull on my boat BTW.

 

[Lazy Daze]

Thanx for the input.

I am not concerned that it will fail entirely and "pop out (or in), as the fairing flange on it is 98% intact. My concern is that chip may lead to a small water leak around the sender, on the leading edge, hence the marine tex to put the fairing back onto the flange, just to ensure water tight integrity around the sender..

Will be pulling boat partially off trailer this week to inspect the xducer.

The transducer seals into the hull fitting with o-rings. I can't imagine how what you are describing would ever lead to a leak. But you could put some LifeCaulk on/in it and smooth it down flat.

For anyone reading through this... look again at TT's post... THAT is the correct way to fix a hole. Note in his description that it was fixed from both the inside and outside.

 

[Bill Curtis]

Bill, any chance you can post us a photo including the chipped area?

Not yet. Boat is too close to ground, while on trailer, for me to get under there to look.. I felt it while reaching under there probing around with my hand.

 

[Bill Curtis]

The transducer seals into the hull fitting with o-rings. I can't imagine how what you are describing would ever lead to a leak. But you could put some LifeCaulk on/in it and smooth it down flat.

For anyone reading through this... look again at TT's post... THAT is the correct way to fix a hole. Note in his description that it was fixed from both the inside and outside.

Do not believe it is a sleeve type thru hull. Think it is the old style threaded xducer that has the treads on it, held in by a big ol nut inside the hull.