# Galvanic corrosion on transom



## Gottagofishn (Nov 18, 2009)

I have a 1997 pro V Se Lund, 17' that has been garaged since I bought it new in 97. I noticed that there was a bubble under the paint on the starboard side of the transom last year. I popped the bubble and painted over it. As I was getting the boat ready this year I noticed another bubble and investigated further. After picking the paint off of the bubbles, I found Pitts all the way to the wood. There are three the largest about a quarter inch in diamater. 
I do take some water into the bilge when boating in rougher water and it probably stays pretty damp there all season. I suspect that water is the cause and would not be surprised to find that the wood has degraded in the transom. 
At any rate, I need to get this repaired. Paul's marine suggested a body shop?!

Does anyone know of a shop that would take a serious look at my Lund? I will travel anywhere in Ohio to get this resolved.

The other question would be, is it worth replacing the wood in the transom? Can it be done at a reasonable cost or should I just be shopping for another boat?


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## I Fish (Sep 24, 2008)

This might be something you want to do yourself. It shouldn't be too bad. I would be concerned with the corrosion, as it almost sounds like there was something on the metal that was then sealed in, either by the paint, or, the transom wood. I'd try to figure out if it's corroding from the outside in, or, the inside out.

You can search iboat.com forums. Likely find the answer to your problems there. http://forums.iboats.com/forum.php 

If you do it yourself, seriously look at using Coosa Board Bluewater 26 instead of plywood.
http://coosacomposites.com/bluewater.html
It's easier than plywood to work with, but, it's a little pricey. You'll never have to replace it again, no matter if the skin leaks or not. After doing some both with plywood, then the last one with Coosa, I'll never mess with plywood and resin for a transom again.

Also, where are you located?


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## crappiedude (Mar 12, 2006)

If ya like the boat I would fix it. If you're handy, I would look into fixing it myself. 
Like ifsh said, I would try to find the source or cause of the corrosion. Something somewhere is causing the corrosion to attack your hull especially to that degree, that certainly isn't normal. 
One question, are your electronics or batteries grounded to your hull? They shouldn't be!


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## Gottagofishn (Nov 18, 2009)

I live in Columbus and really don't want to undertake this myself. I wouldn't know where to begin. Of course the other issue is that fishing season is upon us. I would like to get it done as soon as possible. Other than this issue the boat is in excellent shape.
I just had Paul's marine work on the boat and they found that the zinc anode on the motor was loose. They suspected that could possibly be the cause. After reading the forums I'm not convinced. I asked them to check for stray current and they said they couldn't find any. I'm not sure how they checked.
Does anyone know who could undertake this and do a good job? I fish Erie primarily so it needs to keep me floating........

Thanks for any help.


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## chris rab (Jan 4, 2012)

I had this on a boat I owned. The corrosion could have come from moisture being trapped between the transom and the hull, which causes crevice corrosion. Another possibility could be from the hull being made from treated wood ( not as likely). I would look into the transom further see if it needs to be replaced since there has been water intrusion. Now I used a product called marine-tex which is a hard sandable two part epoxy that bonds to aluminum, I sanded it down smooth and painted it. This cost me about 20 bucks.


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## crappiedude (Mar 12, 2006)

chris rab said:


> *I would look into the transom further see if it needs to be replaced *since there has been water intrusion. Now I used a product called *marine-tex which is a hard sandable two part epoxy that bonds to aluminum, I sanded it down smooth and painted it.* This cost me about 20 bucks.


Before deciding that the transom needs to be replaced, I would try to find some evidence that it's bad 1st. Just because it did get wet, doesn't mean it's rotten. Being garage kept it may be in better shape than if stored outside.
Can you get something and poke around and see if the transom is spongy?

I've also used that Marine Tex, good product. I used it to patch a missing rivet on the BOTTOM of my boat last year, so far it's holding up pretty good. Maybe all you really need is to patch the bare spots and keep an eye on it.


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## chris rab (Jan 4, 2012)

Easy way to check and see if the transom is really bad (assuming your boat has an outboard) with the engine trimmed apply some pressure on the skeg and see if your transom will flex, if it does it deffinatley needs replaced. Doubtful that it is that bad since it has been garage kept.


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## Whaler (Nov 16, 2004)

My buddy replaced the wood in his 18 foot Sylvan using marine plywood. He did it all himself.


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## Gottagofishn (Nov 18, 2009)

Man, I doubt I could ever get the engine off let alone the rest. 

Still looking for a reputable person/business to do the work. I would love any recommendation.

I had someone suggest the boat Docktor in Apple Valley. Anyone heard of or had any work done by him?

Also, please feel free to PM me if you want.


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## Gottagofishn (Nov 18, 2009)

I talked with Lund today and they suggested drilling out the hole to completely eliminate the corrosion and use a bolt to seal it. All of this assuming the transom is not rotten. If I would do this what kind of bolt should I use? I read somewhere that other metals will react with aluminum?


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## M.Magis (Apr 5, 2004)

Use stainless steel.


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## crappiedude (Mar 12, 2006)

Gottagofishn said:


> I read somewhere that *other metals will react with aluminum*?


Yes, that is true. However, if you seperate the different metals with a nylon or rubber washer you should be fine. Just be sure to seal the bolt with a good *marine caulk* like the 3m brand.


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## Gottagofishn (Nov 18, 2009)

Thanks for the info, I will repair this weekend. 
If you see me swimming around in the middle of alum or Erie with a fishing rod in my hand stop and pick me up. Hit a waypoint so I can go back and get the rest of my gear.
J/K...... (I hope)


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## Gottagofishn (Nov 18, 2009)

Uh....one more thing. Can anyone tell me specifically how to check for an electrical drain? I have a multimeter but no idea how to see if individual pieces of electronic equipment are grounded to the hull. I suspect it would most likely be the sonar, aerator, charging system or trolling motor.


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## crappiedude (Mar 12, 2006)

1st I'm not an electrican or even close but I do know enough to get by or at least get in trouble.

I would take the multi meter and set it on DC, like at 50v. I'd put the negative to the ground, I'd take the positive lead and poke it around on the hull and see if the meter moved.
You shouldn't get any kind of a reading at all. I would also look to see if someone ran a ground to the hull for some reason either at the battery, the fuse block or the trolling motor or just kind of look at your wiring and see if some insulation is worn.
That zinc anode being loose could have caused the problem.
What's going on there isn't normal thats for sure.
Good luck with it and keep us posted. That's weird.


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## nikmark (May 26, 2009)

I had the transom replaced on my 1998 ProV a couple years ago by Lund. Same issues you are describing. I popped out the splash well drains and the wood was all wet and soggy in there. Inspected under the transom cap too and saw enough that it concerned me. 

I did a little research and found a posting on walleye central about another guy that had the same problem. I guess the rotting wood creates a mild acid. Putting that between two metal plates creates battery-like corrosion.

I had the boat de-rigged and took it to Lund myself. They had it about 6 weeks and replaced the complete transom, including the outer aluminum skin, and repainted to match. Lund charged me about $2,500 since I wasn't the original owner.


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## Gottagofishn (Nov 18, 2009)

Thanks for that info. So far they act like they won't do anything to help.


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## nikmark (May 26, 2009)

Gottagofishn,
I sent you a PM, but not sure if it went through. I'm attaching some pictures. The thru-hull splashwell drains are just two plastic halves that friction fit together with some sealant on them. I used a flat screwdriver and worked it under the outer edge. May need a hammer to lightly to tap it in and get started. Just work your way around the edge a little at a time and keep working it apart. It only took me a couple minutes per side.


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## Legend killer (Apr 20, 2011)

nikmark said:


> I had the transom replaced on my 1998 ProV a couple years ago by Lund. Same issues you are describing. I popped out the splash well drains and the wood was all wet and soggy in there. Inspected under the transom cap too and saw enough that it concerned me.
> 
> I did a little research and found a posting on walleye central about another guy that had the same problem. I guess the rotting wood creates a mild acid. Putting that between two metal plates creates battery-like corrosion.
> 
> I had the boat de-rigged and took it to Lund myself. They had it about 6 weeks and replaced the complete transom, including the outer aluminum skin, and repainted to match. Lund charged me about $2,500 since I wasn't the original owner.


Shouldn't this be a warranty problem?


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