Corrosion help

I have a 04 Alumacraft Navigator 175 that I bought new. We have taken excellent care of the boat which these last 3 years having seen very little use. I was cleaning it up the other day and noticed on the transom two spots of corrosion about the size of a .50 piece, one on each side of the motor about by the waterline.

Any ideas on what I should do to fix the two spots before they get worse? At this point the paint is basically bubbled but over time it will just get worse. I didn’t know if this was an easy fix or something I should try and have a pro do. With that said any shop recommendations in the north metro?

Thanks for any replies, tips, or comments.

WS

The way I repair such areas is start with an 80 grit paper. Sand back the area until all the oxidation is gone all small pits are sanded out with the 80 grit. A dime size paint bubble might be 3 inches by the time it is sanded out. I will use a 220 grit to smooth and finish feathering out the 80 sanding marks. I use PPG DZ503 aluminum primer it is the best I have found for aluminum. Follow directions and once applied and dry it is ready to paint.

Thank You Sir! For a bit there I thought I was the only one to have a problem like this. I will follow your instructions.

Thanks again!

WS

Old thread but I found a similar issue w my boat. 2007 alumacraft 185 t.p. tiller. Going to check electrical and dig into it further today. I’m not sure if it’s electrolysis or a reaction between the treated lumber and the aluminum. Just wondering if there’s any other people on here that have dealt with a similar issue.

Thanks-Pete

Attachments:

1. 

   Screenshot_20240516-110358.png
   

2. 

   Screenshot_20240516-110402.png
   

This looks like one of the first signs of transom rot on the Lunds.

Ok. I’m going to pull a screw from the top cap and see how soft the wood is.

Thanks for posting this I just notice this on my 2006 Alumacraft also.

Transom rot

bigcrappie wrote:

Transom rot

Yes and you wont realize how bad they are unitl you remove the wood. I’ve seen some that I can’t believe the motor was still hanging on.

Attachments:

1. 

   Compress_20240516_152157_7527.jpg
   

There’s current running through the hull also! Time to bring it in and have someone who knows what they’re doing look at it

Bummer

Attachments:

1. 

   Screenshot_20240516-164525.png
   

2. 

   Screenshot_20240516-164541.png
   

It’ll get bad enough you can push your finger through it. My friend’s boat got that bad and needed the transom replaced. $$ Kinda like a Silverado tranny rebuild.
When I traded in my 21 year old Lund it was just starting to show it. Dealer knocked off $2000 on the trade in. I think my friend’s boat was much worse because he backtrolled while I used a bow mount trolling motor. A lot more water getting inside his transom.

This definitely can be sign of a rotting transom, but the fact that the corrosion is at or near the water line can point towards the hull carrying voltage like PMB said. Rotten transom paint bubbling will normally start at screws in my experience.

Mike Synicyn wrote:

Thanks for posting this I just notice this on my 2006 Alumacraft also.

Dont scare me like that. This is the year of my Alumacraft.

CaptainMusky wrote:

Dont scare me like that. This is the year of my Alumacraft.

Phew! I just checked mine and it looks fine, but my boat has not seen much use the last several years and it always indoors not sure if that matters.

Bringing it to Dan’s where it was originally purchased on Monday to get it diagnosed / quote for repair. Will post what they tell me. Probably will go elsewhere for actual repair. Unfortunately it’s probably the electrical I did or the transducer plate I mounted. Depending on what they say I’m tempted to patch the holes and at least be able to fish local/ smaller lakes. No noticeable flex in transom

I just noticed all the notifications for this topic.

I am the original poster seeking help with my corrosion problem on my 04 Alumacraft Navigator 175. I lost a few nights sleep over the deal, then I called Alumacraft in St. Peter and talked to them.

They were wondering if I had an onboard battery charger, which I said I did. They said improper installation could be the cause, but at any rate they would need to inspect it and I would have to leave it for 2-3 months so they could decide course of action. I told them that once they figured it out, I wanted to have a quote before they fixed anything which they said they would do.

The boat sat down there for about 4 months. One day I got a call and they said it was ready for pickup. I asked what they ended up doing and they said they replaced the entire transom. I had a sick feeling in the pit of my stomach when I asked what the bill was? They said that Alumacraft had a 1x fix on any product defects or faulty workmanship, and mine fell into these categories.

They never said exactly what caused the corrosion, but in the end materials and labor were covered by Alumacraft and my cost was $0.00.

WS

When mounting onboard chargers it’s recommended to put a non-conductive material between the charger and the boat. My dealer used a transducer mounting board.

supercat wrote:

<div class=”d4p-bbt-quote-title”>bigcrappie wrote:</div>
Transom rot

Yes and you wont realize how bad they are unitl you remove the wood. I’ve seen some that I can’t believe the motor was still hanging on.

It looks like it was plywood that was never sealed and it goes all the way to the floor where it sits in water? No?

Lots of guys with transom rot but anyone ever see someone’s transom flex and cause issues ? My buddy’s theory was run it till the motor falls off ha.

WOW!!! scary