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White Rust oxidation at waterline

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BucketsII

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I live in key largo and put my pontoon in water for the summer months, store in winter. This is 3rd summer in saltwater. I painted with antifoul paint when purchased and had to repaint beginning 2020 summer. When I pulled pontoon out a couple weeks ago I found that there is white rust at waterline and a couple of patches where paint fell off because rust underneath paint. Please see pictures. I would like to know what I need to do before I put her back next summer and what I neglected to do to prevent this. Thank you20201126_173634.jpg20201126_173704.jpg20201126_173740.jpg20201126_173647.jpg
 
Yikes! Sorry to see that but hopefully some of our saltwater friends can weigh-in on the issue. Please don't take offense, but never in my wildest dreams would I have thought that Key Largo had a boating season. Call me envious of your neighborhood... :)
 
BucketsII said:
I live in key largo and put my pontoon in water for the summer months, store in winter. This is 3rd summer in saltwater. I painted with antifoul paint when purchased and had to repaint beginning 2020 summer. When I pulled pontoon out a couple weeks ago I found that there is white rust at waterline and a couple of patches where paint fell off because rust underneath paint. Please see pictures. I would like to know what I need to do before I put her back next summer and what I neglected to do to prevent this. Thank youView attachment 28383View attachment 28384View attachment 28385View attachment 28386
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I think that's a good enough excuse to buy a new Bennington (Ha) !
 
Michiman said:
Yikes! Sorry to see that but hopefully some of our saltwater friends can weigh-in on the issue. Please don't take offense, but never in my wildest dreams would I have thought that Key Largo had a boating season. Call me envious of your neighborhood... :)
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Lol, lived here for 60 years and too much of a good thing makes you not appreciate it. I make myself take a break and do something else during winter months. End up fixing stuff at home that gets neglected during summer and take motorhome out. Except I head north instead.
 
Just by chance, and dumb question, but you did use proper anti foul paint, correct? Copper free? Also, proper (or good condition) salt water anodes?
 
I’m in salt water but mine is kept on a lift so I’m not having this issue. Sorry and good luck getting it figured out.
 
SEMPERFI8387 said:
Just by chance, and dumb question, but you did use proper anti foul paint, correct? Copper free? Also, proper (or good condition) salt water anodes?
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The company that painted it the first and last time is used to painting pontoons and swears they use the correct paint. I religiously replace the anodes.
 
My guess is, just like any other “paint” there must have been cracks/scratches that allowed water to intrude behind the paint, and just like a metal car, you start to have corrosion. As how to fix that, I’m not sure with an aluminum toon, but I’m guessing, just like an auto, you have to remove/neutralize the corrosion, along with the portions of paint with corrosion underneath. If your company is knowledgeable on painting toons, they might be able (or recommend) a repair. This can’t be the first time they’ve seen something like this.

If the damage ends up getting too severe, possibly in the future, there was a thread awhile back where a members toons pitted beyond repair. If I remember correctly, they were going to overlay them with a skin of new aluminum. Not cheap, but probably a lot cheaper than a couple new toons shipped and installed.
 
Wow! That sure looks like something galvanic. How do the anodes look after a season? Is it correct to assume that this year is significantly different from previous years? You may need someone that is really good at finding electrical leakage potentially from your boat, the dock or immediate area (could even be a problem with the electrical service to a house or area). Have you considered active galvanic control?

Could be there is nothing wrong with the paint, except that any boundary (including scratches) focuses the discharge. In any event, I wouldn't do any swimming in the area until you know.
 
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Yes, totally different this year. The initial paint was done February 2018 and lasted me 2 summers with no ill effects. I had it repainted on June 18th 2020, just 5 months ago and this is how it looks now. Same local company did both paint jobs. I also put new anodes in June. What is active galvanic control?
 
There are a number of systems. The link below is just one NOT intended for an aluminum boat...but there are others. However before going that route, my speculation from afar is that there could be more than one problem (with, maybe, only one of them on your pontoon). More investigation/fact-finding is in order. Do you dock in a marina? Are other boats in the area showing any damage. Might there have been quickie or incorrectly done repairs after the storm damage that effected your whole area? Damage to some electrical cable could be completely unintentional and very hard to see/find.

I can't tell for sure if the general appearance of your logs is due to condensed salt or more galvanic damage to bare metal above the water line. If the ladder, that is huge (relatively speaking) discharge (meaning any electron or ion involvement in any direction). In that case, even if you find a problem on your boat, what happened is bad enough that there could be something more to find. Again just speculation from afar, but if this happened in a marina, contact the marina owner sooner rather than later. Not to be overly dramatic, but you literally could save a life... In any event some local professional help in in order.


In an attempt to lighten the issue, your pontoon does not glow in the dark, right?
 
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Lol, not glowing in the dark-yet! Ok, looks like i have to do some investigation.
 
Went to look at pontoon today and was able to find the 3 toons with the same amount of corrosion. The outside toons had intact anodes but the engine mount and engine anodes were really bad. All were installed in June 2020. Marina where I leave it has no shore power but I did have it at a friend canal in bay for a couple of weeks during an ocean storm. His canal is full of motorized boat lifts. Can electrolisis galvanization happen in such short time? See pics
 

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The short answer is yes. Such discharge has completely destroyed outdrives and even welded internal parts (gears) in a surprisingly short time. Use caution in trying to id the source of the problem. Any number of things could happen during storms/high water that aren't apparent today. Heavier damage dockside is a good tip, but not enough to call the whole story. Certainly the canal storage is suspect, but I wouldn't rule out your marina even if there is no shore power.

I suggest you call your insurance company. This could be accepted as storm-related damage. See if they will pay for and suggest someone to do a survey on your pontoon (focus on the electrical system for damage, repairs or modifications...any of those should be suspect). If they won't, I'd suggest you do that on your own.

AND BY ALL MEANS don't let anyone in the water near either dock or your boat until you know more! What you have isn't just galvanic, this is power leakage of some kind.

BTW: Good work, don't stop.
 
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Thank you for the pointers. We did have several king tides during the summer as well as storm surges. Water could have reached some electrical connections.
 
Here is the impacts of king tides at our place.
 

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I read this article after Dan had posted it in the other thread. Super informative and educational on the topic of marine corrosion.
 
Thank you.
Just as a follow up to my thread, I contacted Bennington and they recommended to clean the pontoons, seal them and then apply anit-foul paint to the complete pontoon and not stop at the waterline. I think it will look ugly but I rather have an ugly boat then a rusted one. LOL
 
BucketsII said:
Thank you.
Just as a follow up to my thread, I contacted Bennington and they recommended to clean the pontoons, seal them and then apply anit-foul paint to the complete pontoon and not stop at the waterline. I think it will look ugly but I rather have an ugly boat then a rusted one. LOL
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Might be an idea for saltwater blackout owners.
I’m thinking I may get my toons wrapped “down” to the waterline before spring splash depending on the cost.
 
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