"Melting" Bottom Paint???

Hello all -



Hoping your combined years of experience can shed some light on a puzzlement for me...



For years, I have used self-polishing Jotun anti-fouling paint on my boat and it has performed just fine in the Baltic, Öresund and North Sea areas (Salt & Brackish water). Last year, I cruised from Sweden to the Mediterranean, which entailed a few months in Fresh water rivers and canals. A few weeks after arriving in the Mediterranean, I took a stiff brush with me while swimming one day in order to clean "canal scum" off the bottom paint around the water line. Scum came off easily and everything with the paint seemed normal and as expected.


Not long after, I was in the Port of Barcelona for about a week. During one day of my stay there I noticed that the normally clean water at my marina was brown and a bit foamy. The next day, the water looked normal again, but a lot of gunk had stuck to my boat around the waterline. So, I set about brushing off the mess. After a few minutes of my usual brushing maneuvers, I noticed that I was literally painting grey bottom paint onto the adjoining white part of the fiberglass hull with my brush. I looked at the brush and it was totally covered with the gooey gray anti-fouling paint. Only then did I try feeling the bottom paint on the hull, discovering that it was very soft - like it had just been painted.


I spent the next couple of hours cleaning the paint mess off the white part of the hull. Had to throw the brush away.


I had my home boat yard in Sweden contact Jotun, the bottom paint manufacturer, and they had no explanation. They had never heard of anything like this.


A month later, the boat was hauled out of the water for the winter and the paint was STILL quite soft, though not as soft as when I first noticed the issue.


I wonder if there was some type of oil or checmical spill in Barcelona harbor while I was there, causing the brown/foamy water for for a day. And, if it was an oil spill, do any of you know if what I experienced with my bottom paint is something normally caused by the presence of oil in the water?


Perhaps you might have some other thoughts on what might soften anti-fouling paint?



Thank you, in advance for your ideas!

No idea what might have caused the problem but you will probably need to completely remove all the old paint before repainting the bottom with new paint. Maybe talk the paint manufacturer to kick in the new paint at least. I like soda blasting to remove the old bottom paint. Good luck.

Scott, I’m unable to shed any light on your dilemma although I would not have been at all surprised if you had told me that had happened in a French canal, but I’m fascinated by that trip. Did you write about it? If you did, is it on here?

Thank you Comodave for your response. I totally agree that the paint will need to be removed. Thank you, also, for the soda blasting tip. Talking to the manufacturer again is not out of the question, but I am a bit reluctant to believe it could be any kind of manufacturing quality issue with the paint. I've used this very same paint for years in both fresh and salt water. Never any problem before.

Just because you have had good luck with it in the past doesn’t mean that you may have gotten a bad gallon or two. I would ask them to replace it under warranty and they may just do it for good customer relations. If they don’t you really have not lost much except a bit of time. If they do you will save several hundreds or more. Why not try? What does a couple gallons of paint cost the manufacturer? And if they replace it you will be telling everyone how responsive they were. Good customer relations.

Hello Xsbank.



You make a good point about canal water. It can be depressingly "dirty" at times. On the bright side, despite challenges with weeds here & there, I never had to go swimming in it



Regarding your question about our trip...
No, I did not write about it here, or anywhere. Have thought about it a bit, because it was a very interesting trip. We took a few thousand pictures. I put up three of them in the Pictures/Albums section of this Forum yesterday.



I wrote earlier that a few weeks after arriving in the Mediterranean, I went swimming and brushed off the canal scum from around the waterline...and that the paint was entirely normal then. The reason I mentioned this is that, in my mind, it ruled out anything prior to that swim as the cause. Perhaps I shouldn't have been so quick to jump to that conclusion. As you imply, canal water can be pretty bad. Perhaps what I experienced in Barcelona was just the culmination of a slow breakdown process that started all the way back in the canal part of our journey. And, reflecting a bit further, if canal water were the culprit, my guess would be that the problem originated in Belgium, not France. There is an unbelievable amount of industry along the canals in Belgium.


Many people traverse canals in this part of Europe in rental boats. Most are fairly local 1-2 week rentals, with only a valid driver's license (from anywhere) required. Others charter boats on a longer term basis (often from the Netherlands). And then there are those who buy boats (again, often in the Netherlands) and use them for several years to explore the inland European waterways and then sell them again. We met a fair number of people from the US and Canada doing this on our trip. Non-EU citizens having journeys lasting longer than 90 days, however, have to leave the EU and come back "later" to continue. There are apparently quite a few "strategies" for accomplishing this.


Do you think it would be something of interest to enough forum members for me to summarize my journey, along with some pictures, on a new thread about this?


Best regards,


ScottC

Thanks, Comodave, you make a very good point!

Industrial waste discharge?

Scrape off a sample and send it to the manufacturer for analysis?

Something with solvent properties came down the sewer, and you’ll probably never know exactly what.
The damage to the bottom paint is likely just near the waterline, hopefully does not extend to deeper parts of the bottom.

jleonard said:

Scrape off a sample and send it to the manufacturer for analysis?

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ScottC said:

Thanks, Comodave, you make a very good point!

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Dave and Jay both have good suggestions.
You might ask the mfg if they would do some lab analysis to see if they can identify a chemical contaminant or solvent that could have caused this. I'll bet they have a sophisticated lab and equipment that might provide info. I wouldn't be too pushy with replacement but you could leave that to them based on their findings. If they agree, They will likely be looking for any variances in their normal formulation. They will likely not admit much detail if they find any error on their part but will be more likely to replace the paint.
Not much to lose other than some time and postage.

In the marina where I dock, they were construction 2 more high rise condos. Plastic lunch bags would blow off the floors and when they would pour concrete, some would blow off the site onto cars and sometimes a boat or two. The construction company ended up washing more than a few cars and boats.

We had a 150 gallon gas fuel spill a while back in our marina about 5 slips down. It affected the bottom paint at the water line on my boat, port side and about 1/2 way across the stern. I had to removed everything down to the glass as it was bubbling and melting. Might be something of the same sort? Hard to tell.

Thank you, everyone, for all of your good ideas and suggestions! I especially like the suggestion of sending a scraping sample to the manufacturer.

RonR said:

We had a 150 gallon gas fuel spill a while back in our marina about 5 slips down. It affected the bottom paint at the water line on my boat, port side and about 1/2 way across the stern. I had to removed everything down to the glass as it was bubbling and melting. Might be something of the same sort? Hard to tell.

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Hi RonR - what you describe sounds very much like what I experienced. The problem was mainly at the waterline...and there was bubbling.

It’s a good idea to work with the manufacturers to try and determine what happened to the paint, as that may be helpful to their R&D for future products, as our waters become increasingly polluted.
However, I don’t think it’s a great idea to go after them for freebies, as in all likelihood, it’s no fault of theirs.
Nobody needs bad karma, especially cruisers!

kapnd said:

It’s a good idea to work with the manufacturers to try and determine what happened to the paint, as that may be helpful to their R&D for future products, as our waters become increasingly polluted.
However, I don’t think it’s a great idea to go after them for freebies, as in all likelihood, it’s no fault of theirs.
Nobody needs bad karma, especially cruisers!

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They may want a ‘wet’ sample so get an air tight container for your scrapings.

jleonard said:

Scrape off a sample and send it to the manufacturer for analysis?

Click to expand...

Agreed.

Do you apply the bottom paint or get someone else to do it for you? If you do then could those applying the paint have stretched it out with thinners or other solvents? Might have not noticed it in cold water but may have softened in the warmer waters of the Med??

I would imagine that most in North America have little experience with Jotun paint.
A friend of mine used it once on his sailboat. He told me it was very thick and required some thinning to roll on.
Don't know how that could affect the warm to cold water situation??
It worked OK for my friend, but he had a consistent environment.

Hi Ralsy & Firehoser75,
I have used this Jotun paint for 9 years. It has been applied by the same painter at the same boat yard for 9 years. Don't know whether they thin it or not, but this is the first year I've had any problem. This doesn't entirely rule out some change in application procedure that I'm unaware of, however. Thank you for your thoughts.