Bottom Paint Blisters near metal

[jfelds]

Hi All:


We just hauled out and found an interesting issue. Almost everywhere I have metal below the waterline I am losing paint. In many spots it is down to the glass, having gone through the paint and primer.


However, none of the metal is wearing or pitted, or is pink which leads me to believe the bonding is ok? Why is this happening and how do I fix it before I cover it up with bottom paint? Thanks.


Jim
MV Kokomo

 

[IntervaleII]

Hi Jim, how’s it going?
It could be electrolysis from a neighbors boat if it isn’t yours.
I had a similar issue with our 48, I determined it was from a neighbors boat. Was it like this during your last haul out.

 

[jfelds]

Hi Don:


Thanks for the quick reply. It was NOT like this during last haul out which was last November at your marina in Chesapeake, or at least no one including me and the crew noticed it.


I'm going to put the positive from a meter on one of the thru hulls and and negative into the rocks and see if I can get a reading. If I don't get one, then it is likely a neighbors boat. Hope all is well. Thanks.


Best,


Jim
MV Kokomo

 

[bayview]

yes probably stray current. can be hard to locate the cause.

 

[psneeld]

Don't panic, blistering or "burning" of paint has sometimes been associated with zincs....

If I recall, too much zinc may be an issue or it can be a zinc vs paint issue...not all that uncommon.

 

[tiltrider1]

Don't panic, blistering or "burning" of paint has sometimes been associated with zincs....

If I recall, too much zinc may be an issue or it can be a zinc vs paint issue...not all that uncommon.

Very common If you use a heavy copper bottom paint like Petit Trinidad and have unregulated zinc anodes.

 

[kchace]

Blisters around a through hull can certainly be caused by too much zinc, but it can also be caused by stray current. Even if the odds are low, the seriousness of stray current means you should find out the cause ASAP.


Check out this article from Passage Maker.


https://www.passagemaker.com/technical/-through-hull-fittings-and-canaries-in-coal-mines




Ken

 

[foggysail]

Hi All:


We just hauled out and found an interesting issue. Almost everywhere I have metal below the waterline I am losing paint. In many spots it is down to the glass, having gone through the paint and primer.


However, none of the metal is wearing or pitted, or is pink which leads me to believe the bonding is ok? Why is this happening and how do I fix it before I cover it up with bottom paint? Thanks.


Jim
MV Kokomo

Is the paint loss only around through hulls? If so, are the through hulls bonded assuming they are bronze?