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Question:

Hello all, was curious to know what type of fouling paint to use for my thru hulls and running gear on my boat. I’m most interested in preventing I use the same paint that I use on the fibreglass bottom. If I remember correctly one is not supposed to do that because copper fouling paint on bonded hardware promotes electrolysis?? Thanks in advance

Response:

The aggressiveness of galvanic corrosion between dissimilar metals (copper in the paint and the thru-hull metal) is primarily a function of the difference in their corrosion potentials (Galvanic Series of Metals in Seawater Tables). Copper’s corrosion potential ranges from 300 to 570 mV, silicon bronze from 260 to 290 mV.  A difference of 40 mV in the first case and 280 mV in the second case.  Differences in corrosion potentials of less than about 200 mV are relatively insignificant.   The thru-hulls on my 30 year old boat, which had always been painted with copper-based bottom paint, showed no visible effect of corrosion.  In short, I wouldn’t worry about it. Regards, Ev – Hide quoted text — Show quoted text – Hello all, was curious to know what type of fouling paint to use for my thru hulls and running gear on my boat. I’m most interested in preventing I use the same paint that I use on the fibreglass bottom. If I remember correctly one is not supposed to do that because copper fouling paint on bonded hardware promotes electrolysis?? Thanks in advance

Response: