I have a Pacific Seacraft 40.
Starting in 2007 the Interprotect barrier coat has chipped off at several isolated locations on the sides of the lead keel.
Twice during the subsequent years the chipped areas have been ground down to the lead and then re-coated with 4 layers of Interprotect barrier coat. Nevertheless the re-coated spots fail again after approximately a year.
It is always the same locations and fortunately not a problem on the surface of the rest of the keel
It has been suggested to me that maybe this is (or was) caused by electrolysis. While using a Corrosion Reference Electrode to check for electrolysis it was noted that when the associated digital multimeter was connected to the rigging and mast step that the readings were significantly different than when connected to the battery negative or engine. However both readings were in the correct range of -750 t0 -1000mV indicating that there is satisfactory cathodic protection.
The PS owners' manual states that the rig is connected to a keel bolt for lightning protection. Does this imply that there is not a common ground to which everything is connected? If so, is this o.k.?
Any thoughts you have on this issue would be appreciated.
Bob
Starting in 2007 the Interprotect barrier coat has chipped off at several isolated locations on the sides of the lead keel.
Twice during the subsequent years the chipped areas have been ground down to the lead and then re-coated with 4 layers of Interprotect barrier coat. Nevertheless the re-coated spots fail again after approximately a year.
It is always the same locations and fortunately not a problem on the surface of the rest of the keel
It has been suggested to me that maybe this is (or was) caused by electrolysis. While using a Corrosion Reference Electrode to check for electrolysis it was noted that when the associated digital multimeter was connected to the rigging and mast step that the readings were significantly different than when connected to the battery negative or engine. However both readings were in the correct range of -750 t0 -1000mV indicating that there is satisfactory cathodic protection.
The PS owners' manual states that the rig is connected to a keel bolt for lightning protection. Does this imply that there is not a common ground to which everything is connected? If so, is this o.k.?
Any thoughts you have on this issue would be appreciated.
Bob