Keel/Bottom
Posted: Fri Jun 04, 2021 8:41 pm
In 2019 I had my marina sand and paint bottom with Micron WA. All previous years I use Micron CSC. I stay in water at least 3 years and use diver on non hauled years to clean bottom. Boat stays in water all winter and I hang a 2 in x 8 in zinc over side connected to bonding system of boat. When I came back to boat in spring of 2020 the zinc was completely gone. In July of 2020 when diver cleaned bottom he noticed a large areas on side of keel and around a few thru hulls that had what he called looked liked watermarks with large accumulation of barnacles. When marina hauled this week they noticed the following from pictures below. They immediately thought I had a bonding issue. One of my thru hulls is not bonded and had none of the effects as noted in pictures. Every thing that was bonded is shown in pictures. I checked the connection from outside the hull between each of the affected thruhulls, the strut, a bare spot of lead on bottom of keel, and between three of the exposed keel bolts to the bonded keel bolt in the bilge. All read within a few tenths of an Ohm.
Checked from the male end of the power cord from the ground pin to a thruhull and that read open with the normal diode and capacitive action of the galvanic isolator. Ground to Neutral and Hot pins of the male end of power cord were isolated just as they should be. The shaft was isolated from the bonding system since it connected thru transmission and that is not a good electrical connection to engine.
In the past when I did my own bottom I always coated any bare spots on keel and any exposed metal on thruhulls and strut with epoxy primer Interlux 2000E or similar. I asked marina to do the same and bill me for the primer. Boat was sanded one day and bottom paint applied the next. I never received a bill for the epoxy primer paint. What are your thought and what affect would be realized if one applied copper based paint directly to lead keel or bronze substrate?
Ok to jump to a conclusion my thoughts are galvanic corrosion and not elelctrolysis. Thanks to the 2in x 8in zinc that was hanging off side connected to the bonding system of boat it protected the lead keel and thru hulls. I am confident that the problem was a result of copper paint on lead keel substrate with lack of primer. The marina keeps pointing to bonding issue which I already confirmed was ok. Now the latest today was there paint guru (I think that is what he was) looked at the paint chips I pulled off the keel with a putty knife and claimed there was filler between the keel and the grey/light colerd epoxy coating (I believe what he was referring to was Interprotect 2000). I believe Freedom used epoxy sim to west sytem to fair lead keel to bilge stub. The person grinding keel today was having a tough time grinding it down to bare lead and refered to it as a dark green or grey colored material. She thought is was applied by the manfacturer which I agreed. I was able prior to marina attacking the grinding was to with a couple of putty knives force off a good percentage of the epoxy coating to which now there is only about 75% that is left to grind off. FYI I contacted Interlux and they agree one shoud never apply copper bottom paint to bare lead.
I also used a silver cell over side and checked levels to each of the bonded parts (thruhulls and keel). All were within the protected levels for their corresponding metals.
I firmly believe marina is trying to cover their butts. Which I completly understand but they are not dealing with your typical know nothing boater. I've been doing this for over 40 years and 20 years with this boat .I know my boat. I stripped her down in 2001 and rebuilt her.
Checked from the male end of the power cord from the ground pin to a thruhull and that read open with the normal diode and capacitive action of the galvanic isolator. Ground to Neutral and Hot pins of the male end of power cord were isolated just as they should be. The shaft was isolated from the bonding system since it connected thru transmission and that is not a good electrical connection to engine.
In the past when I did my own bottom I always coated any bare spots on keel and any exposed metal on thruhulls and strut with epoxy primer Interlux 2000E or similar. I asked marina to do the same and bill me for the primer. Boat was sanded one day and bottom paint applied the next. I never received a bill for the epoxy primer paint. What are your thought and what affect would be realized if one applied copper based paint directly to lead keel or bronze substrate?
Ok to jump to a conclusion my thoughts are galvanic corrosion and not elelctrolysis. Thanks to the 2in x 8in zinc that was hanging off side connected to the bonding system of boat it protected the lead keel and thru hulls. I am confident that the problem was a result of copper paint on lead keel substrate with lack of primer. The marina keeps pointing to bonding issue which I already confirmed was ok. Now the latest today was there paint guru (I think that is what he was) looked at the paint chips I pulled off the keel with a putty knife and claimed there was filler between the keel and the grey/light colerd epoxy coating (I believe what he was referring to was Interprotect 2000). I believe Freedom used epoxy sim to west sytem to fair lead keel to bilge stub. The person grinding keel today was having a tough time grinding it down to bare lead and refered to it as a dark green or grey colored material. She thought is was applied by the manfacturer which I agreed. I was able prior to marina attacking the grinding was to with a couple of putty knives force off a good percentage of the epoxy coating to which now there is only about 75% that is left to grind off. FYI I contacted Interlux and they agree one shoud never apply copper bottom paint to bare lead.
I also used a silver cell over side and checked levels to each of the bonded parts (thruhulls and keel). All were within the protected levels for their corresponding metals.
I firmly believe marina is trying to cover their butts. Which I completly understand but they are not dealing with your typical know nothing boater. I've been doing this for over 40 years and 20 years with this boat .I know my boat. I stripped her down in 2001 and rebuilt her.