where to mount zinc on keel?

May 23, 2016
1,024
Catalina 22 #12502 BSC
where have you guys mounted a zinc on your keel, need to do it with the keel up on the trailer, forward, aft, top, bottom? recommendations?
 
May 23, 2016
1,024
Catalina 22 #12502 BSC
dave....what would you suggest...brackish salt water, in slip year round....
 
Jun 8, 2004
10,024
-na -NA Anywhere USA
That question was asked at Annapolis by a Cat 22 owner to Frank Butler. His response was HELL NO> The way I look at this is electrolysis. First this is not a larger boat with shore power although some do have it nor does it have a gen set and all the other goodies found on bigger boats. If you have an outboard motor, they gernerally have a place on the motor for one. Generally this is an issue commonly found at the marinas with current in the water due to one thing or another like those fools who allow a shore power chord with some being worn/cut etc. allowing current into the water setting up a dangerous situation, faulty shore power on the dock or boat or what ever.
I suggested over the years to find that source. I would throw sacrificial zincs tied off to the boat overboard and see what is going on. If nothing, I would not worry but if there is an issue that zinc will tell you. Then I would start investigating looking at the shore power chords, check the shore power, meter the water etc. till you find that source. A friend of mine years ago whose son was electrocuted on a new dock at a marina, the electrician screwed up which is why one county took action. The electrician who did not have insurance lost everything.
I have heard of many things but finding the source of the electrolysis is the key my friend.
 
May 23, 2016
1,024
Catalina 22 #12502 BSC
hmmmm, interesting, gonna ask fellows at the club as to their approach too, zinc over the side is good idea...we do have 200 full slips, all with shore power, so likely leakers around...
 
Feb 26, 2011
1,428
Achilles SD-130 Alameda, CA
To provide any useful protection to a large piece of metal like your boat's keel, an anode would also have to be very large. Or there would have to be many smaller anodes.
 
Sep 14, 2014
1,251
Catalina 22 Pensacola, Florida
If you are gonna do it, put it near the dissimilar metal complex of the keel hanger and make sure you electrically connect it with the keel metal by tapping threads through your barrier material into the metal. Like so
D anode attachement and new numbers.JPG
 
Sep 14, 2014
1,251
Catalina 22 Pensacola, Florida
And yes I know the keel hangers are mounted upside down, previous owner, will fix on next haul-out.
 
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Apr 22, 2016
161
Catalina 22 Folsom Lake
Detailed explanation of galvanic corrosion and graph of various anode metals with electrical potentials in this video. Great pic @Jacktar!
So, just to check my understanding - owners that have refurbished and encapsulated keels, like @pclarksurf and others, have both added the external barrier AND the stainless insert between the keel and pin, is that correct and do those steps eliminate the need for a zinc or aluminum anode?
 
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Sep 14, 2014
1,251
Catalina 22 Pensacola, Florida
Thanks part of the series i took when going through getting it transitioned from a trailer queen of previous owner to in slip go at moments notice boat.
 
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