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Re: Zincs- More is better?
Posted: Thu Jun 13, 2019 6:48 am
by Fastjeff
If your CAPAC reading is too high (1.2 up) then there's too much protection.
Jeff
Re: Zincs- More is better?
Posted: Thu May 06, 2021 9:19 pm
by Studini
barkleydave wrote: ↑Sun May 12, 2019 11:47 am
There is still confusion regarding galvanic protection. I have used a mag. hang over anode for 15 years now to bring my numbers up. I have the correct anodes on my 29 provided by BoatZincs.com. While the numbers increase they still fell short of the recommended -.95- -105 . mv By using the mag anode it brings my number up to the correct range. What some may be confusing is the continuity factor as mentioned in an earlier post. Just hanging an anode for the side on a FG boat it pointless. It must have continuity. Now our Big M's do just that. By attaching the cable to a stanchion for example the stanchion is bolted directly to the aluminum deck and completes the circuit. If I remove anode the numbers drop immediately!
I hang mine over the side on the stern directly over the location of struts, rudders and props. I have NO evidence of galvanic corrosion anywhere on my Big M. I pulled the boat late last summer for a complete bottom strip and repaint and everything was absolutely perfect. (We did find where a strut bearing had come loose and almost backed completely out of the strut! (caught that in time!)
When we pull the boat (every 4th season) we remove the bar anodes clean and re-install or replace as required. Even with clean anodes making complete contact with the hull numbers improve but only for a short time.
Now you can expect your numbers to run slightly lower in fresh water. (the cleaner the water the less continuity)
Clean your over the side anode at least once a month and use ONLY a stainless steel brush! My anode is full of deep pits which shows it is working and has been for at least the past 9 years and still has plenty of life left.
In summary; by connecting a mag (fresh water only !) to a stanchion protection is thereby provided. " A hanging anode can provide protection if it is connected by a wire to the metal being protected."
I know this is an older post.. hope someone is still watching.. Question: isn’t our stanchion isolated with a rubber gasket to the hull?
Re: Zincs- More is better?
Posted: Fri May 07, 2021 6:32 am
by Bryank97
Although the stanchion is isolated with a rubber gasket, the stainless screws are screwed directly into the aluminum, which is making the electrical connection. Really it all comes down to what your hull potential reading is on the CAPAC. Ideally you would have enough "zincs" which really should be magnesium in freshwater applications, that you do not have to add a guppy hanging over, because then you have to remember to pull it up before you leave the dock.
Re: Zincs- More is better?
Posted: Fri May 07, 2021 3:28 pm
by Fastjeff
I regularly clipped the lead from my "guppy" to the railing and it worked fine.
Jeff
Re: Zincs- More is better?
Posted: Sat May 08, 2021 8:55 pm
by GB49
The stainless bow rail screws to the Aluiminum are only an issue if you have a medium other than air. In most cases the rail brackets fill up with gunk, the weep holes get clogged by the gunk and also partly by the rubber gasket pushing into the weep hole and the base begins to retain moisture. You now have stainless, water & Aluminum reacting with each other. The less noble metal will loose.
Caulk all screw holes and clean out any brackets so they can dry. Its really that easy.
Throw out the bow rail factory gaskets and use nylon washers as spacers and caulk the screws. The brackets can be cleaned out with a hose, will remain super tight and will not corrode. I did mine many years ago with zero issues.
Re: Zincs- More is better?
Posted: Sun May 09, 2021 4:25 am
by rickbo
I'm in the theory you can't over protect with the aluminum anodes. The anode produces a set voltage no matter how much you use , whether it be one foot or 20 feet. Think of it like a battery. If you have a 1.5 volt battery thats what you measure with a meter. Now take 20 of those batteries and put them in parallel and you still have 1.5 v , but they will last a lot longer .The disadvantage with less is that you will burn them off faster. If you have more it just gives you more contact area to maintain a good connection. I do believe you can over protect using magnesium since it generates 1.1 to 1.2 v
Re: Zincs- More is better?
Posted: Sun May 09, 2021 9:01 pm
by jralbert
Everything I've read indicates you CAN overprotect.
Re: Zincs- More is better?
Posted: Sun May 09, 2021 10:01 pm
by rickbo
Re: Zincs- More is better?
Posted: Tue May 11, 2021 8:51 pm
by Studini
I made my own “guppy”. So I added a 3 1/2# block of magnesium with a 12ga copper wire to a battery cable clamp. Clamp it on my stanchion which I think means my chrome railing and I added a point to my reading to get me to .9 on the nose. I’d like to get that extra .5 reading... would a bigger block of mag do it or possibly different shape with more mag exposed to the water?
Re: Zincs- More is better?
Posted: Tue May 11, 2021 10:45 pm
by rickbo
My home made one gets me to 1.2 which is a little high. I get different readings depending on where i clip it. I found that clipping it to the stanchion base is a lot better than the stanchion itself