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Installing a new shaft mounted zinc on my Oday 272LE. The boat lives on a mooring but we spend atleast four weeks at marinas. As far as the bolts my question is due rotation and vibration frequency it lives in should i use blue or red lock tight?
 

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I'd use neither.. we've never had a zinc fall off that was properly tightened. If vibration is a problem you need to realign the engine/shaft coupling to remove it..
 

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MikeGuyver
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When you install the zinc tap it several times with a hammer, they are not machined perfectly, clean the shaft off with fine emery cloth, cinch the bolts snug and then tap the zinc several times with a hammer before final tightening. Zink is malleable and will "cold flow" slightly ,tapping them will help seat it to the shaft.
There was one missing from the shaft when we had our boat surveyed, it had been installed by the yard just a few weeks earlier.
 

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Master Mariner
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You really do not need any Loctite on shaft zincs, as mentioned above. If you tighten them as tight as you can get them by hand with an allen wrench, then they should never fall off. If you have a metal boat around, and/or one with a copper bottom, your zincs could disappear pretty quickly, but falling off, just doesn't happen all that often, vibration or no.
 

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Remember you're a womble
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Make sure to paint the thinnest part of the zinc (where the bolt holes are) with nail polish or some other non-metallic paint before you fit it. That's the bit that usually wears through first and causes your zinc to fall off.
 

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Tundra Down
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At the end or our season we park the boat in a "hot" harbor for a week or two. Schedules and weather determine how long. I had had zincs disappear on one occasion when that time period exceeded 4 weeks. Would simply disconnecting the batteries have helped? Seems like it would?

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At the end or our season we park the boat in a "hot" harbor for a week or two. Schedules and weather determine how long. I had had zincs disappear on one occasion when that time period exceeded 4 weeks. Would simply disconnecting the batteries have helped? Seems like it would?
Why would you try to eliminate the source of the problem aboard your boat? I thought the problem was a "hot harbor"?
 

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Tundra Down
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Hot harbor is the problem. I was thinking it might not interact with my zincs if they were not connected to a source? Would a zinc hanging from a string be eaten in a hot harbor?
 

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Tundra Down
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We know it is "hot" My boat spends the season in Seal Harbor with very little zinc loss. When it spends a month in North East Harbor they are reduced at a much faster rate. I wouldn't dive there. No one does.

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You are making an assumption. There are many factors that can affect zinc longevity. The hot marina (while possible, in theory) is typically an exaggeration of some much more local problem, IMHO. I work in about two dozen marinas and I'd bet money that I've heard various boat owners call every one of them "hot" at one time or another. It's a catch-all term frequently used when the boat owner is experiencing rapid anode depletion but hasn't taken the time to actually run down the problem.

I could be wrong about your marina but until somebody puts a meter into the water and proves it, you're still making an assumption.
 

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The hot harbor debate always gets hot.

I was in a marina once where I ate zincs like they were skittles. My grounding plates had halos in the paint around them. The power pole on the dock shorted and almost caught fire. I found my plug melted to it (and it never tripped the breaker!)

When I asked the marina about it, they swore they tested the water for leakage every year. If they did, it only makes me wonder whether the test is very reliable. I moved marinas the following year and can almost go an entire season on one zinc. If it wasn't the marina, I can't figure out what else it could have been. Nothing changed on the boat.
 

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Tundra Down
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I will look into it here in Northeast Harbor. My observation suggests it is "HOT". It is suggested by others, too. The harbor has several commercial and municipal docks with power and is surrounded by private docks. I will ask some folks who might have technical answers and report back.

Anyone have any experience with one of these?

Corrosion Reference Electrode and User's Guide
by ABYC-Certified Corrosion Experts

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