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Hi All,

Being a new "in the water boat owner" I have no idea how long your standard ball zincs will last. I have a 1" shaft and the PO has 2 ball zincs installed. He was paying for a diver but don't know if he was hauling out once a year. Here's my question.

A diver costs $100 + cost of the zinc(s). A haul and hang (lunchtime for the workers) cost $100... and I put on the zinc. I plan to haul and pressure wash annually on the 2 years between bottom paint. In your experience will 2 zincs last an entire year? My marina is brackish.

Dave
 

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In our experience the two shaft zincs do last a year, but I think it's a highly variable thing and tied to your specific boat/location/neighbour(s)/marina. Once you've got a season under your belt you'll have an idea..

We change them annually regardless.

btw.. if you have a mechanic's mirror on a stick and clear water it's surprisingly easy to get a decent look at the shaft zincs- at least to get the idea that they're still there.
 

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If your boat is in brackish water you should be using aluminum indium anodes, not zinc.
I'd never heard of aluminum indium anodes before. Couldn't find any definitive information but some of the blogs indicated that zinc anodes were old tech and that the aluminum indium was good in both fresh and saltwater.

One blogger commented that the indium prevents the build up of an oxide layer on the anode and the aluminum indium is more environmentally friendly than just zinc. Allegedly the aluminum indium anodes are also 5% zinc.

Anyone have any good links with references for these anodes?

Back to zincs in saltwater. I have a large zinc attached to the side of my fiberglass hull with two bolts that hold it on that go through the hull. Wires run from the bolts and attach to the engine and a contact on the propeller shaft. The zinc must be at least 5"x8" and was 6 years old when I replaced it. My friends with external zincs on their propeller shafts replace them once a year.
 

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Zinc - salt water
magnesium - fresh water
aluminum - brackish water

Lots of stuff on line. google .... "anodes, aluminum, magnesium, zinc"
preferably get your info from US mil spec or manufacturers, not the usual internet guru's
 

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Being a new "in the water boat owner" I have no idea how long your standard ball zincs will last. I have a 1" shaft and the PO has 2 ball zincs installed. He was paying for a diver but don't know if he was hauling out once a year.
If he was paying for regular dive service, why would he haul annually?

A diver costs $100 + cost of the zinc(s). A haul and hang (lunchtime for the workers) cost $100... and I put on the zinc. I plan to haul and pressure wash annually on the 2 years between bottom paint.
On what do you base your decision to clean the bottom only annually? Is that the norm in your area? It seems like that is not what the PO did.

In your experience will 2 zincs last an entire year? My marina is brackish.
It is possible to get a year out of two streamlined collar (not "ball") anodes, but you should not expect it. I find 6-9 month anode life to by pretty typical here in the Bay Area. However you go about it, I recommend putting eyes on the anodes no less than every six months. Failure to do so could potentially cost you a lot more than a haul and hang and a set of anodes.



And as previously noted, in brackish water you should be using aluminim anodes.

 

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Are you going to be in exactly the same marina as the prior owner? If not, your experience could be dramatically different. I've had the same boat go through several per year in one marina and almost get away with just one per year in another.

Check regularly.

Now a question for the FB. Do you notice that two shaft zincs provide much more time between needing to change than one? Anecdotally, I haven't.
 
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Being a new "in the water boat owner" I have no idea how long your standard ball zincs will last. I have a 1" shaft and the PO has 2 ball zincs installed. He was paying for a diver but don't know if he was hauling out once a year. Here's my question.
How long depends too much on your boat and where it is docked. If you have a nearby neighbor who's boat is wired incorrectly (or your boat is wired incorrectly) they can be eaten at a rapid rate.

On my boat, with a galvanic isolator and not using shore power at all in the summer months, I get 12-18 months on two 1" zincs. My boat was last hauled in Jan 2013, and was last dove in Jan 2014 (to install a new prop) and the diver reported that my zincs appeared to have more than half of their life left.

A diver costs $100 + cost of the zinc(s). A haul and hang (lunchtime for the workers) cost $100... and I put on the zinc.
Where can you do a hang and haul for $100 in Puget Sound? Does that cover power washing and environmental recovery fees? On a 30' boat it would typically cost about $300 for a hang and haul with power washing. For instance at CSR it is $4.50/ft for the haul, $3.50/ft for the power washing, $50 flat fee for the recovery system, for a total of $290 on a 30' boat. Port of Everett looks like it is $4/foot + $2.75/foot power wash + $35 recovery fee for $237.50.

If you used ablative paint then you can't use a diving service to clean your boat. The fine for doing so in WA is $10,000. You can hire them to change zincs, and that is what many people on my dock do.

I recently bought a cheap underwater camera (Go-Pro-like) to make it easier to monitor my zincs.
 

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Is the primary downside to using multiple anodes increased drag? It would be nice if there were larger (longer) low drag anodes available that had the mass of two regular ones.
 

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In theory, two anodes should provide twice the protection that one does. And in my experience, that seems to generally be the case.
I haven't often done so, but didn't think I got that kind of performance. We've been in the same marina for the past 4 years and I can come very close to making the season on one shaft zinc. I launch April 1 and haul Nov 1. I usually swap it in Aug and the next zinc is pretty good when hauled in Nov.

It would stand to reason, if I installed two zincs in Apr that I would make the entire season without worry. Maybe I will try, but I'm not super confident.

On the other hand, the zinc on the Max Prop goes faster and I can't add another. I don't really understand why, as it is in metal to metal contact with the prop shaft.

Stranger yet is the zinc on the Spurs shaft cutter doesn't corrode much at all, however, does get brittle and still needs to be changed annually.
 

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Is the primary downside to using multiple anodes increased drag? It would be nice if there were larger (longer) low drag anodes available that had the mass of two regular ones.
My guess is that it would take very delicate equipment to dectect any increase in drag between a two-zinc arrangement and a single zinc setup. And considering all the variables that affect boat speed, the difference between having one or two zincs on your shaft is probably the last thing anybody should be concentrating on.

That being said, Martec produces a bullet-shaped zinc that some racers prefer over the streamlined collar type. I suspect it provides little-to-no advantage. I also believe they are made of an inferior alloy, as they definitely don't last as long as the mil-spec zincs I install.

 

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In over 40 years of cruising I have never used a prop zinc, and have never had a problem. My engine is grounded to my steel hull, which has plenty of zincs welded on, and I don't hang out in marinas, with all kinds of AC fields around.
 

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Discussion Starter · #14 ·
In over 40 years of cruising I have never used a prop zinc, and have never had a problem. My engine is grounded to my steel hull, which has plenty of zincs welded on, and I don't hang out in marinas, with all kinds of AC fields around.
Brent, you know what apples and oranges are don't you? :confused:
 

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I started this season with 2 brand new CAMP zincs. I just had my boat hauled after 9½ weeks on a mooring in Greenwich Bay, RI. During that time I have not connected to shore power at all. This is what the zincs looked like.

Yes, the water is brackish, but :eek:
 

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I started this season with 2 brand new CAMP zincs. I just had my boat hauled after 9½ weeks on a mooring in Greenwich Bay, RI. During that time I have not connected to shore power at all. This is what the zincs looked like.
I find Camp anodes to be inferior and I would never put them on a client's boat.
 

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I totally agree about CAMP, but they are what I have...

MUCH better value are B&S zincs.
 
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