Fish type anodes

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Kordie

Kordie

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Aug 7, 2011
144
Beneteau 393 Cruising Baja
So I am thinking of making my own after replacing my anode on the prop after less than 6 months use.

I need a wire cable, a large anode and a place to connect it.

My side stays appear to be earthed. Does this mean I can just hook it up to them or does it need to go elsewhere?

Is there a secret to connecting everything together?

Thanks
 
rardiH36

rardiH36

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Jun 21, 2007
2,118
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
I am a practicing fan of the fish anode concept. But rather than zinc, consider the info within this link. Particularly post #4, which also contains a link (as the end of #4) to another discussion that presents the detail and rationale. My shaft zinc is definitely lasting much longer now that I am also hanging an Al/Indium anode.

http://forums.hunter.sailboatowners.com/showthread.php?p=961010&highlight=aluminum
 
fstbttms

fstbttms

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Feb 26, 2011
1,440
Achilles SD-130 Alameda, CA
Kordie said:
So I am thinking of making my own after replacing my anode on the prop after less than 6 months use.

I need a wire cable, a large anode and a place to connect it.

My side stays appear to be earthed. Does this mean I can just hook it up to them or does it need to go elsewhere?

Is there a secret to connecting everything together?

Thanks
Click to expand
Unless your shrouds are in direct electrical contact with whatever it is you intend the anode protect, you are wasting time and money.
 
A

alexco38

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Sep 25, 2008
1,096
CS 30 Toronto
People try all kinds of stuff without looking at the root cause.

Hanging a zine fish on the side just make more work before and after sailing. Different material only prolongs the change interval.

Newer boat all have galvanic isolator. I put one in 5 years ago. Haven't change the zinc yet. (fresh water, salt water milage may differ). I plugged in at the slip all the time.

Just google what is a galvanic isolator. It originated from the chemical industry.
 
Chuckbear

Chuckbear

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Jan 3, 2009
821
Marine Trader 34 Where Ever I am
These only work if they are securely connected to whatever metal you want to protect. Clipping them on a shroud or stanchion will do little to no good at all. Just because you see them all over the docks doesn't mean they are effective. If your prop zinc is being used up too quickly you need to find out why rather than looking for a quick fix. There are tons of posts on galvanic issues and how to troubleshoot them. There is a problem on your boat or a problem at the dock or a problem with the boat next to you. Find out which. Chuck
 
Kordie

Kordie

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Aug 7, 2011
144
Beneteau 393 Cruising Baja
Chuckbear said:
These only work if they are securely connected to whatever metal you want to protect. Clipping them on a shroud or stanchion will do little to no good at all. Just because you see them all over the docks doesn't mean they are effective. If your prop zinc is being used up too quickly you need to find out why rather than looking for a quick fix. There are tons of posts on galvanic issues and how to troubleshoot them. There is a problem on your boat or a problem at the dock or a problem with the boat next to you. Find out which. Chuck
Click to expand
Taken on board.

If i was to put a loop of wire on an anode and hang it from my shaft when I next leave my boat would it help?
 
fstbttms

fstbttms

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Feb 26, 2011
1,440
Achilles SD-130 Alameda, CA
Kordie said:
If i was to put a loop of wire on an anode and hang it from my shaft when I next leave my boat would it help?
Click to expand
Why not have a diver install a shaft zinc? Your running gear is important and needs to be properly protected. Why are you trying to half-ass this?
 
Kordie

Kordie

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Aug 7, 2011
144
Beneteau 393 Cruising Baja
Diver told me there wasn't enough exposed shaft for a zinc.

Rather than half arse it I am trying to improve what I can.

This is not a permanent berth and I will probably be in a new one this December for some months.

My last prop zinc lasted 4 months which is less than impressive.
 
Kordie

Kordie

.
Aug 7, 2011
144
Beneteau 393 Cruising Baja
alexco38 said:
People try all kinds of stuff without looking at the root cause.

Hanging a zine fish on the side just make more work before and after sailing. Different material only prolongs the change interval.

Newer boat all have galvanic isolator. I put one in 5 years ago. Haven't change the zinc yet. (fresh water, salt water milage may differ). I plugged in at the slip all the time.

Just google what is a galvanic isolator. It originated from the chemical industry.
Click to expand
Researching now, thanks.
 
Chuckbear

Chuckbear

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Jan 3, 2009
821
Marine Trader 34 Where Ever I am
Kordie said:
Diver told me there wasn't enough exposed shaft for a zinc.

Rather than half arse it I am trying to improve what I can.

This is not a permanent berth and I will probably be in a new one this December for some months.

My last prop zinc lasted 4 months which is less than impressive.
Click to expand
OK, That doesn't make sense. You don't have room for a shaft zinc but your shaft zinc only lasted four months? Chuck
 
Kordie

Kordie

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Aug 7, 2011
144
Beneteau 393 Cruising Baja
Chuckbear said:
OK, That doesn't make sense. You don't have room for a shaft zinc but your shaft zinc only lasted four months? Chuck
Click to expand
My prop zinc is on the prop. A shaft zinc is behind the prop on the shaft.

Makes sense to me but then I am not the smartest guy here.
 
jibes138

jibes138

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Jan 27, 2008
3,092
ODay 35 Beaufort, NC
The shaft zinc is connected to the shaft which is connected to the engine which is connected to the negative terminal of the battery. So electrically the negative terminal of the battery is the same point as the shaft. So connect a zinc fish with the clamps that look like the ones on a set of jumper cables to the negative terminal of your battery and chuck the zinc fish overboard. When you leave the dock don't forget to remove it or you might wrap it in your prop.
 
fstbttms

fstbttms

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Feb 26, 2011
1,440
Achilles SD-130 Alameda, CA
jibes138 said:
So electrically the negative terminal of the battery is the same point as the shaft.
Click to expand
Assuming there is no non-conductive spacer (like a DriveSaver) in the drive line, of course.
 
jibes138

jibes138

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Jan 27, 2008
3,092
ODay 35 Beaufort, NC
Good point. Measure the continuity between the shaft and the battery negative terminal first to make sure they are connected.
 
Don S/V ILLusion

Don S/V ILLusion

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Sep 25, 2008
7,594
Alden 50 Sarasota, Florida
Unfortunately a long path to GND can often have multiple connctions as well as the electrical length which combine to add resistance to the path. Remember Ohm's Law.
Just because you find continuity in the path doesn't mean it will be at the same potential as the underwater metals you are typing t protect and if not, you just CREATED another battery.
 
jibes138

jibes138

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Jan 27, 2008
3,092
ODay 35 Beaufort, NC
Don,
I understand what you are saying, but then where would you suggest connecting the fish zinc to? Seems like a shroud would be much further removed from the shaft than the negative ground of the battery making the resistance even greater, not to mention it is stainless and thus not that good a conductor? Connecting it directly to the shaft inside the boat would be very dangerous in event it was forgotten and the engine put in gear. Not only would the wrap be bad but the zinc fish may become a projectile. Or would you suggest just not using them at all and properly maintain the shaft zinc?
 
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