Shaft anode clearance problem

Oct 9, 2008
1,742
Bristol 29.9 Dana Point
I seem to find these odd issues a lot.

I've always had to have collar zincs cut to fit the prop shaft. The zincs are 1 1\4" width, and clearance between the prop and rudder skeg (shaft exposure) is about 1 1\8". So have to cut - Extra $, aggravation for the diver, and sometimes the cut zinc wobbles the shaft a little.

I've tried to find limited- clearance collars that will fit, but none seem to exist. So am looking at the Beneteau-specific zincs, which have a width that would work, but they're metric. Mine is a 1" shaft, so am wondering if anyone has used a 25mm collar on a 1" shaft. Or other ideas. I've heard verbally that Cape Dory owners have had a similar issue, but I've found no remedy online.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
boatzincs.com is one source. 25mm and one inch are interchangeable for most applications.
 
Feb 26, 2011
1,440
Achilles SD-130 Alameda, CA
I seem to find these odd issues a lot.

I've always had to have collar zincs cut to fit the prop shaft. The zincs are 1 1\4" width, and clearance between the prop and rudder skeg (shaft exposure) is about 1 1\8". So have to cut - Extra $, aggravation for the diver, and sometimes the cut zinc wobbles the shaft a little.

I've tried to find limited- clearance collars that will fit, but none seem to exist. So am looking at the Beneteau-specific zincs, which have a width that would work, but they're metric. Mine is a 1" shaft, so am wondering if anyone has used a 25mm collar on a 1" shaft. Or other ideas. I've heard verbally that Cape Dory owners have had a similar issue, but I've found no remedy online.
A Beneteau 25mm limited clearance collar will work adequately in your situation.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
Looking at a ruler, I see one inch is slightly larger than 25mm. If 25 does not look like a good fit to your shaft, maybe get a drum sander 1" bit to put in your drill to open it up A LITTLE AT A TIME.
 
Last edited:
Jun 2, 2007
404
Beneteau First 375 Slidell, LA
25mm and one inch are interchangeable for most applications.
I have to disagree here. I have a 25mm shaft, and I found that 1" zincs were a loose, sliding fit. I also don't think you'd be able to clamp a 25mm zinc onto a 1" shaft, even though the shafts are indistinguishable to the eye.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
I have to disagree here. I have a 25mm shaft, and I found that 1" zincs were a loose, sliding fit. I also don't think you'd be able to clamp a 25mm zinc onto a 1" shaft, even though the shafts are indistinguishable to the eye.
He has a one-inch shaft, so opening up the 25 zinc would work.
 
Sep 15, 2009
6,244
S2 9.2a Fairhope Al
the 25 mm zinc is about 16-18 .000 smaller than the 1 inch so it will work going from 25 mm to 1 inch but not the other way
 
Feb 26, 2011
1,440
Achilles SD-130 Alameda, CA
I also don't think you'd be able to clamp a 25mm zinc onto a 1" shaft...
A hammer is a great persuader. :D

Look- nobody is saying a 25mm anode on a 1" shaft is an ideal solution. But in the OP's case, it is a solution, and one that will work.
 

capta

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Jun 4, 2009
5,072
Pearson 530 Admiralty Bay, Bequia SVG
Shaft zincs come in all shapes and sizes. You do not need to use an egg shaped zinc. Also there are many zincs available that cover the prop nut and can just be screwed into the end of the shaft with a one time thread cutting cost.