We attach a new zinc anode to the shaft of our Beneteau 323 at the beginning of every season. When we pull our boat out in the fall the anode is always gone. We've made sure it's screwed on extremely tightly and last summer coated it with Loctite Thread Locker and it still came off. It's a substantial anode and the boat is only in the water for 3 months so I'm sure it hasn't disintegrated - any suggestions?
Disappearing zinc anode - Beneteau 323
- Thread starter chrisbeneteau
- Start date
I'm assuming it's falling off - but I don't know why it is. That's my assumption because I don't know anyone else who has an anode that disintegrates in 3 months.
Have you considered that YOU may have an electrical issue that is causing it to disintegrate? Do you ever dive on your boat mid season to check on condition? Sounds to me that its doing its job...... you may want to keep an eye on it during the season and monitor its demise. I dive on my boat to check all zincs several times per season.... last thing I need is my shaft / prop falling off.
Good Luck!.
Good Luck!.
If there is a lot of galvanic activity near your boat or on your boat, it could disappear quite quickly.
The best way to check is with a silver chloride anode and a digital volt meter.
www.boatzincs.com
Then then it is a process of tracking down the specific cause. Do you have shore power? Do you have a Galvanic Isolator? If so, is it working?
The best way to check is with a silver chloride anode and a digital volt meter.
Corrosion Reference Electrode (CRE) with User's Guide
Corrosion Reference Electrode (CRE) with User's Guide | BoatZincs.com | America's Superstore for Marine Anodes
www.boatzincs.com
Then then it is a process of tracking down the specific cause. Do you have shore power? Do you have a Galvanic Isolator? If so, is it working?
Testing A Galvanic Isolator - Marine How To
A 30A Galvanic Isolator WARNING: The galvanic isolator used in this article does not meet the current safety standards. To meet the current safety standards you would need a "Fail Safe" unit that has been tested to the ABYC Fail
marinehowto.com
Do you have play in your cutlass bearing. Not sure if that could cause it to be thrown with time but sounds reasonable to me.
Are you sure it is the correct diameter for your prop shaft? Even severely deteriorated anodes I'd find difficult to Imagine there is not a trace of the anode left after three months. If indeed that were the case - I would think your prop would also show deterioration.
How many years have you had this boat? Where do you keep it? How many years has the disappearing zinc been happening? What diameter shaft do you have? What diameter zinc are you putting on? How's your prop? What material is the shaft made from, and what materal is your prop?
'tis indeed strange...
dj
We keep our boat on a mooring in salt water all season, it's never hooked up to shore power so I don't think it's an electrical issue. The shaft and prop look fine.
I am no marine electrical genius but I always assumed if your boat has a faulty grounding issue you could be the cause of zinc destruction...... shaft and prop would be fine because they were saved by your zinc. Maybe a real electrical guy on this site can confirm or clear me up on that....... I can't see the zinc just falling off..... I've never seen nor had that happen and it seems like you are going the extra mile to secure it. Good topic Love to learn.
NYSail - I'm with you. From a high level there are really only 4 possibilities.
1) the zinc is actually deteriorating enough to disappear in 3 months.
2) the zinc is falling off.
3) the zinc is being stolen, or removed by a third party for what ever reason.
4) the OP is playing with us and none of this is real.
So if it's point 1), the amount of current necessary to remove the entire zinc without trace would be greater than the zinc would be able to protect the prop, especially with the fine leading edges unless there was the incredibly unique condition that the boat was inspected as the zinc fell off on its way to the inspection point.
Point 2) - I have also never seen this happen. I can't imagine a properly sized and installed zinc could just fall off. So on this one I'm at a loss. Could a too large zinc spin on the shaft and wear through and fall off? Are they installing the zinc incorrectly somehow? That's about all I got on that one...
Point 3) - Well, I have seen some very strange things happen in Marina's, to be honest. Is there someone angry or jealous with this boat owner? Or someone that is just playing a weird prank? These things I have seen.
Point 4) I have simply included this one for completeness. I guess it could be possible. But why would they do this? (OP - please do not be offended).
dj
I asume you mean a donut zinc, and not the one on the end of the shaft? I use the donut on my B323, a 25 mm. You need the one that is maybe 7/8 thick? I once got a zinc that the screws were a bit long, so I bent them so they could not unscew.
That would be great. If you can take a photo showing overall geometry and then some good close-ups of the zinc and it's location. Especially where the old zinc was located. Put a new zinc on as you would normally. Take close-up photos of both bolts, from both sides.
Of course, if all this is possible.
dj
Do you also have a Beneteau prop hub zinc?
