orion
Full Member
Posts: 46
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Post by orion on Jan 1, 2014 11:49:37 GMT
I recently received delivery of a Flexofold 2 blade folding prop which I hope to fit in lieu of my existing two blade fixed prop before relaunch of my SO32i in March. The present situation is that the existing 25mm shaft has two Zinc Anodes, one clamped to the shaft the other at the extreme end of the shaft as shown below. The boat is normally on a swinging mooring and the Anodes last the season. The end Anode would show greater wastage that the shaft Anode. My question is what happens to the end Anode when the folding prop is fitted as there will be is no position for end Anode? Do I fit two shaft Anode any help out there? Attachment Deleted
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Post by MartyB on Jan 1, 2014 19:25:46 GMT
Put two on the shaft. I typically put three and those only last me 6 months or so. As the marina I am in is a bit on the hot side!
Marty
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orion
Full Member
Posts: 46
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Post by orion on Jan 2, 2014 10:50:37 GMT
Thanks Marty,
Could two Anodes cause any problems with Shaft balance, vibrations etc?
Liam
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Post by MalcolmP on Jan 2, 2014 13:52:27 GMT
The anode that is directly attached to the prop will always erode first, due to the better contact and distance etc
Two anodes should not affected balance at all - you could mount them so one has the join vertically and the other horizontal, but it will be marginal.
Make sure you leave a decent gap - I would suggest at least 15mm in front of the cutless bearing as it is water lubricated, I have seen shaft anodes bolted tight up to the P bracket which is not a good idea.
You probably do this anyway, but worth abrading the shaft before fixing to make sure of a good connection and bolt up tightly and possibly add a small squirt of sikaflex or similar to make sure the fixing bolts can't vibrate loose (I once had a shaft anode come loose and in reverse it can wind up the shaft and hit the hull.. not a good idea either
Good luck with the new folder I am sure you will find much better sailing performance
Malcolm
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orion
Full Member
Posts: 46
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Post by orion on Jan 2, 2014 16:31:47 GMT
Hi Malcolm,
Thanks for that advice, I will run with the two Anodes.
Regards
Liam
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Post by ianqv on Jan 2, 2014 18:29:12 GMT
If it helps.... I fit 2 anodes as I also have a feathering prop. Its worth paying more for the good ones (i.e like mc duff) as when they wear down they won't start to slide down the prop shaft. Cheap prop anodes don't have this metal clamp feature (which prevents them from coming loose when they are worn down).
Regards
Ian
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Post by psychotiller on Jan 3, 2014 4:40:35 GMT
For what it's worth, I have a Sun Fast 32i with a factory installed folding prop. I just recently had the boat yard here replace the cutlass bearing and so we replaced the anode as well. The yard only recommended one anode. I would think two is better than one if it doesn't cause any problems. As others have mentioned, it might even be a regional thing depending on how hot the water is in your area. Guess I just need to have faith my slip neighbors have well grounded electrical systems. If you have a good diver who regularly cleans your hull they can usually check the anodes and even replace them underwater if needed too.
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orion
Full Member
Posts: 46
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Post by orion on Jan 6, 2014 12:42:10 GMT
Thanks everybody for your comments.
Psychotiller did the yard say why they recommended only one Anode?
I will probably clean up the existing anode and add a second, as you can see from the first photo there is still a good bit of Anode left after a season. This is probably due to the fact that I am on a swinging mooring with no shore power.
On the subject of Anodes, I have a Yanmar 3YM20 engine, is there engine Anodes I should be looking at on her?
Regards
ORION
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Post by psychotiller on Jan 7, 2014 4:36:14 GMT
That's an interesting question actually. Initially when we pulled her out of the water there was only one anode on the shaft. I wondered if there was supposed to be 2 and asked the yard guys. At that time he said one was fine. I just purchased the boat a few months ago and if it was missing an anode it would not surprise me at all. I've discovered more than a few questionable repairs...or lack thereof performed by the previous owners maintenance man. But I digress, that conversation could last for hours... So, at the time we hauled her out the guys in the yard seemed to think one was not a problem, and the one existing anode did look to be in decent shape. But today I went back and looked at the invoice from the repairs and it shows I was charged for 2 anodes. Due to scheduling conflicts I was unfortunately unable to be at the boatyard when she was put back in the water so I can't say what is there for sure. However I imagine it's safe to assume they ended up putting 2 anodes on there.
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paulreid
New Member
SO37 - Aquae Sulis
Posts: 8
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Post by paulreid on Jan 29, 2014 0:29:20 GMT
I believe the one on the prop is to protect the prop. I put 2 shaft anodes on as well. The McDuff ones have one end tapered and the other flat, so I put them back to back for better flow around the anode.
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