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I have just replaced my 3 blade origanal prop on my B38, becourse it is eaten away.
This has only hapend in the last six months, since I last lifted her out, when the prop
was ok.
I have replaced the ally prop with a Kiwi prop, so should not have problems with electrolisis,
but I am now concerned about my sail drive leg. How do I protect it from being eaten away.
I have an anoid on the bottom where the prop goes on, but do I need more protection.
How do I do this in laymans terms please!!Hi Bill, that sounds quite alarming in such a short space of time….
Had anything else changed during that period? i.e. did you leave the boat plugged into shore power etc?I left CaSam plugged in all winter with heaters and a dehumidifier on and it ate the anodes in a matter of months….. since then I only leave her plugged in when I am on board and need it and the erosion has almost completely stopped.
Alternately do you have any “new” boats around you that were not there before that may be adding to the problem?
As for addiding more protection, you will need the boat out again and fix perhaps a pear shaped anode or similar to the hull and then use a bonded strap back to the leg.
My first view though is, if it did not do it before you probably had the right protection so look to see where the fault lies and fix that rather than over engineering what has worked in the past.
Not directly related to electrolysis…. but I would be very interested to know what you think of the Kiwi prop and, in particular, what sort of speed improvement you achieve when sailing. Our boat is a Bavaria 32 with a fixed 2 bladed prop.
You first need to check if by accident you have electrically connected the saildrive to the engine. So get a meter and check the isolation of the two from each other. If the saildrive is isolated there should be no reason for concern.
If you are concerned about electrolosis via the mains hook-up to the marina then fit a Galvanic Isolator in the earth wire.
@SERENDIPITY wrote:
If you are concerned about electrolosis via the mains hook-up to the marina then fit a Galvanic Isolator in the earth wire.
CaSam has a factory fitted galvanic isolator……. it was still a problem
Bill, did you get to the bottom of this?
We made a change (on Aibrean) to our procedures this year and disconnected the shore power lead whenever we were not on the boat. We have just (October 2012) taken Aibrean out of the water and noticed that the erosion on the earting anode was very much less this year than previously. Coincidence perhaps, but we will continue to disconnect the shore power lead when not needed.
Hi, You got me a bit worried on this when I first saw it. I’m going to fit one of these from Sterling Power looks like it might fix it click the link or paste it in your your browser, if you don’t think it will fix it please could you let me know as it seems Sterling have!
@CaSam wrote:
@SERENDIPITY wrote:
If you are concerned about electrolosis via the mains hook-up to the marina then fit a Galvanic Isolator in the earth wire.
CaSam has a factory fitted galvanic isolator……. it was still a problem
Bump…
When Playtime was left in the water over the winter, I didn’t use the shore power socket on the boat. I ran a cable reel from the pontoon straight into the cabin and plugged the dehumidifier and tube heater straight into sockets on the reel, by-passing all the boat circuits.
On my new boat I have a factory fitted galvanic isolator but still route the shore power cable direct to the dehumidifier/heater for the winter.
If you do the same make sure that whatever is plugged in is completely isolated from any metal (or water) in the boat that could provide a route to the sea and thus give any potential (love that pun) for galvanic action.
Roger
Thanks for that Casam, I am not pluged into the mains but have a live on board near me with electricity, could that have an influence?
I was thinking about more protection but was told you can have to much, you cant win.
Thanks, Bill]Hi Bill, that sounds quite alarming in such a short space of time….
Had anything else changed during that period? i.e. did you leave the boat plugged into shore power etc?I left CaSam plugged in all winter with heaters and a dehumidifier on and it ate the anodes in a matter of months….. since then I only leave her plugged in when I am on board and need it and the erosion has almost completely stopped.
Alternately do you have any “new” boats around you that were not there before that may be adding to the problem?
As for addiding more protection, you will need the boat out again and fix perhaps a pear shaped anode or similar to the hull and then use a bonded strap back to the leg.
My first view though is, if it did not do it before you probably had the right protection so look to see where the fault lies and fix that rather than over engineering what has worked in the past.[/quote]
Thank you all, I will look at all your points, I am not however plugged into the mains power.
The anode seems to be doing its job. There is a live aboard near me that is using mains power!!
Regards
Bill.
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