My anodes are eroding.....

[Nick2]

......at a reasonably rapid rate...

Since March of last year my bowthruster one has gone and there are whapping great chuncks gone out of the ones either side of the shafts.

The trim tab ones not too bad but the marina man was quite suprised by the wastage of the main ones - prob at least 70% gone I would guess.

Is this normal and should I take any other precautions (keeping boat out of the water is too extreme even for me)

Thanks

Nick

<hr width=100% size=1><A target="_blank" HREF=http://arweb.co.uk/argallery/Nick2>http://arweb.co.uk/argallery/Nick2</A>

 

[longjohnsilver]

Well that's what they're there for. Just change them if less than about 25% left and stop worrying!!!

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[Col]

Mine have gone since Sept.

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[hlb]

Ah a customer. Just pass this way to the Good News thread. A product just for you!!

<hr width=100% size=1> <font color=blue>Specializing in marine sanitation since 1997.<font color=red> I'm a volunteer!!.<font color=blue>

Haydn

 

[BarryH]

Do youknow thats amazing. I've had the same ones for years. In fact they were fitted to the boat when I bought it. Never had to change them!

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[boatless]

..but seriously, you could try a voltmeter between your boat's earth and water, and between mains earth and water, I've seen up to 2.5 volts in Hamble Point (was losing folding props every few months because the metal around the retaining screws was gone), changed berths, end of problem.

Look at this too, more potential worries (sorry) <A target="_blank" HREF=http://www.ybw.com/cgi-bin/forums/showflat.pl?Cat=&Board=ym&Number=499681&page=2&view=collapsed&sb=5&o=93&part=>http://www.ybw.com/cgi-bin/forums/showflat.pl?Cat=&Board=ym&Number=499681&page=2&view=collapsed&sb=5&o=93&part=</A>

<hr width=100% size=1>my opinion is complete rubbish, probably.

 

[Johnnygil]

Barry

I agree had the same ones for years just had to keep changing boats every 6 months

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[Nick2]

I generally tend to have the shorepwer lead connected but without power except when I was running heaters etc during the winter.

Is this therefore likely to speed up the process?

Thanks

Nick

<hr width=100% size=1><A target="_blank" HREF=http://arweb.co.uk/argallery/Nick2>http://arweb.co.uk/argallery/Nick2</A>

 

[boatless]

Sorry, not an expert in the black art of cathodic protection, but, if your mains connection and engine ground are common, and if marina mains earth is not zero, it could make the problem worse. Follow that? I think I do.

Voltmeter will tell, but be very careful when checking mains earth. If a neighbour has a current leak, you risk a shock.

<hr width=100% size=1>my opinion is complete rubbish, probably.<P ID="edit"><FONT SIZE=-1>Edited by boatless on 19/04/2004 22:03 (server time).</FONT></P>

 

[Geoffs]

I keep mine outo f the water, like barry have had same anodes for years!

Galvanic current around marinas are common, leading to rapid loss of anodes, or more expensive bits. Do you have a galvanic isolator fitted, to provide a DC break between boat ground and marina ground, but maintain earth continuity for AC protection.

<hr width=100% size=1>Old Chinese proverb 'Man who sail boat into rice field, soon get into paddy'

 

[Nick2]

I dont think that I have an isolator fitted and having seen the wastage I think I should look into getting one. I dont mind losing the odd anode but i wish to keep my other metal bits in tact.

Thanks

Nick

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[nicho]

Nick,

When we had the S37 in Hythe, we too had very little of our anodes left after a year - probably around 30%. I was told that the seawater in/around Hythe is very "aggressive" (?), and erosion rate is high - we tried disconnecting shorepower whenever possible, but it didn't seem to make much difference. Having said that, we've just had the Bav out of the water after 15 months in, and the saildrive anode had a lot of meat left on it.

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[Medskipper]

It goes to show that your anodes are doing the job they are supposed to do!
There is always a lot of electrolosis happening in marina waters because of all the power on the pontoons, but it is also caused by 12v escaping from other vessels around you!

For years I have always unplugged shore power when not at the boat and have always had plenty of "meat" left on the anodes. This year for the first time ever I decided to leave it plugged to the power as I had heaters on board and a dehumidifier.

I have just had the boat lifted and I have lost at least twice as much zinc from the anodes and one of my shaft anodes has disappeared completely! So if you leave the shore power on for the winter months you will need to replace anodes every year!

I have done quite a bit of research over the years regarding this matter and I can tell you that the anodes almost do not erode during use of the boat, i.e. when under wey, so it has nothing to do the how often you use the vessel!

Regards

Barry


<hr width=100% size=1>I just want to retire with my boat to the Med!

 

[smee]

Have you got Copperbot or a neighbour who has?

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[hlb]

Stick two anodes on each shaft. Only way I found to stop replacing shafts every year. Mind, shafts are nearly as cheap as anodes../forums/images/icons/laugh.gif

<hr width=100% size=1> <font color=blue>Specializing in marine sanitation since 1997.<font color=red> I'm a volunteer!!.<font color=blue>

Haydn

 

[PaulF]

Nick, I had a definate increase in anode errosion when I had batteries on charge unless the batteries were isolated from the boats system.

There will be a connection to your system earth (shafts etc) to one side of your battery, there probably should be when the system is 'live' and under way for example. When ithe batteries are being charged you will almost certainly affect the errosion. If the shorepower is just left connected you may be creating what is referred to as an 'earth loop'. The actual potential difference of different earth points creates current flow and 'thats wot eats yer anodes' . Disconnecting shorepower unless charging may reduce the erosion. If in doubt, get a marine sparks to check it out. Anodes are cheaper than propellors, but you still dont want to fry them away overnight! Good huntin' Paul

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