[Anonymous]

I have always fitted the genuine Volvo Penta zinc anode ring, p/n 876286. Apparently this has been discontinued by VP who now supply an aluminium version instead. Given that the saildrive is itself made of aluminium I am worried about fitting an aluminium anode. Does anyone have any advice? As far as I know pattern (i.e. not genuine VP parts) zinc ones are still available so I suppose I could just use those.

I keep the boat in a salt water marina (Fleetwood).

[IanJCulley]

…that’s a very interesting post and so far I’ve had conflicting advice.  A couple of weeks ago I bought all the winterising bits for the 2020D in my B32 Another Fantasy (filters, impeller, etc etc) and also asked for a saildrive anode.  My local dealer told me that the zinc variety had been discontinued and replaced by an aluminium version; when I expressed surprise they said ‘it’s fine, no problem’ but wouldn’t be drawn when I asked how an aluminium anode gave protection to an aluminium saildrive casing.  I chose not to buy it before seeking more ‘expert’ advice but there seems to be no clear answer, some say ‘ok’, others say ‘not a good idea, stick with zinc’.  I’ll be interested to see if there are any opinions offered here!!

Ian Culley

[Anonymous]

I have researched ‘elsewhere’ too and have nothing definitive. So far:

1. The nee aluminium one ‘will be fine.’ What the suppliers mean when they say this is that it will be fine for THEM, not necessarily for us. I asked Keypart specifically and they didn’t know what I was talking about; they’re good, but understandably chiefly concerned with selling what they have to sell.

2. Would VP market something that wasn’t suitable? Some suggest that the aluminium anode is actually a mix of various metals, including aluminium, and it ‘should’ be OK.

3. I wonder to what extent VP are thinking of 20-year-old saildrives when they market anodes? We don’t all have new saildrives.  People like me cannot afford any possibility of an eaten-up saildrive.

4. Some folk say that if you change away from zinc for one anode you should do the same for any others. I have a supplementary zinc pear anode for my MS25S and a Bruntons Varifold with zinc anodes (which dissolve in no time). Others say that because the prop & saildrive are electrically isolated it doesn’t matter if the saildrive is protected by an aluminium anode and the prop by zinc.

5. Like you I didn’t buy an aluminium anode. I don’t know what to do, really. At the moment I feel that I will buy a pattern zinc one but I have always in the past valued the ‘reassurance’ of fitting one that costs a lot and comes in a nice blue box.

[JohnDisney]

An interesting and informative article on zinc vs aluminium anodes has been published by :

https://citimarinestore.com/citiguide/when-to-use-zinc-anodes-over-aluminum-anodes-on-a-boat/

worthy of a quick look. It explains the pros and cons of each type.

[Author]

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