Zinc or aluminium out drive anodes

[Neilthesparky]

Always thought zinc was the way to go for anodes used in salt water, keep seeing aluminium for sale stating use for salt and brackish water.
Which should I go for ?? Going to be moored in chichester marina

 

[Greg2]

We switched to aluminium when we were moored in salt water as we went inland as well. Now moor in fresh and go to sea and still use aluminium. Work well in both. If you are only in salt then not sure it makes much difference although my impression as that Ali lasted a little longer.

 

[Neilthesparky]

We switched to aluminium when we were moored in salt water as we went inland as well. Now moor in fresh and go to sea and still use aluminium. Work well in both. If you are only in salt then not sure it makes much difference although my impression as that Ali lasted a little longer.

Cheers for the reply, they do say the aluminium ones will last longer, should be lighter as well

 

[omega2]

Our first set of ally ones did us two years, on the hull and on the trim tabs, the following set lasted for about 8 months, so a lesson was learned buy from a reputable anode maker, there are some real cheap ally ones out there but not so good as advertised.

 

[GrahamHR]

I was sceptical about using "aluminium" anodes to protect an "aluminium" drive. Neither are the same alloy though.

First year, using VP zinc anodes on my DPH drive, the active corrosion protection unit indicated it was working at maximum capacity.

This year, with aluminium alloy anodes, it's working at normal levels

Hopefully the drive is still there when the boat is put on csore in October, I expect it will be !

 

[Neilthesparky]

Cheers for the replies, I think I'm going to go for the aluminium ones, going to grab some from force 4 tomorrow

 

[omega2]

Cheers for the replies, I think I'm going to go for the aluminium ones, going to grab some from force 4 tomorrow

Go to zincsmart get the real Mcoy

http://www.zincsmart.com/

 

[rafiki_]

The standard theory is zinc for seawater, alu for brackish and magnesium for fresh. What you definitely don't want is anodes lasting nicely while your alu sterndrive disappears slowly!

 

[Greg2]

The standard theory is zinc for seawater, alu for brackish and magnesium for fresh. What you definitely don't want is anodes lasting nicely while your alu sterndrive disappears slowly!

I think you are right but as I understand it that is because zinc don't work in brackish/fresh and magnesium don't work in brackish/salt. Aliminium on the other hand work in both fresh and salt, which is why they many use them in brackish....if that makes sense. Our experience has been good so far

 

[Momac]

I have these fitted since the spring...................
http://www.solentanodes.co.uk/collections/aluminium-volvo-anodes
Whether they have done the job remains to be seen.
I am based on fresh with a visits to brackish and salt water - aluminium seems a logical choice for me. Magnesium would fizz away quickly in salt water - zinc would be no good at all in fresh water.
.

 

[Scubadoo]

Just remember not to mixed anodes, so if you going to change from Zinc to Alu you need to change them all.

 

[ian38_39]

from what I can glean there may be a big difference between outdrives and shafts where anodes are concerned.

While we had VP outdrives we used performance metals Nav Alloy anodes. They are not Aluminium they are an alloy that is slightly more reactive than the drive itself in all waters.

We found they worked brilliantly but the ring anodes do tend to need changing a lot more often than the bar anodes as they are a bit thin.

Performance Metals also do OEM for Mercruiser, fitted straight out of the factory for use in all waters.

When it comes to anodes for shafts drives, maybe you really do get aluminium lumps to bolt on as the stories I hear are these fizz away fairly quickly in pure salt.

 

[GrahamHR]

Just remember not to mixed anodes, so if you going to change from Zinc to Alu you need to change them all.

Are you sure about that ? My D4/ DPH has 4 anodes; 2 on the drive ( now Al), 2 pencil (Zn) anodes within the engine compartment. I've not come across aluminium pencil anodes.