Anodes for 3 bladed folding prop

[ashanta]

At the week end I dried my boat out so that I could change a sea cock. As I had the opportunity I checked over my prop that was new this season (I launched begining of April) and was shocked to find that the three anodes which are attched around the circumference of the body of the prop had completely disapeared leaving the alan screws exposed. I tightened the alan screws up and now I have to get new anodes and fit ASAP. Fortunately it is a sail drive cofiguration and the anode on the saildrive is giving me some protection.
Any idea why the anodes would have eroded so quickly? Any forumites with a Volvo 3 blade folding prop experienced this before?
As usual, your feedback will be greatly appreciated.

Peter.

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[charles_reed]

Galvanic corrosion

Before I fitted a shaft anode, the boss anode on my aluminium-bronze feathering prop used to disappear in about 1/2 season.
If your prop is aluminium it's even higher up the anodic scale than my prop.

The shaft anode, at about 10% of the price of the boss anode, now lasts the season, mainly because it contains about x3 the amount of zinc.

Unless you can find the kathode causing the wasting, I'd suggest fitting some supplementry anodes to the propellor.

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[Budgie]

Re: Galvanic corrosion

I have a Volvo saildrive with a two bladed folding prop. There is a hull anode and an annular anode behind the prop on the saildrive leg.

The saildrive anode used to almost totally vanish during the season until I started painting the prop blades with MPX. Since then anode wear has been fairly light.

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[Becky]

Re: Galvanic corrosion

What is MPX and where do I buy it - the usual swindleries?
Any idea how it works?

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[ashanta]

Re: Galvanic corrosion

I still have the anode attached in the usual position on the end of the sail drive. The 3 anodes that have disapeared are ones that are specifically for the 3 blade folding prop. They make up a complete circle by being attached around the circumference of the body of the prop. My previous prop was aluminium.
AS previously mentioned, what is MPX and is it easily available?

Many thanks.

Peter.


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[dickh]

Re: Galvanic corrosion

MPX is the International hard antifouling recommended for boottoppings and props - in my experience pretty useless! Obtainable from the usual chandleries but in a small tin and lasted me 4/5 seasons but as I said, I don't use it any more. I just paint A/F over the boottopping and highly polish and Lanolin the prop.

<hr width=100% size=1>dickh
I'd rather be sailing... /forums/images/icons/smile.gif