anodes again

[baggypipes]

hi guys n gals my apologies if this sounds really stupid & thick never thought about it till now as i'm away from the uk & dont want to get wrong ones, having a bit of a language problem so might get sold anything. i'm hoping for sensible answeres. /forums/images/graemlins/frown.gif
apart from different sizes/shapes/fittings is there any diference in anodes that fit onto hull ie does it depend on size of boat etc etc
do different ones perform differently.

 

[VicS]

First consideration is that you use zinc in sea water but magnesium in fresh water and aluminium in brackish.

Bigger anodes last longer but the most convenient thing to do will be to replace with the same size.

The overriding things to bear in mind are that anodes must be fitted fairly close to the items they are to protect, within "line of sight" (but not taken too literally) and be bonded to them with good a good low resistance connection.

Don't bond non ferrous items to the same anodes as ferrous items and remember bronze should not need the protection of anodes at all.

Some useful reading on the MGDuff website

 

[mick]

bronze should not need the protection of anodes at all.

Some useful reading on the MGDuff website

[/ QUOTE ]

I presume my prop is bronze, Does this mean I've been wasting time and money using shaft anodes?

 

[VicS]

[ QUOTE ]
I presume my prop is bronze, Does this mean I've been wasting time and money using shaft anodes?

[/ QUOTE ] If it really is bronze, a copper/ tin alloy, probably yes. But you only assume it is. Manganese bronze is an alloy sometimes used for props. That is a copper/zinc alloy containing manganese and is therefore really only a brass. Props can of course be made from other "ordinary" brasses as well.
It's when someone says that they have just bought a boat X years old with its original prop, which shows no signs of deterioration, and no anodes that one can be quite certain that they do need to add an anode.

If you feel tempted to try to avoid the trouble and expense of renewing the anode you must be prepared to watch out for signs of dezincification and fit an anode if you see any. Alternatively continue to renew the anode as a precautionary measure rather than risk an expensive prop renewal.

Sorry not a lot of help, it's your call at the end of the day, but perhaps that explains the situation. There is however no doubt in my mind that many anodes are sold to people who do not need them.

 

[baggypipes]

thanks for the info vicS very helpfull viited the web sight great help also. hope you didn't think it a stupid question /forums/images/graemlins/smile.gif