Leisure 27
Well-Known Member
My anode is about a 3rd rotted away. How small should I let it get before fitting a new one. My boat stays in the water for 11 months per year. Am I wasting money to change it this year. Should i wait till it is smaller.
When to fit a new anode
- Thread starter Leisure 27
- Start date
Tranona
Well-Known Member
Depends on how long it took to wear away the third. It will remain effective as long as there is zinc on it. However if that wastage was in one year then it is not unreasonable to expect it to last another year at least.
My saildrive anode has wasted around 50% in 2 1/2 years so will probably replace next year.
My saildrive anode has wasted around 50% in 2 1/2 years so will probably replace next year.
Ningaloo
Well-Known Member
I have been advised that you should measure the anode erosion by weight rather than a visual inspection. Difficult to do on a boat.
Surface area will get smaller as it erodes.
I would advise you to replace it, especially if it is protecting something like a stern drive leg.
Surface area will get smaller as it erodes.
I would advise you to replace it, especially if it is protecting something like a stern drive leg.
guernseyman
Well-Known Member
As a rule of thumb replace it when half the weight has gone.
If that occurs in one year you need to think about a bigger anode.
If that occurs in one year you need to think about a bigger anode.
Tranona
Well-Known Member
Not difficult to estimate either weight or volume that has been wasted, particularly with regular shape anodes. surface area is misleading as wasting usually creates crater which can result in an increase in surface area.
Important thing is the time the anode has been on to estimate wastage rate.
Important thing is the time the anode has been on to estimate wastage rate.
Porthandbuoy
Well-Known Member
I usually replace mine when the legend M G DUFF is no longer legible. Takes about three years with seven months afloat each year.
claymore
Well-Known Member
They are not expensive - the cost of replacing/repairing the stuff damaged could be considerable - swap it!
Leisure 27
Well-Known Member
Thanks for your reply,s It as been on for 4 years
RichardS
N/A
If it's only a third gone in 4 years and the boat comes out of the water every year, I would probably leave it for a couple more years as it's not doing that much, which is good news. However, I would change it if I had to do some other work on the area, such as changing the shaft seals in a saildrive or removing a prop.
Richard
capnsensible
Well-Known Member
Top tip. Save pennies, waste pounds.
Tranona
Well-Known Member
Useful rule of thumb, but really not relevant here as the anode has only lost a third in 4 years, so really does not need changing yet.
capnsensible
Well-Known Member
To assume a uniform rate of wear is a small risk. But one that I personally dont take with my boats. Oh, one boat now!
However, fill yer boots.
Sybarite
Well-Known Member
At about £10 an anode it's chicken feed compared with other boating costs. I change the shaft anode every time I antifoul the hull. If the old one still has some life in it I leave it on too.
RichardS
N/A
colind3782
Well-Known Member
+1 :encouragement:
[163233]
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Keypart are quoting just shy of 60 quid for a full set of 110S anodes.
https://www.keypart.com/volvo-penta/saildrive/110s
PhillM
Well-Known Member
I have found that I can safely go down a couple of anode sizes, providing that I change it every year. Being wooden she comes out in the summer .... and there can be summer discounts to be had 
