how long should anodes last

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lionelz

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Well had my boat serviced today by Jim Davis from Davis marine. Just a bit concerned that when he was changing the engine anodes 3 of the 5 had completely rotted away! They were changed on the service last year. Is it normal for them to completely go like that in a year? The boat is stored on a dry stack and the engine is a yanamar STZP 4. I know they rot as that's what they are designed to do but to completely go for me appears worrying. Just concerned what could happen to the inside now. This year I will do a 6 month check on them just to see. Any thoughts would be appreciated. Is this the more?
 
The answer is a bit "piece of stringish" I'm afraid. It depends on a number of variables. However if your boat is dry stacked, then erosion would be much slower than if permanently moored in running sea water. Are you able to look at the anodes when the boat is lifted for the stack?
 
Is this yanmar an inboard engine? and were the anodes referred to the ones bolted into the engine. If so be thankful they have saved you a fortune. Many do not even know they are there. Excuse my ignorance just looked it up and it is an inboard, I still have Fords LOL READ YOUR OWNERS MANUAL!!
 
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Yes it's an inboard. And the anodes are bolted into the engine. Makes you wonder what goes on. My engineer raised an issue that he thinks one of them may never have been changed in the 10 years of the boat as it still had the original paint on it. I bloody hope note I paid for a full service when I bought it a year ago. At least I know they are good now. Also by watching him it's an easy job and the full set of anodes cost about £34 so if I do have to change then it's not that expensive.
 
Several years ago a mate paid for a full leg service with a well know company based in the Hamble...they have gone bust now..thankfully.

A year later his leg was destroyed by corrosion. On further inspection he found that all of the internal anodes were missing. They simply had not been put in by the company who serviced it.

So he went back and was told to !"£$ off.

It cost him 2k to get a new leg. So when my outdrives get done i will be there so i can learn and then do it myself.

When it comes to underwater or unseen things i don't trust anybody
 
Were they the right type of anode for the water ie zinc/aluminium/magnesium

docanodes2.jpg


http://www.boatingmag.com/how-to/choosing-right-sacrificial-anode
 
Sailorsam101 said:
A year later his leg was destroyed by corrosion. On further inspection he found that all of the internal anodes were missing.
Click to expand...


Curious but what " internal" anodes ???
Anodes on legs are external ! Ring and bar.
There are internal anodes inside heat exchangers etc but not aware of any leg with them hidden away inside anything.
Anodes need contact with water to work.
Now I know that all legs eventually end up with water inside and so maybe manufacturers are just accepting the inevitable.
WARNING ......Outdrives please do not get wet or use near water. :)
 
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lionelz said:
Yes it's an inboard. And the anodes are bolted into the engine. Makes you wonder what goes on. My engineer raised an issue that he thinks one of them may never have been changed in the 10 years of the boat as it still had the original paint on it. I bloody hope note I paid for a full service when I bought it a year ago. At least I know they are good now. Also by watching him it's an easy job and the full set of anodes cost about £34 so if I do have to change then it's not that expensive.
Click to expand...

Like I said NOT EVERYONE KNOWS THEY ARE THERE!! check every 6 months at least, or your cooling/intercooler system will die a horrible death. Now you know what they should look like you can make up your own mind when to change them. The expendable bit can be bought separately. Thats if they are the pencil type. Also if you are in and out the water try to drain the engine as good as possible, any water left will activate the anodes, best thing is to remove the anodes when you are high and dry at least the lowest ones.
https://www.yanmar.com/media/global...ion/operationmanual/4LHA_OPM_49961-205434.pdf PLEASE READ.
 
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To my knowledge, the anodes are in the heat exchangers, where raw water is used to cool the engine coolant. My Cat engines have 10 finger anodes per engine, distributed between the engine, transmission, and intercoolers. Some also have them in the exhaust elbows. My Cats don't.
 
oldgit said:
Curious but what " internal" anodes ???
Anodes on legs are external ! Ring and bar.
There are internal anodes inside heat exchangers etc but not aware of any leg with them hidden away inside anything.
Anodes need contact with water to work.
Now I know that all legs eventually end up with water inside and so maybe manufacturers are just accepting the inevitable.
WARNING ......Outdrives please do not get wet or use near water. :)
Click to expand...

Yawn, the same old hobby horse promoting negatives regarding outdrives. Shaft drives never have problems with corrosion? Why are prop shaft anodes sold then ?
 
GrahamHR said:
Yawn, the same old hobby horse promoting negatives regarding outdrives. Shaft drives never have problems with corrosion? Why are prop shaft anodes sold then ?
Click to expand...

To make use of the broken cases and props littering the scrap yards of our beautiful country. Its called recycling!! LOL
 
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