How important are new sacrafical anodes?

[KD4UPL]

I've owned my '97 Larson since 2005. I have to assume the anodes on the outdrive are the factory originals. I've heard you should replace them when they loose half their weight. I don't know how much their supposed to weigh and don't have an accurate enough scale to measure it anyway.
Are they really that important for a boat that is rarely left in the water?
My boat, unfortunately, spends most of it's life on the trailer. It gets run on the lake maybe 10 different weekends a year. It gets left in the water, tied to a dock over night maybe 8 nights a year.
Do I really even need to worry about the anodes with such little water exposure? How do I know if they should be replaced or is it just obvious for a 15 year old boat?
I only boat in fresh water so I guess I should replace them with magnesium ones.

Thanks,

 

[josh1981]

Re: How important are new sacrafical anodes?

Yes they are absolutely necessary!!!!! See how they get eaten away? Well if they are not there that would be your outdrive. I have never weighed them. Just look at them if they are about half way gone replace. Look at what new ones look like ( http://www.iboats.com/18-6158Z-Anode-Kit-Zinc-Sierra/dm/*******.678549610--session_id.243087111--view_id.708912 ) if you dont know. Those are for an alpha drive, and are zinc but you get the picture, not sure if that is what you have.

 

[haulnazz15]

Re: How important are new sacrafical anodes?

If you boat in fresh water and trailer it, there's a good chance you'll never replace them. They don't trend to get eaten up very much until you run in salt or leave the boat moored in the water, especially around other boats.