I boat in the great lakes (only fresh water) and switched to magnesium
anodes last year instead of zinc. After one season (5 months in the
water) the magnesium anodes are completely shot. They are riddled with
holes and are falling apart. The zinc anodes took years and years to
look this way.
I know that's what's supposed to happen, but is it possible something
is wrong if they deteriorate so quickly? I'm putting a new pair on
this week for this new season, but I didn't expect to have to change
them every year.
By the way, it's a 30 foot cruiser with twin Volvo duoprops so I have
to change 4 anodes total, 2 for each outdrive.

One more thing, someone told me to add a round, disc anode to each
stainless trim tab and that it would work better.

Ideas, comments?

Thanks

Big Daddy wrote:
I boat in the great lakes (only fresh water) and switched to magnesium
anodes last year instead of zinc. After one season (5 months in the
water) the magnesium anodes are completely shot. They are riddled with
holes and are falling apart. The zinc anodes took years and years to
look this way.
I know that's what's supposed to happen, but is it possible something
is wrong if they deteriorate so quickly? I'm putting a new pair on
this week for this new season, but I didn't expect to have to change
them every year.
By the way, it's a 30 foot cruiser with twin Volvo duoprops so I have
to change 4 anodes total, 2 for each outdrive.

One more thing, someone told me to add a round, disc anode to each
stainless trim tab and that it would work better.

Ideas, comments?

Thanks

You have stray current someplace. My dockmate is on his 3rd year with
magnesium (Lake Ontario)

Ask you marina to check for stray electrical current in the water. They
should last longer than a year.




"Big Daddy" wrote in message
oups.com...
I boat in the great lakes (only fresh water) and switched to magnesium
anodes last year instead of zinc. After one season (5 months in the
water) the magnesium anodes are completely shot. They are riddled with
holes and are falling apart. The zinc anodes took years and years to
look this way.
I know that's what's supposed to happen, but is it possible something
is wrong if they deteriorate so quickly? I'm putting a new pair on
this week for this new season, but I didn't expect to have to change
them every year.
By the way, it's a 30 foot cruiser with twin Volvo duoprops so I have
to change 4 anodes total, 2 for each outdrive.

One more thing, someone told me to add a round, disc anode to each
stainless trim tab and that it would work better.

Ideas, comments?

Thanks

"Big Daddy" wrote in message
oups.com...
I boat in the great lakes (only fresh water) and switched to magnesium
anodes last year instead of zinc. After one season (5 months in the
water) the magnesium anodes are completely shot. They are riddled with
holes and are falling apart. The zinc anodes took years and years to
look this way.
I know that's what's supposed to happen, but is it possible something
is wrong if they deteriorate so quickly? I'm putting a new pair on
this week for this new season, but I didn't expect to have to change
them every year.
By the way, it's a 30 foot cruiser with twin Volvo duoprops so I have
to change 4 anodes total, 2 for each outdrive.

One more thing, someone told me to add a round, disc anode to each
stainless trim tab and that it would work better.

Ideas, comments?

Thanks


You are using the correct type of metal.....magnesium is the choice for
freshwater.

Here is some useful information on corrosion, galvanism and electrolysis you
may want to read:

http://yachtsurvey.com/corrosion.htm

http://yachtsurvey.com/corrosion_in_marinas.htm

http://yachtsurvey.com/SternDrive.htm

On 20 Apr 2005 09:15:14 -0700, "Big Daddy" wrote:

I boat in the great lakes (only fresh water) and switched to magnesium
anodes last year instead of zinc.

The new rage is titanium anodes. Try them, they work great.