Originally Posted by fstbttms
"Don’t Mix Anode Types. If you install different anode materials
like zinc and aluminum, the more active anode (aluminum) will
spend part of its effort protecting the less active metal (zinc). This
will reduce the overall protection that you are getting."
fst - Thanks for the link. I read it fully.
Inboard boats with mainly bronze and stainless metal parts can be protected using zinc or aluminum anodes
. Don’t worry about overprotecting them. You are only overprotected when the weight of the anodes is so great that your boat sinks! The voltage generated by zinc or aluminum anodes will not cause any damage – no matter how much anode material is added, the maximum voltage that can be generated is the voltage of the anode itself. You could also use magnesium in freshwater locations on fiberglass-hulled boats. Be careful using magnesium on aluminum or wooden hulled boats since you can overprotect them. Steel hulls can also be overprotected to the point where excessive protection voltage rapidly lifts the paint off the hull.
Aluminum - The Final Winner
! In our opinion the best all-round anode material is aluminum. Consider these points ! • Aluminum anodes are more active than zinc and are accepted by the major Sterndrive manufacturers as the best material to use. • Aluminum anodes are not so active that they are dangerous in salt or brackish water as are magnesium anodes. • Aluminum anodes will last longer because of their increased current capacity. • Aluminum is the only anode material that can be used safely in all types of water. • Aluminum anodes are 2 Ĺ times lighter than zinc making them much easier to carry home from the store! • Aluminum is a much better alternative than zinc as far as the environment is concerned, since it is not considered a pollutant.
Don’t Mix Anode Types
. If you install different anode materials like zinc and aluminum, the more active anode (aluminum) will spend part of its effort protecting the less active metal (zinc). This will reduce the overall protection that you are getting. A classic mistake is adding a zinc transom anode to a Sterndrive equipped with aluminum anodes. Transom anodes are connected through the bonding system so make sure you install aluminum replacements.
Sooo... Am I correct to think that magnesium anode diver's dream would be eaten faster due to its added need for protection of the aluminum anodes on shaft/rudder? And... that all anodes therefore would give reduced protection to the bronze and stainless and steel water surrounded portions.