Re: Trim Tab anode question
Aluminum is more noble than magnesium. Corrosion will attack the less noble metals first. So, since your outdrive is made of aluminum alloy, you want the less noble magnesium to be eaten first. (There is a 50% chance that I have stated the "nobility theory" exactly backwards, but I think you get the idea, right?)
The reason that Aluminum anodes are offered is because in saltwater, the magnesiums would be eaten up in a matter of weeks, and then your drive would get corroded next. Glad you ordered the mags, that what I used exclusively after the first two years I had my boat slipped in freshwater, and it was ABSOLUTELY worth the extra money!
