Bravo III anode question

[dicor]

Can anyone explain why Mercury recommends Aluminum anodes for Bravo III but Zinc anodes for Bravo I & II?
Also should I use aluminum anodes on my trim tabs?
My boat will be in a wet slip , saltwater all season with shore power hooked up and a working Mercathode.
I searched the previous posts but was unable to find the answers to these concerns.
Thanks in advance.

 

[Lazy Daze]

Because of those two, big SS props. Lot's of dissimilar metals going on there. B1 only has one SS, B2 has an aluminum prop (big, but Al).

Check with your local experts (people that have had at least a few years of experience in your area) that have similar boats/drives to yours. See what they're using. Al might be the best choice (it's always the safest choice, regardless of water, if you're not sure - hence the recommendation), but Zn might in fact be better. Best thing is to check with those locals. And, be sure they are not simply saying "zincs" as a generality.