Ahoy Feetup, Iam not sure what you mean by
the main anti galvanic ground term.
A zinc is used to stop galvanic action between dissimlar metals. Like the prop (bronze) and a stainless shaft. They are also used on outboards and for protection of the aluminum and stainless parts .
Don't get bonding and grounding confused, they are two seperate issues. If you could please expound on the term you used.