Using a marine grade synthetic grease is the way to go! I sound like an advertisment, but AMSOIL is just about the only brand anything I use anymore! It's a bit costly, but worth every penny. Being a mechanic i look at things like the grade's, and additives in oil, grease, trans. fluid. AMSOIL is at the top of the list.
https://www.amsoil.com/storefront/gwr.aspx