Does anyone use sacrificial anodes? If so, where do you attach them?

I sail exclusively in salt water and have seen some seriously corroded boats.. I would love to avoid this. I sail about 100 days a year on my 1 boat so I want to preserve it as much as I can.

I do rinse off my cat with some freshwater (all the blocks, cleats, travleres, and all areas where dissimilar metals are) every night if I leave the cat on the beach (Friday and sat nights), and bring it through the car/boat wash every Sunday when it leaves the beach.

Thanks,