Anodes

Zinc-based galvanic anodes called tutya are used to protect metal parts of ships that are underwater from corrosion.

Sacrificial anode is a protective piece made usually from zinc alloys that protects the metal parts of boats, yachts, and ships in the maritime industry from saltwater corrosion. These pieces sacrifice themselves to prevent other metal parts from corroding, which is why they're also called 'sacrificial metal' or 'anode'.