What is the purpose of a sacrificial anode?

The purpose of a sacrificial anode is to protect the hull and other metal parts from corrosion. This is achieved through a process called cathodic protection, where the sacrificial anode, typically made from a more reactive metal such as zinc, magnesium, or aluminum, is intentionally allowed to corrode instead of the underlying structure it is meant to protect.

When two different metals are in contact with an electrolyte, such as seawater, galvanic corrosion occurs, and the less noble metal (the sacrificial anode) will corrode preferentially. This means that it will wear away while the more noble metal, such as the boat's hull or hardware, remains intact and uncorroded. By strategically placing sacrificial anodes on a vessel, boat owners can significantly extend the lifespan of metal components that would otherwise succumb to corrosion over time, thereby enhancing the overall durability and safety of the boat.

The other answer choices do not align with the primary function of a sacrificial anode. Increasing buoyancy, enhancing speed, or serving as a load-bearing structure do not pertain to the corrosion protection role that sacrificial anodes serve.