What metal can be used as a sacrificial anode on a small ocean fishing boat with an aluminum hull?

Using magnesium as a sacrificial anode on an aluminum hull is effective due to its position in the galvanic series. In electrochemical terms, magnesium has a more negative electrode potential compared to aluminum and other metals, which means it will corrode preferentially. This sacrificial corrosion protects the aluminum hull from oxidation and degradation when in contact with seawater.

Magnesium anodes are lightweight and have a good balance of performance and cost, making them suitable for marine applications, especially in saltwater environments. Additionally, the use of magnesium mitigates the risk of galvanic corrosion that could occur if less reactive metals were used, which would not protect the aluminum adequately.

In sum, magnesium is the ideal choice for a sacrificial anode in this scenario, effectively safeguarding the aluminum structure of the boat from corrosion while ensuring a longer lifespan in a challenging marine environment.