How does the presence of galvanic corrosion on a mounting bracket indicate a failure in the sacrificial anode protection system?

Galvanic corrosion occurs when two different metals are in electrical contact while submerged in an electrolyte, such as saltwater, which allows electrons to flow from the less noble metal to the more noble metal. This flow of electrons causes the less noble metal to dissolve, or corrode. A sacrificial anode system is designed to prevent this by placing a highly active, or less noble, metal like zinc or aluminum in th....