ANODES

Why do we do anode replacements? Whenever two dissimilar metals are placed in an electrolyte, like salt water, the metal less resistant to corrosion (base metal) starts to give off electrons to the metal more resistant to corrosion (noble metal). This process is known as galvanic corrosion. If there’s an electrical current within the electrolyte — for example, a stray electrical current from the boat’s electrical system or a poorly connected shore power cable — the rate of corrosion increases. This process is known as electrolytic corrosion. Every time you set your boat in the water, the metals in the outboard or stern drive experience galvanic corrosion and possibly electrolytic corrosion. In other words, your motor is slowly being eaten up, and anodes are designed to keep that from happening. To prevent corrosion, it’s necessary to introduce a base metal that is even less resistant to corrosion than the metals that make up the motor itself. To accomplish this, blocks of base metal known as anodes are attached to the outboard or stern drive.  Anodes are typically made of zinc, which is an extremely effective base metal far less resistant to galvanic and electrolytic corrosion than most other metals. The anodes act as sacrificial metal because they give off their electrons and corrode before the other metals in the motor can be affected. Because corrosion attacks the least resistant metal on a boat’s motor, the anodes or zincs are the first line of defense. Anodes are consumed first to prevent other parts of the outboard from getting eaten up by corrosion — hence why they’re often referred to as “sacrificial anodes”— giving off their electrons to be depleted before any other metals are targeted. Eventually there will be so little left of an anode that it ceases to be effective, which is why they need to be replaced periodically. That's where Paradise Dive Service comes in. We can dive specifically to replace the anodes or replace them while we clean the hull.