Anodes are generally made of magnesium, zinc, or aluminum, materials that corrode more easily than other metals used in boats, such as stainless steel or aluminum. These materials are chosen because they corrode preferentially, thus protecting the boat's other metal parts.

Function of the anodes

Anodes act as "expendables," meaning they are designed to corrode in place of other metal parts on the boat that might otherwise be damaged by corrosion. The galvanic effect that occurs when various metals are immersed in saltwater can cause accelerated deterioration of metals such as stainless steel, aluminum, and copper. By placing an anode near these metal surfaces, the corrosion process will occur first on the anode, keeping the other parts of the boat intact.

Types of anodes

Magnesium Anodes : They are used in freshwater environments, where corrosion is more intense, and are very effective against metal erosion.

Zinc Anodes : These are the most common in saltwater environments and are ideal for protecting engines, propellers and other metal parts.

Aluminum anodes : These anodes are used in saltwater environments, particularly for aluminum boats. They offer effective protection and have a longer lifespan than zinc anodes in certain situations.

How are anodes used?

Anodes are generally mounted in areas where the boat's metals are at risk of corrosion, such as:

• Outboard and inboard engines
• Propellers
• Rudders
• Engine shaft lines

It's important to monitor the condition of the anodes regularly, as they tend to wear out over time. If the anodes are too worn, the corrosion protection is no longer effective, and damage to the boat's metal parts could occur.

How to choose the right anodes?

The choice of anode type depends on various factors, such as the type of vessel, the type of water it sails in (fresh or salt), and the specifications of the engine or other metal parts to be protected. Furthermore, the anode must be sized appropriately to ensure it has sufficient capacity to protect the metal surfaces.