Cathodic Protection for Marine Hull Protection: What Do You Need?

Cathodic protection for boats and ships is a simple process that can prevent extensive damage to the hull. It is estimated that over 50% of all boat repairs are due to corrosion of the underwater portions of vessels.

Such damage can run from several hundred dollars to replace a few Detroit pencil zinc anodes or over thousands if more extensive damage has occurred.

What is Cathodic Protection?

Cathodic protection (CP) is used to protect metal structures from corrosion. It works by providing an electrical current to the metal, which creates a shield against corrosion.

The CP system uses sacrificial anodes made of zinc or aluminum to provide this current. The anodes are connected to the metal structure, and when they corrode, they provide the current that protects the metal.

How Does It Work?

The CP system works because corrosion is an electrochemical process. When a metal corrodes, it loses electrons. If you can provide a steady flow of electrons to the metal, you can stop or slow the corrosion process. The sacrificial anodes do this by corroding instead of the metal structure.

Why Zinc Anodes?

Zinc is a common choice for sacrificial anodes because it is relatively cheap and has a high corrosion rate. This means it will erode quickly, providing a steady flow of electrons to the metal structure. Aluminum is also a common choice for sacrificial anodes and commercial dive plates, but it does not corrode as quickly as zinc.

How Many Anodes Do You Need?

The number of anodes you need will vary depending on the size and type of boat or ship. Generally, you will need one anode for every foot of the boat’s length. So, a 20-foot boat would need 20 anodes. You can also use anode calculators to help you determine the number of anodes you need.

The anodes should be placed on the underwater portion of the boat, as close to the metal structure as possible. The best way to do this is to use a scanning electron microscope (SEM) to find the areas suffering from the most corrosion.

Which One Should You Choose?

Detroit pencil zinc anodes are a great way to protect your boat or ship from corrosion. They are easy to install and provide a steady flow of electrons to the metal structure, preventing extensive damage. If you are looking to protect your marine vessel, Detroit pencil zinc anodes are the best option available.

Another great option is commercial dive plates. These are made of aluminum and have a higher corrosion rate than zinc. This means they will corrode more quickly, providing a steady flow of electrons to the metal structure. They are also easier to install than zinc anodes, making them a great choice for boat owners who don’t want to deal with the installation process.

If you own a boat or ship, you need to take precautions to protect it against corrosion. The best way to do this is with cathodic protection. There are two options available: zinc and commercial dive plates. Both will provide the necessary protection; however, dive plates are more effective due to their higher corrosion rates.