Why use hull anodes for cathodic protection?
The primary purpose of hull anodes is to protect your hull from corrosion, making the maintenance of your boat easier. So how does this work? Let us take you through it all.
When metals get under water (for example your hull), a corrosion process starts (the rusting process), simply explained it means that the metal tries to return to its origin in a raw form. In the process of making the metal, a lot of energy is added, energy that then wants to be released. The only way for the metal to release all the energy added is by corroding, which then becomes the cause of your hull rusting.
This means that your hull will eventually be consumed. This can be avoided by using hull anodes, also known as sacrificial anodes.
A sacrificial anode is a piece of alloyed metal that is attached to a metal surface, such as a boat hull. When the anode is attached to the hull by either screwing or welding, it gives off a protection that prevents your hull from corroding. The alloyed metal that the hull anode is made of, becomes the metal that will be consumed and will also take the damage, so that your boat hull stays intact. Protecting your hull with sacrificial anodes will therefore be a cost-effective solution that will save you from expensive maintenance and repair costs.
Which metal in which type of water?
Depending on the type of water your boat is in, the effectiveness of the metals is different. The different metals (sacrificial anodes) perform differently depending on the type of water they are placed in. Not sure which hull anode to use in which type of water? See our explanation below.
For optimal protection on your hull that is in salt water, Aluminium anodes is the right choice for you.
In fresh water however, we recommend Magnesium anodes for the best possible protection of your hull.
For brackish water which is a mixture between fresh and salt water, we recommend the use of our Aluminium anodes or Zinc anodes. This is because it is difficult to determine how salty or fresh the brackish water is without any water samples. Fell free to contact us
if you have any doubts.
There are several important factors that must be considered before choosing the type of sacrificial anodes. For example, the size of what you want to protect, other parameters such as painting/coating is also important. Should you need help calculating the number of anodes to protect your hull from corrosion, you are always welcome to contact us
with your question. Remember that an anode that has been consumed about 50% from its original appearance and weight should be replaced.
What should I do if my hull is made of a material other than steel?
As not all hulls are made of steel, there is of course a solution for them too. A rule of thumb is to always buy sacrificial anodes with the same insert as the material of the hull. For the sake of clarity, let us give an example:
For a boat with Aluminium hull that is located in salt water, the right product would be a Aluminium anode with Aluminium insert. The reason for this is that the insert is made of Aluminium, which allows the anode to be either screwed or welded to the hull. Aluminium is the substance that performs best in salt water, this is also why the anode in this case should be made of this substance.