Sacrificial Anodes - Hull, Propeller, Shaft, Engine & More
Sacrificial anodes are small pieces of metal that are designed to corrode more easily than the other metal components on a boat. They are typically made of zinc, aluminium, or magnesium. They are generally attached to the hull, propeller shaft, or other metallic parts of the boat.
The main purpose of sacrificial boat anodes is to protect the boat's metal components from galvanic corrosion. Galvanic corrosion occurs when two dissimilar metals are in contact with each other in the presence of an electrolyte (such as seawater), and a current flows between them. This can cause the more active metal to corrode. This can then result in costly damage to the boat's engine, propellers, and other metal parts.
By attaching sacrificial anodes to the boat's metal components, the anodes will corrode first, before the other metal components are affected. This sacrificial corrosion means that the anodes will eventually need to be replaced. This is a small price to pay for the corrosion protection they provide on more expensive metal components on your boat.
It is important to regularly inspect and replace sacrificial anodes as needed. They will become depleted over time and lose their protective properties.
Selecting the correct type will depend on where you mainly use or keep your boat. The general rule being:
- Zinc anodes are suitable for salt water use
- Aluminium are suitable for salt or brackish water
- Magnesium anodes are suitable for fresh water use
Force 4 Video Guide: Boat Anodes - Everything you need to know and how to install