How often should a sacrificial anode be replaced on a boat?

A sacrificial anode is an important component in protecting boats and other marine structures from corrosion. The frequency of replacement depends on several factors such as the type of metal of the boat and anode, the quality of water it is operating in, and the amount of use the boat gets.

In general, sacrificial anodes should be inspected at least once a year and replaced when they have corroded down to 50% of their original size or weight. For boats that are used heavily or operate in highly corrosive water, anodes may need to be replaced more frequently.

It is important to follow the manufacturer's recommendations for the specific type of anode and boat to ensure maximum protection against corrosion. Regular inspections and replacement of sacrificial anodes can help to prolong the life of a boat's metal components and prevent costly damage.

In order to ensure your anodes not only provide the correct level of protection, but last as long as they should, it's vital that you purchase the correct metal for the water your boat is kept in.

Let's take a look at three metal types:

Aluminium Anodes:
Unlike magnesium and zinc anodes, aluminium anodes perform extremely well in both salt and fresh water. Aluminium is also the lightest of the three alloys and has the highest nominal electrical capacity, so you will require fewer anodes than you would zinc or magnesium to cover the same area.

Magnesium Anodes:
Magnesium is an extremely reactive metal, so magnesium anodes are highly recommended for use in fresh water, but will be of little use in salt water. 

Zinc Anodes:
The classic choice for boat builders, zinc anodes are suitable for use in salt water and, although are far heavier than aluminium anodes, will corrode more evenly without visible craters.

Where can I purchase sacrificial anodes?

Since 2009 we've been supplying a leading range of anodes for all areas of your boat; whether that be hull anodes, shaft anodes, engine anodes or even saildrive anodes - you name it, and we'll supply it! However, if there is a mystery anode you can't find on our website, do not hesitate to contact us and our highly experienced team will be on hand to help. You can call us on 01634 568011 or email [email protected].