Anodes & Antifoul

Anodes are critically important to your boat. Our Operations Manager Shane Subichin takes the time to explain why…

What is an anode?

An anode is a sacrificial block of either zinc or aluminum alloy that is mounted on, or connected to, the underwater metal parts of your boat E.G. stern drives, shafts, propellers, rudders, trim tabs and skin fittings. Anodes come in a variety of shapes and sizes.

Anodes & Antifoul 2What do anodes do?

Anodes are designed to sacrifice themselves by depleting first, rather than expensive parts of your drive or underwater metal fittings. Stern drives, underwater propulsion gear and hull fittings are made up of two or more types of metal. Galvanic corrosion is an electrochemical reaction between two or more different (or dissimilar) metals submerged in seawater. Anodes connected to these metals are more galvanically active and will corrode before the vital parts of your vessel.

Are your anodes corroding as they should?

Vessel owners need to be aware of the location and condition of sacrificial anodes mounted on their boat. Many owners don’t realize the corrosion damage that can occur to stern drives and under water metal fittings if anodes are not regularly maintained or replaced.

Why is it critical to check and maintain anodes?

Generally sacrificial anodes need to be replaced when 50% consumed. Correct corrosion protection to vital boat parts is not achieved if anodes are left to deplete below 50%. Generally the size and amount of anodes installed to each moored vessel are designed to last up to 12 months. However, many factors can contribute to anodes depleting at a faster rate including; water temperature, salinity, water current flow, stray electrical current and vessel or jetty wiring faults. Therefore, checks are often required monthly, quarterly or six monthly checks to determine the depletion rates of sacrificial anodes.

Anodes & AntifoulAny other advice?

  • Upon purchasing your vessel check for signs of corrosion and condition of anodes as soon as possible.
  • Obtain maintenance history to determine when the anodes were last changed.
  • Determine your vessel and jetty electrical systems are in good order.
  • Consult your local vessel and engine / drive package dealer for specific requirements.

Note: This is a general guide only. If you would like personalised advice regarding anodes, contact Shane on 07 5500 0000.

He’ll be able to help you and/or direct you to a professional team onsite for further action. It is recommended you contact your local boat or engine service dealer for specific requirements for each vessel and engine/drive package.