How often should I antifoul my boat?

8th March 2021 Eugenie Alder

To ensure that your boat is well looked after, it is recommended that you book in for an antifoul every 9-15 months. This will vary depending on how frequently you use your boat, where it is berthed or moored and the harshness of that environment (for example, in Sydney Harbour you would aim for between 9-12 months).

However, it seems there is still a minority of boat owners out there who push the boundaries in an attempt to save a few pennies. But the reality is, that’s not the case.

Customers who bring in their boat to be antifouled after periods of 18-24 months commonly find more issues with their boat, which ultimately costs them more money in the long run.

Here are a few issues that are often found with boats when you leave it too long to book in for a clean, antifoul and anode replacement:

Fibreglass damage

Excessive growth becomes difficult to remove once the barnacles have stuck to the fibreglass underneath the antifoul.


Sacrificial anodes play a crucial role in avoiding corrosion to all propellers, shafts, stern drives, trim tabs and rudders. If these are not replaced annually the risk of corrosion to the running gear is greatly increased.

Engine Overheating

Raw water intake blockage is one of the most common contributors to an engine overheating. This can be avoided by the clean-out and re-antifouling of all intakes and skin fittings. This is all included in the process when a boat is antifouled.

Fuel Consumption

As the growth underneath the hull continues to build up, so does your fuel consumption. It causes increased drag; in turn, the boat travels much slower requiring more engine power. There have been cases where excessive growth has been responsible for fuel efficiency dropping by up to 50 percent.

All of these issues are seen frequently when antifouling a boat is left too late, months after it is due. The results are costly and can be avoided with a little TLC and monitored maintenance.