Yacht Antifouling - deterring marine growth

Ablative and non-ablative Anti-fouls

What is ‘fouling’?

Fouling normally occurs on surfaces below waterline and its where marine organisms attached themselves. This is normally done during there infant ‘stage of growth’ and they attach in areas most suitable considering current, light and available nutrients.

The first to attach is slime, which in itself is a bacteria made up of organisms, then follows the ones we are more familiar with such as weed or barnacles (to mention just two).

The result is drag (resistance to movement – resulting in slower speed), gradual increased weight (due to the growth on the bottom), but the most important is the damage that can be caused by not monitoring this growth. Left unattended, some organisms such as tubeworm's can cause havoc with the vessels structure, eventually requiring extensive costly repair work.

Common Anti-fouling

Studies have found that two common compounds inhibit (not stop) the attachment of ‘fouling organisms’ and they are tributyltin or copper. Either (or sometimes a mixture of both), are added to paints that are then spread over the ‘below waterline’ areas of the vessel. We are informed that the ‘tributyltin’ types will outlast the copper based products by 2-3 times. Having said this, ‘tributyltin’ (and some tin) types have been banned from use in many areas (since early 2000 in Australia, due to their destructive nature on the marine environment, so its back to the copper based types for the foreseeable future.

Some antifoul's now include Teflon, it supposedly makes the surface more smooth making it more difficult for organisms to attach.

We are aware of three common forms of Anti-foul:

  • Ablative paint types (paint that slowly ‘wears/washes away, theoretically supplying a new surface),

  • Non-ablative paint types (epoxy paint that sets hard), and

  • Electronic types (these include the ‘ultrasonic’ brands).

We spoke to a few companies of which two allowed us to make contact with their ‘Technicians’. In the end, we chose to stick with Wattyl for their price and assistance. This decision was prudent and has paid dividends, it however needs to be said that we have not tried other brands.

While the names may have changed, we used Epinamel PR250, Sigma EP Multiguard, Sigma EP Tiecoat and Sigmaplane Ecol HA120 (Red and Blue in colour). We understand that legislation has changed and so has the product content from all manufacturers. Wattyl now brand these products under the Seapro Marine Range and we have used their Seapro CU120 since the launch.

Our initial antifouling applications are detailed here in DIY Catamaran Pure Majek. We believe this to be the solid foundation that has since allowed the ease of applications since the yacht was launched.

The availability and cost of Wattyl has forced us to look at alternatives. On the test bed at the moment is ALTEX No5. It was compatible with the older Wattyl product and application appeared easier and quicker. The mixing too was much easier. The product came in a handy 10-Liter container, which is perfect for application.

While it may be seen as excessive, we used both the epoxy and then ablative paints on Pure Majek. We often moor in a known 'high tubeworm' area and took step as additional insurance. We have closely followed the progress of this anti-fouling process and have catalogued this for those interested via a short video above.


Our Antifoul Review

Brand   Ease of Application & Clean-up   Appearance   Test Period   Our Rating (10)
Wattyl   6/10   8/10   5 Years   6.5
ALTEX No5   7/10   8/10   1 Year +   7

Facts, Figures & Further reading:

  1. ALTEX No5 Marine Coatings

  2. Wattyl Seapro Marine Coatings Range