Antifoul – Hard or Soft?

There are countless different antifouling products on the market produced by multiple manufactures and as a poor innocent sailor your problem is to determine which one is best for your boat. Unfortunately, the combinations and permutations of the different styles and types of antifouling available make an informed selection difficult at best.

Since the demise of TBT (tributyltin oxide or tin) based paints the organic chemists have had to work a bit harder to make their products more efficient. Many antifouls do still contain copper, and whilst there is a global push to have it banned to, its remain available in some antifouls, so without fear of stating the obvious, if you own an alloy boat NEVER use antifoul with copper in it.

Let’s look at the commonly defined two types of Antifoul.

Soft (called ablative copolymers) paint is as its name says is softer when it dries and as your boat moves through the water the top layer of the paint erodes, exposing a new layer of chemically active ingredients to discourage the critters from living on your hull. Soft Antifoul is a good choice for cruising boats that are regularly used and usually simply applied by roller. For cruising boats that are not so regularly used, many will choose the harder version of the soft ablative as the harder types can be scrubbed by owners caring for a swim or by paid divers. When recoating comes around a good pressure wash and rub down will generally be enough preparation for a new coat.

Pro divers in Australia often won’t scrub a boat with soft antifoul as it is illegal to put any bloom in the water from the paint, you can get ‘booked’. Soft or Ablative anti foul last about a year, maybe a bit more, without a scrub and depending on its usage.

Hard antifoul on the other hand does not ablate and as a consequence is slightly more toxic as there is no “wearing” of the layers. The Hard antifoul produces a hard and smooth finish (normally applied by spray gun) that reduces water resistance. This finish can be cleaned regularly without sloughing off paint into the water. This smooth finish is most often used by race boats and also trailer sailors where a hard finish that can better withstand a few knocks is required. Whilst the hard is superior when chasing performance through the water the downside are the preparation and application is generally more expensive, and over years you will get a build-up that will required to stripped right back at some point and start again.

NOTE: Some antifouls will not play with others. You need to know what is on your boat and check to see that the new antifoul is compatible.

Thanks for reading this far we hope this has been of some assistance to you. Safe and “slippery when clean” sailing to you all.

– David Burt

David heads up our YOTI Race division.