The Facts About Anti-fouling Paint

7 Facts About Anti-fouling Paint | Every boat owner should Know

Marine coating has always been a popular and demanding method to protect the ships from early erosion. And antifouling paint is mainly used for such coating. Antifouling paint performs tremendously in resisting abrasion, sand making the ships more durable and faster. However, a proper understanding about the facts about anti-fouling paint is very important if you are planning to apply a marine coating.

No worries, we have covered all the authentic facts below so that you get a clear-cut idea about antifouling paint. So, be a couch potato and go along with us.

The Facts About Anti-fouling Paint

Whether you are a new or experienced boater, you need to know the details about anti-fouling paint to take care of the boat or make it durable. Otherwise, the fouling may reduce the life of your precious boat.

To understand the factor about anti-fouling paint, you need to understand several trams. We will present detailed information in this article.

  • What is Anti-fouling Paint?
  • How Anti-fouling Paint works?
  • The benefits of using Antifouling paint on a boat
  • Types of Anti fouling paint
  • The four basic ingredients of an Antifouling paint are

What is Anti-fouling Paint?

Antifouling paint is a specialized underwater coating applied on the hull of a ship to prevent the growth of marine fouling such as barnacles, algae, shellfish etc. which affect the durability and performance of the ship.

Plus, the anti-fouling paint also works as an armor against the hull corrosion protecting the metal from deterioration and weakening. As a result, it enhances the water flow passing the hull which increases the speed of the ship.

How Anti-fouling Paint works?

The self-polishing resin along with the biocide of Antifouling paint prevents the marine growth on the underwater surface of the ship.

The self-polishing copolymer simplifies the renewal of the surface consistently. At the same time, it releases biocide at a constant rate that goes through hydrolysis reaction with the seawater for diffusion.

This process of biocide protects the surface from the growth and attachment of biofouling organisms.

The benefits of using Antifouling paint on a boat

If marine plants grow and settle on the hull of a ship, it will cause corrosion and degradation of the underwater surface. So, the Anti fouling paint acts as a barrier to halt the growth of the fouling organism on the hull. The benefits of using such specialized coating are immense.

  • Antifouling paint prevents the hull from corrosion. As a result, the performance of the ship increases.
  • It helps the ship to move faster while consuming low fuel. Thus, the amount of CO2emission decreases along with reducing the cost.
  • Protects the propeller of the ship from getting damaged.
  • Supports the engine inlets and outlets to function properly. So, the ship can sail through the long sea for a prolonged time.
  • Prevents the fouling agents from the settlement and attachment on the hull of the ship.

The four basic ingredients of an Antifouling paint are:

Anti-fouling paint is made of mainly four basic ingredients and they are as followed

  • Biocide
  • Resin
  • Solvent
  • Pigment

For more than 100 years the main biocide elements that are used during the antifouling formulations are Cuprous Oxide and Metallic Copper.

Cuprous oxide prevents barnacles and mussels from getting attached to the underwater surface of the ship. Besides, it also works superbly as an antimicrobial opposing the growth of slime and grass. However, to work as an antimicrobial to prevent such foul it requires a higher rate of release.

The antifouling paint can also control weed fouling by combining the cuprous oxide with a boosting biocide in the formulation. This type of antifouling paint is considered as the best one.

Moreover, Cuprous oxide can be found in multiple colors starting from dark red to dark purple.


This ingredient helps to form the coating film by grasping the products all in one place. Plus, the resin is the prime and only ingredient that controls the release of copper or other biocides. It determines what type of performance will be achieved by the antifouling.


The characteristics of the antifouling paint are determined by the Solvent ingredient. Plus, it also decides the flowing as well as the drying speed of the paint.


The amount of toxicity needed by the antifouling paint to prevent the settlement of marine growth is determined by the pigments.

Pigment plays a vital role in providing the color along with hardening the coating of antifouling paint. Without this ingredient, ships would never be seen in versatile colors. Plus, it also determines the thickness of the antifouling.

Types of Anti fouling paint

While antifouling paint is important to protect ships, yacht, it is also important to know which kind of paint coating should be applied. So, the most commonly used antifouling paints are elaborated below for better understanding.

  • Hard Antifouling
  • Soft or Ablative Antifouling

Hard Anti-fouling

The best part of hard antifouling is that it does not decay quickly. However, the abrasive element in the water like silt and sand do minor degradationto the film build.

Besides, the release rates of the biocide in hard antifouling go downhill gradually from beginning to the end time of the product. Plus, a residual pile-upsettles on the coating after passing some seasons which need to be removed properly.

A fast boat owner should use hard antifouling paint as it does not erode in freshwater easily. Also, this type of hard painting works best for the racing boat. Because it can be burnished to give a smooth finish before racing for providing fast movement.

Soft or Ablative anti fouling

Eroding antifouling is also called as soft or ablative antifouling. Though it works as same as the hard antifouling by releasing the biocide, it steadily erodes in saltwater. As a result, no trace of paint is leftover on the hull.

While wiping the hull it is noticed that the product is washed away in a small amount. However, this type of eroding antifouling is suitable for people who do not like to go for high maintenance.

Whereas, one thing that lacks in soft antifouling that you cannot scrub it. But this one is much cheaper than hard antifouling.

Self-Polishing Copolymer Anti fouling

There is a well-known subgroup within eroding/ablative antifouling named as self-polishing copolymer antifouling or in short SPC.

A very complex chemical composition is used in making these types of antifouling. The best part is thatover overtime it facilitates the renewal of the hull to make it smooth. Basically, that’s the reason for calling it self-polishing antifouling. Moreover, it protects the hull from erosion by releasing biocide in a very controlled amount.

Since large vessel owner prefers maintenance after a long time interval, these types of antifouling paint are best for them.

What is TBT and Why was it banned?

TBT is a bio-resistance with a much brighter anti-fouling property than shipwrecks in the 1970s because it prevents the growth of algae, barnacles, and other marine organisms. Harmful effects of TB cause disruption of the endocrine system of marine shellfish.

It disrupts the immune system and the harmful system of shellfish shells. Because of the impact on the marine ecosystem and biodiversity, IBO has phased out TBT since January 1, 2008. IBO has phased out TBT since January 1, 2008.

The IMO regulations regarding anti-fouling paints become stricter day by day. Due to that Paint manufacturers continue to work to produce better eco-friendly anti-fouling paints. Already several bands of anty-fouling paint lunch on the market, which are much more eco-friendly.


How much bottom surface should I paint?

Ans. You need to measure the hull that remains below the water line to determine how much you should paint. A tried and true formula for calculating the area is

Length x Beam x 0.85 = Approximate Surface Area sq. ft

It is recommended to apply two coats of antifouling paint for the best protection.

When can I splash the boat after the application of coating?

All the manufacturers mention the amount of time to wait after the antifouling paint application. However, we suggest to hold back for at least one night after you apply the antifouling paint. Otherwise, the coating will wash away with the water.

Do I need to paint if my boat remains out of the water?

No, you don’t need to paint the hull if your boat doesn’t remain in the water. We recommend to give 1 or 2 antifouling coats if a boat remains underwater for more than several weeks.

Wrapping Up!

Above, we have discussed all the essential factors related to anti-fouling paint so that you can get the best out of the paint. Because we want every shipowner from a small boat to a large vessel to go a long way with their ships.

Hopefully, you will be understanding as well about the facts about anti-fouling paint.

Happy boating!

You may also like to read Best Bottom Paint for Boats

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