Chemistry Corner – Important Questions to Ask When Choosing Anti-fouling Paint 5

In marinas everywhere, terrible predators currently reside, just waiting to do damage.  They have names like “Styela,” “Undaria,” and “Mediterranean Fanworm.”   Their mere presence can disrupt sensitive ecological conditions, disrupt wildlife, and create hazardous swimming and boating conditions for humans as well. Of course, these organisms aren’t large animals lying in wait, but rather examples of a growing subset of species that can cause untold havoc and destruction if not properly addressed. The best way to combat these pests isn’t through harsh chemicals or traps, but rather by using anti-fouling coatings and products to keep an infestation problem from starting in the first place.

To the layperson that hears the word in conversation, “anti-fouling” may be dismissed as something that sounds dangerous to birds.  But to the industrial paint professional, it takes on a much more serious meaning. Antifouling coatings and products are those used to keep harmful bacteria off of surfaces, primarily boats and other marine vessels.  The damage caused by the above mentioned kinds of bacteria, algae, and animals can be varied.  From damaging the substrate of a ship’s hull over time to inadvertently transporting different types of bacteria and fungus to new locations around the world, not properly protecting the surface of ocean liners, recreational watercraft, and all sized vessels in-between can lead to catastrophic results.

Antifouling is critical to substrate protection

A painter works on a ship’s hull. Image courtesy of West Marine

Regular cleanings while docked can help keep ship surfaces safe, but that usually only addresses areas above the waterline. Keeping the massive steel hull clean below the water requires preventative measures, which is where you come in. Antifouling coatings have long existed for the benefit of either repelling or killing harmful bacteria, algae, and particles. In addition to protecting the substrate from physical damage, proper antifouling measures help keep the hull smooth, which can have a noticeable effect on draft and fuel consumption by the vessel.  Most paint professionals that work with watercraft understand that choosing the right paint means ensuring that anti-fouling measures are part of the pre-job planning process.

Choosing the correct anti-fouling paint is dependent on a number of factors. When bidding or planning work on a boat, pier, or structure that may be in water, you should gather the following information and consult with your paint supplier about the right chemical compounds needed to provide the best possible protection:

Anti-fouling paint is essential to hull protection.

An improperly protected hull. Image courtesy of SailFeed.

  • What is the substrate made of?  Different anti-fouling paints react differently to steel, iron, wood, and aluminum. For example, aluminum hulls need specialized paint as conventional paint will quickly damage the substrate, defeating the purpose of offering protection through coating.
  • What are the local environmental regulations when it comes to paint? Some locales do not allow certain biocides or compounds in aquatic areas in an effort to preserve wildlife and maintain water quality.  Make sure the paint or coating you choose does not violate any rules, regulations, or laws.
  • Do you need a bright finish or is color unimportant? Some anti-fouling paint requires thick coating to be effective.  This thickness effects the color choices available using these particular products.  Find out from your client exactly what their wishes are with regard to appearance so that you can focus on choosing a paint from the right family of anti-fouling products.
  • Is the structure/boat to be kept in the water year round, or does the paint need to hold up when out of the water as well?  As you can imagine, some anti-fouling paints work great for surfaces that remain covered in water most of the time. Others are versatile enough to protect a boat during a summer on the lake but hearty enough to protect the hull from corrosion or other damage when pulled out of the water and stored for winter.
  • Is the structure/boat in saltwater or freshwater?  Saltwater can have a drastically different effect on substrates than fresh water.  The chemical and environmental nature of the water itself will go a long way in determining which protective product is best for your job.
Every submerged surface needs protection

Boat blades encased in algae. Image courtesy of Custom Floats

Anti-fouling paint relies on the proper mix of chemicals within the paint coating reacting the right way with the sometimes unpredictable and ever-changing chemistry of the water around it. While choosing the right anti-fouling coating can seem challenging, the reality is that it is essential to protecting your client’s property.  Be it organisms that damage precious ecosystems or chemical reactions that lead to rust and corrosion, protecting a submerged substrate from damage should be at the top of your priority list when taking on paint jobs that come in contact with water.  If that isn’t reason enough, you should also know that legions of aquatic wildlife and recreational water-lovers will be thankful that you were so diligent in doing a great job.  Click here to learn more about protecting substrates through chemistry!


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