The right antifouling coatings save shipping companies billions annually

With more than 90 percent of global trade carried out by sea, ocean vessels need high-performance protection to operate efficiently. When you’re dealing with huge cargo ships carrying vast amounts of product, it becomes all the more important to minimize maintenance, downtime and fuel consumption on every trip.

That goal gets a little tricky when marine life comes into play. Mounds of barnacles and other critters attach themselves to a ship’s hull, slowing the vessel down and making it more expensive to operate.

Those costs make a sizeable dent in a shipping company’s budget. For that reason, commercial vessels rely on special marine coatings to mitigate the expense and deliver shipments more efficiently.

Antifouling is one of the most critical aspects of these coating technologies. When applied to the underside of a ship, antifouling systems prevent marine life from latching onto the bottom of the hull and slowing it down.

While there are tried-and-true antifouling systems on the market, formulators need to keep various factors in mind to create high-performance coatings that deliver on their customers’ demands.

Getting to the bottom of antifouling coatings

Antifouling coatings have a wide range of applications, from recreational watercraft to pipelines, hydroelectric pipes and undersea cables, but marine antifouling systems have specifically drawn attention from operators of commercial vessels, like large container ships, for their cost savings benefits.

The coatings are typically applied first on the original build, and then re-applied every few years as needed, depending on the technology being used.

“When the ship is coated, the special antifouling layer is only painted below the waterline,” says Kyle Kampf, Market Segment Manager for ACE, Marine and Protective Coatings at BASF. “That can include the propeller, the rudder, the inlet pipes — really the whole bottom of the ship’s hull.” Any part of the ship that touches water will be protected from large clusters of marine life that typically attach to underwater surfaces.

The term antifouling refers to any coating that prevents the growth of marine life, but there are a few different ways formulators can achieve that. Many have found success with coatings that use algaecide — like BASF’s Irgarol 1051.

Fouling begins immediately when the surface is exposed to sea water: over time, layers of algae will build up and lay the foundation for larger marine life to grow. An algaecide prevents that from happening in the first place.

 

“Typically, the foulant actually attaches to the algae,” Kampf explains. “As microorganisms build up over time, it creates a biofilm of algae. That’s when you get larger foulants like zebra mussels, barnacles, tube worms, mollusks — there’s a whole plethora of things that could stick to it.”

Kyle Kampf

Market Segment Manager for ACE, Marine and Protective Coatings at BASF

“Typically, the foulant actually attaches to the algae,” Kampf explains. “As microorganisms build up over time, it creates a biofilm of algae. That’s when you get larger foulants like zebra mussels, barnacles, tube worms, mollusks — there’s a whole plethora of things that could stick to it.”

As an algaecide, Irgarol 1051 inhibits photosynthesis to prevent the biofilm from forming altogether, which eliminates the foundation needed for marine growth. Its slow-release format counteracts fouling to varying degrees, depending on the amount and whether the vessel is in static or moving water.

While there are alternatives to algaecide-based antifouling coatings, these aren’t optimized for static water and tend to offer lower performance overall.

According to Kampf, Irgarol’s low solubility in water gives it very slow leaching rates and an extended maintenance cycle.

Marine fouling: Such a drag

There are varying opinions on the amount of money fouling costs shipping companies every year, but the consensus tends to range from billions to tens of billions. A significant proportion of a ship’s fuel efficiency depends on the effectiveness of its antifouling systems.

“Fouling can reduce fuel economy by about 30 to 50 percent over time,” says Kampf. “It creates drag on the bottom of the ship. The propeller doesn’t work as efficiently because the surface is marred, so it’s not moving as much water as it could.”

“It’s a really big drag on fuel economy.”

In addition to fuel expenses, shipping companies must also consider the cost of labor to remove fouling and reapply a new finish, as well as downtime spent in dry dock, among other factors.

That’s why shipping companies rely on antifouling systems to keep ships on the water — and money in their pockets.

“Billions of dollars could be saved by using antifouling coatings,” Kampf says.

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