Below the Waterline: the Tangled Task of Choosing Hull Paint

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The color options are limited, only red or blue. Royal Caribbean chooses blue because it is “aesthetically pleasing on a white cruise ship as it shines underwater when the sunlight falls on it.”

That’s the only simple decision in selecting the paint used on the hulls of RCL ships, says Anshul Tuteja, director of energy management, fleet optimization for global marine operations. Besides the aesthetic choice he describes, the very waters in which the vessels sail complicate all others.

“There’s a lot of chemistry behind these paints and that is where it gets a little bit complex,” Tuteja explains. “It’s actually these chemical characteristics that make a paint either good paint or a bad paint.”

 

The coatings serve a vital purpose in RCL’s efforts to prevent various forms of sea life from sticking to the hulls – referred to as “fouling.” This increases drag, which requires the ships to burn more fuel, a very expensive proposition that also increases emissions.

“If my paint is not able to prevent fouling, it will cause an exponential rise in fuel consumption for the next five years,” the standard time between dry docks, Tuteja says. “The cost of the paint might be $300,000. But the cost of fuel could easily exceed $5 million in the next five years because of the added resistance.”

Another complexity: With some 50,000 ships – including freighters and other commercial vessels – sailing the globe, there’s fierce competition for their hull-coating business.

“There are 10 big international players that can serve their customers not just within the periphery of their origin country, but also globally,” Tuteja says. “It’s a very cutthroat competition.”

Sometimes a company might relabel its old product trying to pass it off as new. Others may claim great performance with little to back it up. So RCL demands tests, data, testimonials and more. It can cost upwards of $1 million to blast the old paint off a hull – a new type of coating can’t be applied over the old one – and repaint it. If it doesn’t perform properly, the line has to live with it until the next dry dock because of the expense of taking the ship out of service and redoing it. Tuteja likens it to being stuck in a bad marriage. “That’s why the coating decision has to go right the very first time,” he says.

An important partnership with Maersk, the world’s largest container shipping outfit, helps narrow the field. RCL exchanges coating data with the shipper to their mutual benefit.

One big difference, however, further challenges RCL: Shipping company vessels generally travel fixed routes; cruise ship itineraries commonly change from one part of the world to others.

“You might have a ship today sailing in Alaska, in cold waters, and the next year in tropical areas,” Tuteja says.

Different types of hull fouling occur in different seas, requiring a coating that comes as close as possible to working well wherever. No existing paint performs perfectly in all environments.

So Tuteja and company continue to look because, simply put, paint is not just paint.