Anti-barnacle Boat Hulls
Unless you own a seafaring vessel, you probably don't lose much sleep over barnacles. But for navies, marinas and commercial fishing boats, it's a serious concern. A 2011 study conducted by researchers at the United States Naval Academy found that biofouling -- that's the fancy term used to describe what happens when the small saltwater crustaceans adhere to a hull or propeller and decrease the vessel's efficiency -- costs the Navy $56 million per year or $1 billion over 15 years [source: Schultz]. And that's just for one class of ships -- the Arleigh Burke-class guided missile destroyers.
Most of those costs involve a cleaning and painting process that's been around for centuries. First, the ship is placed in dry dock, then workers scrape the barnacles from the hull and propeller blades. Finally, they treat exposed surfaces with paint containing tin or copper. The metals in the paint are toxic to barnacle larvae, preventing them from settling down and finding a permanent home. But the paint wears off over time, which means ships must be cleaned repeatedly over their lifetimes.
Luckily, scientists have found what may be a better approach. After learning that barnacles prefer smooth surfaces, they created a micro-textured material containing tiny peaks and valleys ranging in size from 1 to 100 micrometers. Then they exposed the material to barnacle-filled seawater to measure how much attachment took place. They found that when the topography of the surface texture remained in the 30 to 45 micrometer range, barnacle settlement and attachment was reduced by 92 percent compared to smooth surfaces [source: Berntsson]. The research may lead to the first nonstick, barnacle-busting ship of the future.