Sea Technology

JUN 2018

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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30 ST | June 2018 Home to the nation's primary ice tank facilities, CRREL features 26 deep-cold rooms that can maintain tempera- tures as low as -40° F—as well as large test basins where scientists and engineers can recreate the icy and snowy conditions of the Arctic Ocean. In addition to sponsoring Tuteja's coating research, Kim collaborates with the North Atlantic Treaty Organi- zation's Applied Vehicles Technology Panel—to assess existing anti-icing and de-icing technologies for air and sea vehicles, and recommend ways to improve those technologies. Besides the United States, this partnership includes Canada, the United Kingdom, France, Norway and New Zealand. What Affects Hull-Sea Ice Collisions? Another major Arctic threat is collision with sea ice, which may cause severe dents, cracks and ruptures. To figure out how much impact, or ice load, a Navy ship can endure, ONR's Hess is sponsoring special- ized research at Naval Surface Warfare Center (NSWC) Carderock Division in Maryland. Researchers design ice load prediction models on a sophisticated computer system called ICELOAD. They enter data and equations about the physical and chem- ical properties of metallic hulls and sea ice—and create various computational models outlining how much ice load a ship might encounter during Arctic operations. "The risk of structural damage due to ice load and im- pact depends on many factors, including vessel speed, ice thickness and the shape of a ship's hull," said Dr. Judy Conley, a science and technology coordinator at NSWC Carderock. "Our objective is to characterize this inter- action in the simplest terms possible and determine the most efficient, damage-resistant structure capable of Arc- tic operations." After creating the computer prediction models, sci- entists travel to CRREL to test their accuracy on physi- cal-scale models of Navy ships. Although ICELOAD has been in use since the 1980s, the renewed international focus on the Arctic bolstered a partnership among NSWC Carderock; the American Getting rid of ice buildup is tough work. Current re- moval methods include baseball bats, heavy mallets, scrapers and chemical melting agents. "Not only are these methods labor-intensive or cor- rosive, they can harm high-value equipment like radars and antennas," said Dr. Ki-Han Kim, an ONR program officer. ONR is sponsoring several research efforts into anti-ic- ing and de-icing coatings that can be sprayed on large areas and make ice removal easier. Prominent among these is the work by Dr. Anish Tuteja, a professor at the University of Michigan. Tuteja's team developed a spray-on "ice-phobic" coating that causes ice to slide off surfaces. Thin, clear and composed of synthetic rubbers, the coating operates through a phenomenon called interfacial slippage. Usually, two rigid surfaces—think of ice and a wind- shield—freeze together tightly. That's why scraping ice off a car can be laborious. However, the rubbers created by Tuteja's team display both solid- and liquid-like proper- ties, enabling ice to slip off with very low applied force. This makes for easy and effective ice removal. So far, the spray-on coating has been successful- ly tested at the Army Corps of Engineers' Cold Regions Research and Engineering Laboratory (CRREL) in New Hampshire. (Left) A dangerous coating of ice on the NOAA Ship Miller Freeman in the Bering Sea, Alaska. Such icing can affect a ship's stability and cause capsizing. (Photo Credit: NOAA Library Ship Collection, Courtesy of NOAA NMAO Pacific Marine Center) (Right) During a winter research cruise to the Labrador Sea in 1997, waves washing over the decks of the RV Knorr caused continual ice buildup. It took six to eight people the better part of a day to bang all the decks, bulkheads and bulwarks free of tons of ice. (Photo Credit: George Tupper, Woods Hole Oceanographic Institution)

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