Sea Technology

JUN 2018

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www.sea-technology.com June 2018 | ST 33 which are extremely strong and perform well in polar environments. "Most Navy surface ships currently have propellers made of an alloy of nickel, aluminum and bronze, called NAB," said Kim. "When considering alternative materi- als, we need to trade off between manufacturing cost and performance to reach an optimized solution, because stainless steel and titanium are more difficult and expen- sive to manufacture than NAB." International Partnerships Most of the Arctic research efforts featured in this arti- cle involve international collaboration. This is by design. ONR, together with its international command, the Office of Naval Research Global, has been a key player in the recent establishment of the International Cooperative Engagement Program for Polar Research (ICE-PPR). This proposed framework between the United States, Canada, Denmark, Finland, Iceland, New Zealand, Norway and Sweden is part of ONR's answer to the requirements of the Arctic Roadmap. Several research areas will be front and center for ICE- PPR, including human performance, platforms and the environment. While the U.S. Navy has much to bring to the table—including its own existing research programs and extensive submarine experience beneath the Arctic Ocean—it also has much to learn from the cold-weather operational experience and capabilities of other nations. Looking Ahead The Arctic is a daunting, fascinating frontier—ripe with potential benefits for those who study it and apply its lessons carefully. Acquiring knowledge of this impos- ing region will ensure the safety and effectiveness of fu- ture scientific activities, improve forecasting capabilities, and expand the operational reach of surface vessels. Naval science and technology research efforts are al- ready embracing this challenge. ST Warren Duffie Jr. is a writer and editor at the U.S. Office of Naval Research. Hefty Hulls ONR program officer Dr. Roshdy Barsoum is oversee- ing hull research that builds on an ancient idea: ice belts. Since the earliest days of polar exploration, sailors used iron bands or double wooden planking around ship waterlines to traverse treacherous Arctic waters. Today, ice belts are made of durable, hardened rubber compos- ites. Barsoum sponsors work at NSWC Carderock dealing with "polymer sandwiches" as a type of ice belt. In this sandwich, a section of a ship's outer hull would be cov- ered with a strong, lightweight layer of polymer materi- al—similar to a truck bedliner—encircling the waterline. This layer then would be sheathed underneath a rein- forced steel plate, creating a cushioned barrier against ice. Engineers at NSWC Carderock test the sandwich's fortitude using a machine that drops heavy weights on separate steel plates, some strengthened with the poly- mer layer, some not. The weight is dropped at different speeds and intensity to mimic the force of ice collisions. Plates fortified with the polymer withstand the hits with less dents or buckling. Barsoum hopes to fund future tests at CRREL, as well as outfit a retired Navy ship for Arctic trials. "The tests at Carderock have been very successful, but they've been conducted at room temperature," he said. "Steel becomes more brittle in extreme cold, so it's im- portant to test the plates and polymers in the most realis- tic conditions possible." Powerful Propellers In addition to ice-phobic coating, Ki-Han Kim spon- sors research to assess the vulnerability of existing ship propellers in Arctic waters and quantify the risks to ves- sels and their propulsion systems. Under a project agreement between the U.S. Depart- ment of Defense and the Ministry of Defence of Finland, the American and Finnish navies are investigating ways to improve propeller design, including alternative manu- facturing materials like stainless steel alloys and titanium, Open architecture cOmmercial it standards mOts military- hardened OppOrtunities tO include technical innOvatiOns yOurself allOwing rapid change and insertiOn Of new capabilities Sea proven submarine sonar suite www.wartsila.com/elac udt 2018, stand e40 WÄRTSILÄ CONNECTS THE DOTS Wärtsilä ELAC KaleidoScope is a sea proven sonar suite designed for conventional submarines. The OpenSonarSuite is a high performance and low risk solution. The owner will be able to maintain and enhance the sonar independently from the industry.

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