Sonar Transducers News

Propspeed, an innovator of underwater foul-release coatings, received an endorsement from FarSounder, a pioneer in navigation and obstacle avoidance systems, which has tested the Propspeed Foulfree foul-release coating and recommends it for application by their customers, dealers and partner shipyards.“Our unique, patented technology is designed to paint a clear picture of what lies ahead underwater and along the bottom,” said Cheryl Zimmerman, CEO, FarSounder. “Marine growth on our transducers could limit the effectiveness of our products and potentially put a vessel in a hazardous situation.

Last week, the Dutch governmental shipping company Rijksrederij (part of the Dutch Ministry of Infrastructure and Environment, Rijkswaterstaat) took delivery of its scientific research vessel Tridens after an extensive refit at Damen Maaskant Shipyards Stellendam in the Netherlands. Tridens underwent a major midlife conversion to boost the vessel’s multifunctional capabilities for fisheries research, including installation of a ‘drop keel’. The Rijksrederij is the custodian of the North Sea and manages a fleet of specialist vessels.

Naval Surface Warfare Center (NSWC) Carderock received a patent Nov. 13 for their discovery and development of a new smart material called Galfenol. Galfenol is a magnetostrictive smart material that can be used in sensors, actuators and structural supports. The material was co-discovered in 1999 by NSWC Carderock and the Department of Energy's Ames Laboratory and has been in development for the past 13 years in partnership with Etrema Products Inc. "By itself, iron has the characteristics to be considered a magnetostrictive material…

Seakeeping refers to motions of a vessel in waves, but sea-kindliness is a characteristic sought after in most vessels. A sea-kindly vessel is easy on its crew and easy on its gear. Trying to define sea-kindly is difficult. The deep sea mariner may use qualitative descriptions such as "an easy roll" or "a wet boat," but the vessel designer must look for quantitative descriptions. There are six degrees of motion in a vessel, three are linear: surge, heave, and sway; three are rotational: pitch, roll, and yaw. Each of these degrees of motion has associated values of amplitude, velocity, and acceleration. A vessel in a beam sea can be rolling up to 30 degrees (amplitude) and the associated acceleration could be 0.5 g or 1 g.

The U.S. Court of Appeals for the Second Circuit ruled that a sonar test engineer comes under the coverage of the Longshore and Harbor Workers’ Compensation Act (LHWCA). In the instant case, the engineer spent about 40% of his time conducting tests on sonar transducers onboard a barge permanently moored in Cayuga Lake in upstate New York. Cayuga Lake is connected by locks to the Erie Canal, which is connected by locks to both the Hudson River and Lake Erie. Even though Cayuga Lake does not currently support interstate commerce, the court held that, since it is physically capable of such support, the lake is navigable for purposes of the LHWCA.