Sea Technology

AUG 2012

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

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Amelia Earheart's lost aircraft. Phoenix International Hold ings Inc. (Largo, Maryland) is the expedition's primary contractor. The search, organized by The Interna- tional Group for Historic Aircraft Recov- ery (TIGHAR), is focusing on a reef slope off the west end of Nikumaroro in the southwestern Pac ific Republic of Kiribati, where waters can reach depths up to 1,500 meters. As of July 15, the AUV had run suc- cessful missions the previous night, col- lecting much more data that needed to be processed and plotted. Targets plot- ted by the AUV were to be ground- truthed with the ROV. The team reported the coral reef slope was "a lot more demanding than we knew or even imagined." Im mediately offshore the reef edge in the search area, the reef slope drops in a near vertical cliff hundreds of feet tall. Coral outcrop- pings on the steep slope tended to snare the ROV tether, forcing the pilot to backtrack to free the snare, the team re- ported. Further out and deeper, the slope moderates. Except for debris from the SS Norwich City shipwreck, no man-made objects were seen in two 60- foot search swaths from 21 meters down to 365 meters. Flat coral surfaces with right-angle corners resulted in many false alarms. Operations concluded at the end of July. The team will analyze data and im- agery, and reveal its results in August. Alvin Submersible's New Sphere Passes Pressure Tests The new titanium personnel sphere for the human-occupied submersible Alvin was successfully pressure tested, said the Woods Hole Ocean ographic Institution (WHOI), the vehicle's opera- tor, in June. The sphere, which holds a pilot and two scientists, is designed to descend to 6,500 meters, which is 2,000 meters deeper than the previous sphere. As the final step in the sphere's construction, the tests validate the sphere design and fabrication and ensure it meets the re- quirements of the American Bureau of Shipping and the U.S. Navy. The sphere will be integrated into the Alvin early next year. Over the next sev- eral months, WHOI engineers will re- assemble the submersible and should begin dock trials in November. Alvin is scheduled to begin certification sea tri- als in December. The testing took place at the North rop Grumman (Falls Church, Virginia) hy- drostatic test chamber in Annapolis. The Southwest Research Institute (San Anto- nio, Texas) managed the design and construction of the titanium sphere as a subcontractor to WHOI. During the four days of testing, gauges were affixed to the interior and exterior of the sphere to measure strain and "creep," the change in the metal from prolonged stress. The sphere was filled with water, placed in a pressurized test tank of water and tested to 8,000 meters—nearly 12,000 pounds per square inch. The new sphere is 3 inches thick, rather than 2 inches thick. The sphere's interior diameter is 4.6 inches wider than the previous sphere, increasing the interior volume from 144 to 171 cubic feet. The sphere's construction required more than 34,000 pounds of titanium. Two barrel-shaped titanium ingots were fabricated and then reshaped into two giant hemispheres, which were joined using a special welding technique. -Jack Fisher, President "Your search for ferrous metals begins with Fishers Proton Mags" Diver Mag 1 Diver Held Mag $8,995 Only $12,995 Proton 4 mag Metal Detector for Iron and Steel "Fishers Diver Mag 1 and boat towed Proton 4 magnetometers give the best cost/performance ratio of any mag on the market today. They are the ulti- mate detectors for iron and steel targets with a 1,500 foot detection range for large targets. An altimeter is available as well as boat tracking and PC display software." MC-1 Mini Camera $1,995 Cable Tracker with Signal Injector $13,495 CT-1 Pulse 8X Call for a free catalog or visit our web site: jwfishers.com ROVs Side Scans Metal Detector $2,095 Hand Held $19,995 www.sea-technology.com $19,995 Scan-650 Scanning sonar $6,995 1953 County St., E. Taunton, MA 02718 USA • (800)822-4744 (508)822-7330 • FAX: (508)880-8949 • email: jwfishers@aol.com • www.jwfishers.com AUGUST 2012 / st 65

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