Sea Technology

SEP 2012

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

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Eh and temperature anomalies a few tens of meters above the seabed and had an approximately 100-meter-diameter circular region of almost zero magnetic intensity over the same part of the seafloor. The shallower site on the flank of Mount Dent had scattered Eh signals and weak temperature anomalies but little or no magnetic anomalies. After locating each of the two different sources of hydro- (Top) HyBIS, equipped with grab module and carrying an ultrashort baseline bea- con and high-definition camera, being de- ployed from the RRS James Cook during the Cayman expedition. (Right) A HyBIS high-definition image of one of the active hydrothermal chimneys at the 5,000-meter-deep Beeb vent site. The pale gray material at the top left side of the chimney is a swarm of a hydrothermal vent shrimp species, Rimicaris hybisae, discov- ered during the Cayman expedition. echosounder for seafloor mapping and imaging, a three-component magnetom- eter, and a suite of optical and chemical sensors, including an Eh sensor to detect the source of hydrothermal venting. The AS6K missions, each of which covered several square kilometers, found evidence for near-bottom hydro- thermal activity at the two sites. The deepest one had strong thermal venting to within a few hundred meters, the third and most crucial phase of the exploration began with visual observations and sampling. During its 2009 expedition, the U.S. team from Woods Hole had deployed the ultradeep diving hybrid ROV Nereus but failed to locate any hydro- thermal vents on the floor of the MCSC. With this in mind, a differ- ent approach was adopted to meet the challenge. A traditional type of ROV would, at these depths, need expensive floatation, be heavy and cumbersome, and require a large operating team. Instead, the Na- tional Oceanography Centre team developed a smaller, lighter, mod- ular and versatile system, HyBIS. HyBIS ROV The HyBIS concept was devel- oped to survey and interact with the deep-ocean floor without recourse to expensive and complex work- class ROV technology. Developed in collaboration with Hydro-Lek Ltd. (Finchampstead, England), HyBIS is a 6,000-meter-rated, fully modular, electrohydraulic ROV comprising a command-and-pow- er unit fitted with three high-defi- nition and secure-digital cameras; 1 kilowatt of lighting; a pan and tilt bar; a sensor suite including a sec- tor-scanning sonar, an acoustic navigation beacon, hydrau- lic pumps, electric thrusters and fiber-optic telemetry; and a universal hydraulic and mechanical docking interface. The 16 st / SEPTEMBER 2012 www.sea-technology.com

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