Sea Technology

JUN 2017

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

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16 st / June 2017 www.sea-technology.com tially replacing its batteries underwater. This procedure can be carried out without powering off the device. The brightness of the 12-in.-wide screen is ad- justable and enables div- ers to view the camera's images (acoustic or video), messages sent, charts (in which divers can display their route) and gradiom- eter measurements. In tur- bid water, divers can use the screen to extend their visibility. By using the vid- eo function, they can see up to 12 m on the screen, and the sonar camera can enable them to acquire vis- ibility for distances up to 150 m. Feedback: Time-Saving Before bringing SonaD- ive to market, RTsys suc- cessfully tested its capaci- ties at depths up to 70 m in Lake Geneva in December 2014. In March 2016, the first SonaDives were de- livered to the French Navy, for testing by bomb disposal divers, who found the SonaDive easy to use, thanks to its user-friendly control panel with joystick and backlit keyboard and its neu- tral buoyancy. The French Navy has since or- dered more devices for delivery at the beginning of 2017. On the civilian side, Creocean of La Ro- chelle, France, an environment and ocean- ography consultancy firm, carried out several projects monitoring various Posidonia mead- ows in the Mediterranean Sea using SonaD- ive (which is available for rent). In April 2016, during the first observation session using SonaDive off the coast of Bormes-les-Mimosas, users were very satisfied with the quality of the video tool. By the sec- ond outing, divers were able to use all of the handheld so- nar's functions. This project was carried out in turbid water, and the benefits of using SonaDive were apparent with the image quality, which can be modified by users using simple settings adjustments. The difficulty in this turbid environ- ment was to find previously installed markers, half of which could not be located using the naked eye. All markers were located using the SonaDive and its sonar camera, making satisfactory monitoring of the ecosystem possible. Creocean confirmed interest in the tool by planning numerous opera- tions that will use SonaDive throughout 2017. In these military and civilian applications, the SonaDive reduced dive time thanks to more detailed operation plan- ning before dives, with programming on land of the coor- dinates of the points of interest for divers. Preliminary mark up, performed by a boat equipped with a GPS and involving frequency sonar enables div- ers to go from a frequency of 900 kHz for medium range (up to 100 m) observation to a frequency of 2.25 MHz for very-close-range observa- tion (up to 10 m). A high-resolution video camera completes the ob- servation system, making it entirely adaptable to the marine environment, for example, for detailed moni- toring of aquatic plant life, coral reefs and other diffi- cult to reach coastal areas. An optional gradiometer can be added to the device to detect buried metal objects, such as underwater cables, mines or boat anchors. A wet-mate connector, spe- cially designed for underwa- ter applications, can be used to activate the gradiometer when underwater during operations. When it comes to soft- ware, RTsys is conscious of the impor- tance of displaying data in a format that is sufficiently standard so it can be read by the most wide- ly used software. Data col- lected by SonaDive can be exported in a format compat- ible with HYPACK process- ing software in order to make user interpretation easier. For example, the software can combine data obtained by the device from succes- sive tours of the same area, following the same circuit, to create a chart of the area being studied. Unlike a circuit indicated by markers, the SonaDive's programmed operation circuits vary greatly. They may con- sist simply of charting a course and going by a number of determined points (aligned or unaligned), or scanning an area with the diver going back and forth using the sonar device. The software is therefore able to readjust all of the information, even if the measurements were taken when moving in the opposite direction. The diver receives infor- mation directly from the area covered by the sonar, which means they can go back and scan areas that they did not cover initially and cover the zone in an optimal way. Basic Specs On land, the device weighs 20 kg; in water, it has neutral buoyancy, which can be adapted to the surroundings: ma- rine, fresh, brackish or saltwater. SonaDive has a battery life of more than 6 hours, which can be prolonged by sequen- (Top and Bottom) Navigation information, map, SMS and video or sonar view can be displayed on the 12-in. screen. A joystick, waterproof backlit keyboard and neutral buoyancy make SonaDive easy to use underwater. (Image and Photo Credit: RTsys)

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