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Marine Electronics

September 2013 Issue

Homer Pro Monitors Currents and Waves in Rio de Janeiro
Brazilian oceanographic consulting firm HidroMares (Santos, Brazil) has been using a Homer Pro underwater relocation system supplied by Sonardyne Brasil Ltd. (Rio das Ostras, Brazil) as part of a currents and waves monitoring survey in Sepetiba Bay, Rio de Janeiro, Brazil. Contracted by Odebrecht (Salvador, Brazil) as part of a shipyard and naval base construction project for the Brazilian Navy, HidroMares is using Homer Pro to mark the position of the wave and current data, and tide and temperature sensors deployed on the seabed to monitor environmental changes inside the bay as a result of the ongoing infrastructure development.

A Homer Pro system comprises a diver-held relocation device and marker transponders which are deployed at the target locations. For this project, the transponders were installed together with the sensor instruments in anti-trawl seabed frames deployed at four points inside the bay at depths ranging from 6 to 18 meters.

Each transponder has a unique address code, enabling it to be accurately marked and relocated. When a diver wishes to locate a sensor frame marked with a particular transponder, he selects the address on the handheld unit which then sends out an interrogation signal. If in acoustic range, the selected transponder will automatically respond. The direction and distance to the transponder is displayed on the diverís unit, allowing them to swim straight to it.

CORPI Surveys Klaipeda Harbor for Port Development
The Lithuanian Coastal Research and Planning Institute (CORPI) at Klaipeda University has recently completed the first ever 100 percent coverage survey of Klaipeda Harbor using Kongsberg GeoAcoustics (Great Yarmouth, England) GeoSwath Plus Compact. The multibeam mapping system was chosen to deliver high-resolution bathymetry with coverage up to 12 times the water depth, along with coregistered, georeferenced side scan data that can be used for seafloor imagery and classification in shallow-water environments.

This European Union-funded project was carried out during the implementation of the Sustainable Management of Contaminated Sediments (SMOCS) Project, developed under the framework of the Baltic Sea Region Programme 2007 to 2013.

The work focuses on the mapping of contaminated sediments in the modern port development area. Full-scale, shallow-water multibeam, side scan seafloor imagery and seismic mapping were carried out by CORPIís staff to gain a full understanding of the morphology and distribution of the seabed sediments.

This project has special significance as it provides new information for ongoing dredging work and for future harbor developments, which, relying on these new data, can now be developed right up to the maximum possible depths. For sustainable future development, this highly dynamic environment needs to be fully understood, with proper recognition of the seabed morphology and sedimentary patterns of superficial deposits essential.

CORPIís main scientific activity is interdisciplinary research for sustainable coastal zone management, which includes analysis and forecasting of the changes in the marine environment as well as development of the scientific knowledge necessary for the sustainable management of coastal resources. For this project, the Institute used the modern, multipurpose motor boat Emma from emma technologies GmbH (Kiel, Germany), specifically developed for shallow-water seafloor mapping. The boat has an ad-hoc moon pool designed to accommodate the wide-swath bathymetry system.

SAIC Buys MakaiLay, MakaiPlan for Oil, Gas Exploration
SAIC (McLean, Virginia) has purchased two Makai Ocean Engineering (Kailua, Hawaii) MakaiLay Seismic licenses and one MakaiPlan Pro Seismic license for use in their seismic oil and gas exploration projects. Delivery of the new software and training of operators was expected to be completed in early September.

MakaiPlan Pro Seismic is a 3D simulation tool to plan the installation and retrieval of ocean bottom cables in mid- and deep waters. The operator can quickly simulate an entire cable lay in advance and in his office at 25 to 50 times faster than real time. The simulations can be used to test the feasibility of the planned lays, make equipment selection, train cable engineers, pre-lay and post-lay analysis, and create a ship plan for installation. A detailed analysis and simulation is valuable to best understand and plan for dynamic cable situations that occur during speed changes, starts and stops, and hydrophone body deployments.

MakaiLay Seismic builds on the MakaiLay engine and includes additional tools specifically designed for the seismic industry to accurately install and retrieve ocean bottom cables with many in-line sensors or node arrays in mid- and deep waters. MakaiLay Seismic can run on laptops and assimilate information from SAICís collection of cable installation equipment, including acoustic Doppler current profiler (ADCP) and transponders attached to the cable, and then output vessel navigation and cable payout instructions for the operators.

Fugro Chance Completes Shallow 3D Acoustic Metrology
Fugro Chance Inc. (Lafayette, Louisiana) has provided 3D acoustic metrology on a large 91-centimeter- diameter spool piece, despite environmental and logistical challenges. The metrology was performed from a platform in Enlace Litoral Tabasco, Gulf of Mexico, at 25 meters depth.

Active lines from the platform created a noisy auditory environment and the shallow water depth provided additional challenges in the long baseline (LBL) acoustic operations. Once measurements were finalized, the spool piece was welded to the existing pipeline and then set back down on the seabed. With limited tolerance for such a large-diameter spool piece to fit into the riser brackets, the delivery of precise measurements was crucial.

This was one of the most shallow 3D acoustic metrology projects Fugro Chance has ever completed, and the spool piece was the largest in diameter acoustically measured, the company said. The work was completed within 23 hours.


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