UNDERWATER INSPECTION
When used in single-echo or echo-echo modes, the gauge employs the Cygnus- developed MSI™ (Measurement Stability Indicator) to confirm a stable thickness measurement by turning the thickness reading numbers from red to yellow. This ensures that Cygnus’ long established philosophy of providing accurate and reliable thickness readings is carried through to the new range of thickness gauges.
Another element incorporated within the gauge is A-scan, this helps the user to verify the true back wall reading in difficult measuring applications.
Versatile measuring modes While the multiple-echo mode is recommended as the first choice when carrying out inspections, single-echo and echo-echo modes have been incorporated for measuring metals
with extreme front face and back wall corrosion which is sometimes found on sea defences and harbour pilings. The single-echo mode is also useful for attenuative materials such as cast iron found in water and sewage outfall pipes - as well as plastics.
Data logging options Cygnus DIVE has its own inbuilt data logging mode which stores up to 5,000 measurements with A-scan graphs, each stable measurement is automatically logged without the diver having to press any buttons.
The gauge can also be supplied with CygLink software where measurements and A-scans can be transferred from the gauge to the software for later interrogation, uploaded into a spreadsheet and reported as a .pdf.
The CygLink software also allows measurements to be displayed on the surface and data logged topside via a RS-485 serial data link whilst the survey is being performed by the diver.
To find out more, visit:
www.cygnus-instruments.com
SAVANTE PERFORMS RISER INSPECTION WITH HYBRID 3D LASER SCANNER
Aberdeenshire-based Savante Subsea Lasers has completed the inspection of a production riser catenary using a new hybrid underwater 3D optical scanner.
The DLS or “dynamic laser series” of underwater laser scanners, combines laser and real-time photogrammetry technologies in a single measurement system to create models of assets in the underwater environment.
Dr. Grant Thomson, Savante Managing Founder, said:
“Whilst 3D subsea laser profiler technology currently offer the highest measurement performance in terms of sub-millimetric precision, speed, resolution and repeatability in the underwater environment; they can be inherently limited in terms of practicality. When capturing 3D models of a subsea asset, a laser profiler may require input
from additional sensors to compensate for changes in its attitude and position during the measurement process. The mass, direct cost of this additional sensor payload and it’s integration can be substantial, but can also preclude the cost benefits of small inspection-class ROV deployment.
Savante’s underwater hybrid optical scanner combines the benefits of our highest-precision and fastest 3D underwater laser profiler with the very real-time SLAM (self-localisation and mapping) capabilities of our machine- vision system.
In many close-inspection applications, our SLAM-coupled laser profiler eliminates the need for those external sensors. With these two technologies combined not only can we create a 3D model of an object in motion; such as a riser catenary, we can also plot exactly the location of the ROV during the entire survey process.
Above: Savante Performs Riser Inspection with Hybrid 3D Laser Scanner.
Critically we compensate for relative movement of the product; eliminating the need for docking solutions. This greatly reduces operational risk, complexity and cost.”
Savante said it will be releasing a research-grade version of the system in the next month and aims to bring the cost of underwater laser measurement down to support a wider marine environmental, archaeological and academic community.
May 2017 |
www.sosmagazine.biz | p39
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