Home | Contact ST  
Follow ST

Marine Electronics


April 2011 Issue

Unconventional Salvage for Ship Washed Ashore by 2010 Tsunami
The RV Cabo de Hornos was set for launch on February 27, 2010, from a shipyard in the Talcahuano Naval Base (Talcahuano, Chile) when one of the largest earthquakes ever recorded hit the central region of Chile, causing a premature launch as the vessel slid into the sea. After several minutes of drifting, a tsunami washed the vessel onto land on the opposite side of the shipyard.

Mammoet (Schiedam, The Netherlands), an American Salvage Association (ASA) member company, successfully refloated the vessel in January and delivered the boat back to its owners in Talcahuano.

Doing this required an unconventional salvage solution based on a proposition to drive the vessel onto a flattop deck barge with self-propelled modular trailers (SPMTs). The barge would be completely submerged in dry-dock and the vessel would be floated off. In total, 31 containers with heavy transport equipment were mobilized, as well as a 300-foot barge.

On January 26, the Cabo de Hornos was lifted with the SPMTs, after which it was transported to the dry dock wall. On January 27, the vessel was driven onto the barge moored in the dry dock.

Two days later, the Cabo de Hornos was floated off the barge and redelivered to the owners without incurring additional damage, ASA said. For more information, visit www.americansalvage.org.

JW Fishers Instruments Detect Debris Before Dredging Project
The RG Tanna Wharf Expansion Project for the Central Queensland Port is one of Autralia's largest current capital improvement projects. But before workers can begin extending its pier, widening berths and creating a new jetty approach, they needed to clear the area of underwater debris.

The Central Queensland Port Authority turned to Realf's Diving and Salvage (Gladstone, Australia) to survey the area and remove underwater debris before dredging operations. Using a JW Fish?ers (East Taunton, Massachusetts) SSS-100K/600K dual-frequency side scan sonar and a Pulse 12 boat-towed metal detector, Realf's team was able to locate and remove a considerable amount of underwater debris on the seabed, including some large metal objects that could have damaged dredges, JW Fishers said.

For more information, visit www.realfsdiving.com.au.

Laser Scanning Helps Company Prototype Fiberglass Boat
GKS Global Services (Plymouth, Michigan) recently helped a Minnesota company that builds small electrically powered watercraft create a 3D electronic model of a small fiberglass boat that had been designed and prototyped by hand.

As the company was preparing to scale up production, suppliers began requesting computer-aided design (CAD) data of the deck and hull so they could precisely make and fit ancillary parts for it. The company turned to GKS. To facilitate tweaks and updates to the handmade design, the company decided it needed a parametric model that could be revised and edited. GKS said the editable parametric CAD model would allow engineers to create uniform wall thicknesses and perform tests on the design to ensure its quality and functionality.

The boat company decided that only the outward-facing side of the deck and hull needed to be captured, so the parts were bolted together and scanned as an assembly.

GKS engineers scanned the fiberglass craft using the Laser Design FA system with a 10-inch Platinum FaroArm and an SLP-2000 line laser probe. The setup and scanning of the prototype took between three and four hours. After the scanning was complete, the raw data was processed and refined with Geomagic Studio. The processed data was then modeled into a symmetrical parametric CAD model in SolidWorks.

The next step in the development process will be to analyze the design in CAD and make digital prototypes to try out various improvement. For more information, visit www.laserdesign.com.

Longest Multisensor AUV Pipeline Inspection Completed
Kongsberg Maritime (Kongsberg, Norway) said it completed in February the world's longest multisensor autonomous underwater vehicle (AUV) pipeline survey using its HUGIN 1000 AUV, inspecting about 30 kilometers of subsea pipeline in an eight-hour, two-pass mission.

The pipeline inspection took place February 9 to 11 in the Hjelte fjord near Bergen, Norway, and was operated from the Royal Norwegian Navy vessel HNoMS Maloy.

The subjects of the inspection were two subsea pipelines going to the oil refinery at Mongstad, Norway. The HUGIN 1000 AUV was equipped with Kongs?berg imaging equipment, including a HISAS 1030 synthetic aperture sonar, an EM 3002 multibeam echo?sounder and an optical camera with LED lighting.

In the first pass, side scan data from the HISAS 1030 sonar were used to detect and track the pipelines in real time, using special software for pipeline detection and tracking extracted pipe-like features in the sonar images. The software, PipeTracker, which was developed in a collaborative effort with the Norwe?gian Defence Research Establishment in a project funded by the Norwegian Research Council, runs as a plug-in module in the standard HUGIN payload system. The HUGIN 1000 control system then uses the identified pipeline tracks to position the vehicle at an optimal range for HISAS imaging.

During the second pass, the AUV followed the pipeline tracks identified in the first pass at low altitude and inspected the pipelines using the EM 3002 multibeam and the optical camera.

After the mission, the recorded HISAS 1030 data was post-processed into high-resolution (four-by-four centimeter) sonar images and bathymetry maps of the pipeline. Together with the optical images and the multibeam data recorded in the second pass, this gave a detailed view of the pipeline surroundings and the pipeline itself. The complete procedure was repeated the next day over the second pipeline in a new eight-hour, two-pass mission.

Both pipelines were surveyed at a speed of four knots and at an altitude between four and 25 meters, depending on the sensor in use. Water depth was between 180 and 560 meters. For more information, visit www.km.kongsberg.com.


-back to top-

Sea Technology is read worldwide in more than 110 countries by management, engineers, scientists and technical personnel working in industry, government and educational research institutions. Readers are involved with oceanographic research, fisheries management, offshore oil and gas exploration and production, undersea defense including antisubmarine warfare, ocean mining and commercial diving.