Manager Ben S. Johnsen
High up in Helgeland, Norway, at the foot of steep mountains and armed with a wire crane and clamshell bucket to remove sediment from a waterway, a dredging contractor was looking to ensure efficient performance when dredging in a severe and challenging environment, where the sea was deep and dark due to a lack of sunlight. Dredging specialist Marine Solutions was included in the project and asked to ensure the optimum setup on behalf of the end-client.
The challenge was that, once the clamshell was submerged, without the help of any software it was as if the crane operator was working blind. However, with the 2D software options available on the market, the operator would still have had to work by sheer intuition and guesswork, unable to see the seabed, the clamshell, or where material already had been removed – not the most ideal of conditions, especially for this project which had a very short time from contract to completion.
Consequently, Marine Solutions decided to search the market for a dredging software solution which would provide a clear visualisation of the seabed, as well as how and where to position their wire crane and the submerged clamshell bucket with as high precision as possible. Additionally, they wanted something that could work efficiently with huge digital terrain models (DTMs) without creating waiting time during the operation due to lag or interruptions requiring redoes or further checks.
Live 3D digging using the wire crane with the clamshell bucket. The clamshell’s progress is instantly mapped. Side and angled views of the bucket are shown in the small windows while the 3D overview of the project area is shown in the main view.
They contacted EIVA and explained the challenge, describing their needs for visualisation and accuracy. Through a very close dialogue with Marine Solutions, EIVA succeeded in adopting its 3D dredging software, NaviSuite Uca to this particular project as well by developing a new wire crane setup with an integrated clamshell bucket to create a ready-to-use solution.
Software setup adapted specially for the wire crane solution
EIVA worked in conjunction with the Norwegian specialist to position suitable sensors that could help register the opening and closing of the clamshell as well as the payout of the cable for lifting and lowering. The location of the sensors was carefully discussed and it was determined that two cable counting sensors would deliver the best results. One monitoring the cable connected to the clamshell, the other monitoring the cable that controlled the opening and closing.
This solution included calculating the geometry of the whole wire crane setup with boom, cable drums and wires to have the exact bucket position displayed real time in the software.
Since the geometry of each wire crane is different, EIVA created a configuration tool, IODesigner, within NaviSuite Uca to aid with the interfacing of any wire crane, no matter how large or small.
Precise 3D visualisation with instant update of the DTM
The end-client’s sensors were interfaced and the setup was configured in IODesigner in NaviSuite Uca, followed by the development of features within the software to enable visualisation of the cutting profile at the seabed to better understand where the clamshell would land. This enabled the operator to carry out and follow the operation on a 3D display installed in the cabin. No matter where the crane was positioned, the cross profile would be visible on the seabed and the operator would know exactly where to place the clamshell bucket next throughout the operation.
It was also important to the end-client that it would be easy to import and use large DTM models to prepare the operation using a DTM and a design grade model. NaviSuite Uca already offered these functionalities, operating with a high-precision triangulated irregular network (TIN) volume target dredge model, thus enabling the end-client to run the entire operation with extremely large data sets consisting of millions of points without any memory errors or computer down-time for the operator during the project.
Even in the harsh and dark environment, it was now possible to see the clamshell after it broke the water surface. The ease-of-use of software enabled the operator to see the entire operation at a glance with customisable views, as well as the ability to generate reports in minutes instead of hours.
According to Marine Solutions, since the dredging assignment took place at a depth of 20 metres, without the 3D visualisation it would have been almost impossible to finish the operation in the time available. The 3D visualisation and instant update of the dredge surface enabled the contractor to double speed of the operation compared to the time previously estimated when considering other methods for the project.
By having the cutting profile displayed on the seabed followed by the subsequent update of the DTM as the clamshell bucket broke the surface, an instant 3D visualisation of the progress made was available. Hence, the contractor was able to save time and money as the operation became decidedly more effective: The improved dredging accuracy allowed for reduced barge movements and post-project MBE surveys by giving the project managers greater confidence that the seabed had met the design grade without missing any high points.
Marine Solutions said the NaviSuite Uca 3D software helped to optimise the entire operation significantly – and that they probably would not even have accepted this challenging task without the proper software solution.