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News and ongoing Projects |
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 2012 - Noise reduction during installation of wind turbines
According to legislation from the EU, sound emissions from the installation of windmills at sea must be reduced so the threat to marine mammals is minimised. Until now, no efforts have been made to reduce the water borne noise from driving monopiles into the seabed. With a new and innovative technology, it is possible to reduce the noise by up to 25 dB in a radius of 750 m. The technology is based on a cofferdam (patent pending), which complies with the recommended requirements of maximum: 160 dB SEL and 190 dB Peak for underwater pile driving noise levels. So far, Germany is the only country to have ratified the legislation, but the remaining EU countries are expected to follow Germany’s example.
The technology is developed by Lo-Noise, founded in cooperation between Kurt Thomsen, creator and founder of A2SEA (world leader in installation of offshore wind turbines), and OSK-ShipTech A/S (consulting naval architects with extensive experience in offshore wind projects).
The visionary thinking enables an installation process almost without delay as well as ensuring that the costs do not increase significantly by using the cofferdam from Lo-Noise. In Europe, the preferred foundation for offshore wind turbines is monopiles, which could result in an industrial adventure for Lo-Noise and their new noise reduction technology.
From the 15th to the 20th of December, the cofferdam was tested in the bay of Aarhus, Denmark with very positive results. The cofferdam is the only technology that lowers the noise level by 25 dB and meets the requirements of the EU legislation. The cofferdam test was performed together with the following companies: Grundfos, Trelleborg, NICON Industries A/S, DBB, Rambøll and OSK-ShipTech.
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2011 - Article in Mercator
An article from OSK-ShipTech explaining the power of CFD when optimising or designing a ship.
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 2011 - OSK hull design for the second time
The delivery of Dalby Esk, a catamaran with unique hull form, cements the excellent hull developed by OSK-ShipTech. The hulls are symmetrical with a very slender forebody that cuts the water and with a constant change in deadrise throughout aft to generate lift on the entire hull. Special focus was on the position of the sprayrails in order to optimise the lift and thus the running trim and effective power.
Originally, OSK-ShipTech A/S was commissioned by Alnmaritec to perform reference resistance calculations by use of CFD on a catamaran delivered to DONG Energy. The original hull form was tested in a towing tank and the resistance came out significantly higher than expected. OSK-Shiptech was asked to verify the result by conducting a “blind” CFD calculation of the hull lines.
OSK-ShipTech developed new hull lines and conducted CFD calculations to evaluate the resistance of the new hull form. The new hull form reduced resistance by 23 %.
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 2011 - The homecoming of Þór (Thor)
5 years after the contract was signed, the Iceland Coast Guard has finally brought its ship home from the Asmar Shipyard in Chile. The construction period has been turbulent. The almost completed vessel was in the drydock in Chile when the area was hit by a large earthquake followed by a tsunami in February 2010. The vessel subsequently underwent a major overhaul, and the delivery was finally accomplished in September 2011.
The ship is a Multifunctional Coast Guard vessel with capabilities within law enforcement, fishery patrol and resource management inside the Icelandic Exclusive Economic Zone, search and rescue (SAR), transport of rescue teams, vehicles and equipment for SAR, On-scene Command and Coordination (OSC) in large rescue situations and humanitarian aid operations. In addition, the vessel is able to participate in oil retrieval as part of the fight against marine pollution, fire fighting (Fi-Fi), and helicopter in-flight refuelling (HIFR) and is capable of towing up to 115 t bollard pull. Furthermore, the vessel is equipped with multi beam sonar.
OSK-ShipTech was the Iceland Coast Guard’s representative in connection with the preparation of tender documentation, establishment of the evaluation criteria, and throughout the tender process. In addition, OSK-ShipTech was responsible for shipyard evaluation and contract negotiations. Subsequently, OSK-ShipTech undertook design and plan approval from our Copenhagen office and provided a total inspection package at the shipyard in Chile. In short, our job was overall project management. |
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 2011 - Double up on CFD capabilities
We believe in the positive tendency in the market towards using Computational Fluid Dynamics (CFD) in design and optimisation of ships, and we are confident that the trend will continue in the future. Therefore, we have doubled our cluster capacity within CFD and now hold 6 STAR CCM+ licenses. That brings our total node inventory up to 100 and helps OSK-ShipTech to ensure a brilliant standard within CFD. Furthermore, it enables us to perform more advanced CFD calculations. Besides the new nodes and licences the investment also includes two new High Performance Computing servers.
With this investment, OSK-ShipTech stands ready to meet the future demands from the continuously growing number of customer that seek trustworthy and accurate CFD calculations implemented on their ship design.
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 2011 - Transportation of Siemens Wind Turbines
Siemens Wind Power has contracted Aarsleff / Bilfinger Berger Joint Venture (ABJV) to transport wind turbine generator sets from Esbjerg to the London Array wind farm.
OSK-Offshore was commissioned by ABJV to perform sea fastening design in order to make sure that the components were safely secured during transportation.
To that end, OSK-Offshore designed suitable fastening structures for towers and nacelles as well as wing racks and support structures and sea fastening for these. To rule out the risk of broken wings if wing immersions occur, a motion analysis by means of sea keeping calculations was conducted. The motion analysis was performed to document that the wings will not be immersed at the selected wind and weather criteria.
Deck arrangement and stability
The deck arrangement during transportation of wind turbine generators is crucial for stability, safety and sea fastenings, and for the barge in question, OSK-Offshore made a detailed deck layout for all wind turbine components on each barge. The layout included FEM calculations for tower and nacelle foundations as well as a check of the internal structure of the barge.
The intact stability was calculated for each relevant loading condition.
The design delivered by OSK-Offshore is suitable for the barges owned by ABJV as well as for the Heavy Deck Cargo barge chartered for the transportation.
OSK-Offshore has previously delivered a similar design to A2SEA, where Siemens wind turbines were to be transported to the Sheringham Shoal wind farm.
Following this delivery Siemens Wind Power has repeatedly expressed their satisfaction with the design; ”Siemens Wind Power were very happy with the design and have again re-confirmed that the systems work flawlessly.” - Jesper Møller, Specialist Offshore Installation, Siemens Wind Power. |
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