Martijn Koppert, Barge Master We speak the same technical language

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1 MARIN s news magazine for the maritime industry April 2013 no. 108 Martijn Koppert, Barge Master We speak the same technical language Complex model tests on MOHO NORD Tension Leg Platform Investigating the challenges of the deep Minimising fatigue damage during FPSO transport

2 editorial colophon report is a news magazine of MARIN Haagsteeg 2, P.O.Box AA Wageningen, The Netherlands P F Printing 3,800 Editorial Board Bas Buchner, Timo Verwoest, Ellen te Winkel (e.te.winkel@marin.nl) Editorial consultant Helen Hill Design & Production Verheul Communicatie Alphen aan den Rijn, The Netherlands Cover Barge Master supply operation The editorial staff has made every attempt to ensure the accuracy of the contents. However, experience has shown that, despite the best intentions, occasional errors might have crept in. MARIN cannot, therefore, accept responsibility for these errors or their consequences. For remarks or questions, please contact Ellen te Winkel (e.te.winkel@marin.nl) For subscription to MARIN Report or cancellation, please visit Successful testing campaign for the Barge Master Martijn Koppert, creator and director of Barge Master, explains how the success of a test campaign at MARIN paved the way for the start of this pioneering product, which is already being warmly welcomed by the industry as a solution for safe, motion compensated offshore lifting. 9 Investigating the challenges of the deep New deepsea mining concepts under test in the Deep Water Offshore Basin. 10 Tests for one of the largest floating platforms in the world MARIN carries out a model test campaign for Samsung Heavy Industries for a semisubmersible, which is destined for the Ichthys Field, offshore Australia. 11 Efforts to improve the modelling of thrusters continue New thrusters built with a 7-degree tilted thruster axis. 12 MARIN goes with the wind Model tests for floating wind turbine concepts 13 Wind Load modelling JIP underway MARIN is conducting fundamental research into wind modelling, aiming to develop a generic, practical outcome for the industry. 14 Complex model tests on MOHO NORD Tension Leg Platform In an ambitious campaign the MOHO NORD TLP was extensively tested in the Offshore Basin. 16 Minimising fatigue damage during FPSO transport Using dedicated tools, MARIN can advise about how to minimise fatigue damage already in the design phase of an FPSO. 17 MARIN introduces two full tug simulators MARIN has upgraded two part task simulators into full tug simulators. And they are already proving a big success with clients. 18 Joint R&D in JIPs An update on the latest Joint Industry Projects 21 SHARES shows unique results The SHARES project on the understanding of thruster dynamics is showing unique results, both at full and model scale. 22 New Monitas Group successor of Monitas JIP Following the success of the Monitas JIP, which will complete this year, a new group is being created to provide Monitoring Advisory Systems for offshore floating structures in the future. 23 Obelics JIP successfully achieves goals as project concludes The Operability of Ballasting and Lifting Operations of Extreme Loads with Integrated hydrodynamics JIP is concluded after two years of intense cooperation. Dear Reader, An Offshore Special in MARIN s Report has a bit of a family photo album feel about it, allowing you to look back over the year with its highlights and meetings with family and friends. This year s special shows the large variety of projects and clients that MARIN has been working with. On the one side, we were involved in the largest semi-submersible in the world for the Ichthys project, and on the other, we were helping the new start-up company, Barge Master, with its innovative motion compensation system. It is this large variation in projects and the related challenges that stimulates MARIN s people. The Ichthys semi-submersible model for Samsung Heavy Industries was in fact, one of the most detailed that has ever been engineered and manufactured by MARIN. Testing the motion compensation of Barge Master was challenging in another way. MARIN developed a model scale version that mimicked the exact behaviour of the Barge Master s hydraulics and its controls. This model facilitated the careful validation and tuning of the Barge Master system. In this issue we interview Martijn Koppert, creator of the Barge Master. Report provides a good insight into recent developments in our industry. New deepsea mining concepts were recently under test in the Deep Water Offshore Basin. MARIN organised a demonstration model test to show the feasibility of two typical systems and to investigate their hydrodynamic challenges. Offshore wind also continues to be an important focus and MARIN is involved in several projects from scale model tests on floating wind turbines to wind load modelling. Our special wind set-up for these tests is very successful and we are delighted to be involved in these projects of the future. We hope to see you soon at OTC and Nor-Shipping, or of course, somewhere else in this challenging industry! Bas Buchner President 2 report report 3

3 news news Tidal Current Turbine JIP launches papers EEDI Verifiers course Software Seminar Houston October 8 MARIN and Airborne Marine are initiating the first Joint Industry Project on the structural and hydrodynamic design aspects of tidal current turbine blades, along with other participants. Based in the Netherlands, Airborne Marine is a constructor of composite turbine blades. Tidal and ocean currents are the subject of interest for green energy because of their predictability and consistency. The design of tidal turbine blades constitutes a major issue for the successful introduction of reliable and productive tidal energy. The objective of the JIP is to investigate the loads and operational efficiency of tidal turbine blades. MARIN plans to use its unique facilities such as the new Depressurised Wave Basin, in which environmental conditions and turbine-turbine interaction can be recreated, and dedicated cavitation and noise measurements can be undertaken. Further supported by CFD flow simulations, the JIP will deliver valuable information for the design of reliable turbine rotors. Participants are welcome to join. For more information please contact Gert-Jan Zondervan, g.j.d.zondervan@marin.nl MARIN offers a wide selection of papers and doctoral theses in the field of hydrodynamics on its website at The most recent publications include: New guidelines for speed power trials, level playing field established for IMO EEDI H. van den Boom, H. Huisman, F. Mennen, SWZ Maritime, 2013 URANS calculations for smooth circular cylinder flow in a wide range of Reynolds numbers: solution verification and validation Rosetti, G.F., Vaz, G. and Fujarra, A.L.C., Journal of Fluids Engineering, 2012 The MARIN systematic series fast displacement hulls Kapsenberg, G.K., 22nd Int. HISWA Symposium on Yacht Design and Yacht Construction, Amsterdam, 2012 MARIN is organising a new specialist course for EEDI Verifiers: Ship Propulsion, Model Tests & Speed/Power Trials. The course will be held in Wageningen, the Netherlands, June From January 1, all newly delivered ships or converted vessels have to have an Energy Efficiency Design Index (EEDI). The determination of the EEDI includes the model testing of the vessel, the design, construction and the delivery trials, where the speed/power characteristics are finally assessed. For each vessel an EEDI Verifier appointed by the flag state has to verify that the EEDI procedure is compliant with the IMO MEPC EEDI regulations. In these regulations special reference is made to the required procedures for the model tests and for the speed/power trials. This five-day specialist course will help make participants fully conversant with ship propulsion theory, design practice, resistance and propulsion model tests, extrapolation procedures and coefficients, as well as the conduct and analysis of speed/power trials within the EEDI framework. Besides the theoretical background during the course, practical instruction will be given at MARIN s After three successful software seminars in the Netherlands, MARIN is adding a Houston edition this year on October 8. This seminar brings together developers and users to share experiences and define future requirements. If you have used MARIN s software or are considering using it, we would like to meet you and hear your feedback and requirements. The seminar will focus on integrating model tests, simulations, training and monitoring in order to realise safe and economic ships and offshore structures. model test basins, as well as on board a vessel undergoing speed/power trials. Evaluation of model test results and the analysis and corrections of trial results will be practised. The course is based on ITTC procedures and those of the STA-group on sea trials. For more information and registration: Saskia van de Peppel on , courses@marin.nl or visit marin.nl/courses During the day we will share experiences in carrying out complex numerical studies, looking both at the software s use and hardware requirement. Several new, innovative projects will be presented to show the latest in maritime simulations. Expect presentations on hull design optimisation to minimise resistance. New scenario analysis tools will also be introduced, which ensure effective operations and voyage planning. More detailed information on venue, programme and registration at OTC May 6-9 MARIN will again attend OTC in Houston. Meet us at the Dutch Pavilion at Stand No to find out all about our offshore services. And join us for splashy drinks on Tuesday May 7, hrs. SAIL into a sustainable future MARIN is participating in the ambitious SAIL project, which aims to develop hybrid wind propelled vessels in order to reduce emissions and fuel consumption, ultimately to achieve zero emission freight sailing. Seventeen partners from seven North Sea countries, including ship operators and knowledge institutes, are taking part in the three-year project, which will run until June MARIN s voyage and scenario simulation tools will be used. These are of particular interest because the performance of hybrid, wind-based designs will depend strongly on the realised speed and power consumption that can be expected in real offshore wave, wind and current conditions on actual routes that could be sailed by the vessels under consideration. The project will look at the technical developments required, as well as the economic context, public-private partnerships, policy and legislation. SAIL is an Interreg IVB North Sea Region Project, which has a budget of 3.4 million. For more information see anymoor a user-friendly interface for mooring system analyses Mooring system analysis has just become more accessible and user-friendly thanks to recent developments. In the past MARIN has delivered several time domain calculation programs but the main focus has always been accurate modelling of the physics and being userfriendly often came second. However, the development of a single time domain code for different applications opened the door for generating a user-friendly Graphical User Interface (GUI) to run the analysis. The already proven programs TERMSIM and DYNFLOAT were used to build a new GUI that uses the anysim simulation program. This new program is called anymoor and can be used to define input, run the analysis with anysim and to review the results. Currently, the TERMSIM and DYNFLOAT functionality are available in anymoor but the modular setup means that future developments in the anysim Code can be added into the GUI. For more information contact Robert Heerink, r.heerink@marin.nl C&SI May MARIN will again be present at the Construction & Shipping Industry event held in Gorinchem, the Netherlands. Visit us to discuss the broad range of services we offer the inland shipping industry. Nor- Shipping June 4-7 There is a chance to meet us again at Nor-Shipping In Oslo. You are welcome in Hall C at Stand CO2-18, which is in the Maritime by Holland Pavilion of HME. 4 report report 5

4 Safe, motion compensated offshore lifting Successful testing campaign for the Barge Master Officially launched in December 2012, Barge Master is an innovative solution to the common problem of sea-induced motions during offshore installation work. Martijn Koppert, creator and director of Barge Master, explains how the success of a test campaign at MARIN paved the way for the start of this pioneering product, which is already being warmly welcomed by the industry as a solution for safe, motion compensated offshore lifting. Headquartered in Rotterdam, Barge Master develops and produces wave compensated platforms for the marine and offshore installation industry. The first Barge Master, the S700/C400 can carry a 400mt crane or, alternatively, compensate loads up to 700mt when used as a supply platform. The first Barge Master, BM-001, is now on the market for commercial use. Barge Master asked MARIN to prove the concept could work by carrying out both scale model tests and numerical modelling. Spending his whole career in marine services and marine construction, Mr Koppert was well aware of the problems of crane loads starting to swing when there is a swell. He drew on his engineering knowledge to formulate a possible answer to the problem. For some time, jack-up barges have been used offshore but these are a fixed and very expensive solution and difficult to mobilise. Around five years ago I asked, Why not solve the problem with hydraulics? This was the start of Barge Master and his efforts to compensate the motions of the vessel using hydraulics, whilst taking roll, pitch and heave into account. Martijn Koppert, creator and director of Barge Master Huge potential Barge Master teamed up with drive and control company Bosch Rexroth to explore opportunities. The first major issue to be addressed by the partners was to check whether the Barge Master would influence the behaviour of a barge. We wanted to make sure that it wouldn t exaggerate vessel motions and we needed to analyse whether the combination of a barge or a crane, plus the Barge Master, could result in a stable platform. And as well as determining the whole stability of the configuration, Barge Master wanted the tests at MARIN to show people that the concept worked from the scale model to convince the market and investors of its huge potential. Mr Koppert was already familiar with the work of MARIN because several former colleagues worked there, so it was a natural choice for the tests. MARIN developed a model scale version of the Barge Master, where the hydraulic system was modelled with electronic motors and an electronic control system. This system mimicked the exact behaviour of the Barge Master s hydraulics and its controls. The MARIN model facilitated the careful validation and fine-tuning of the Barge Master system. It was an enormous challenge, he admits. Barge Master had to hire the Shallow Water Basin for several days in February The scale model was tested with suspended loads in various wave periods and headings. Working with MARIN was very easy, he comments. We are very enthusiastic about MARIN s performance. Small project teams from each organisation worked closely together during development. We speak the same technical language and MARIN has the right spirit! This is also an interesting project for MARIN and the Classification Societies because it is a complete first. Everybody wanted to make it happen. Results better than expected Tests with the crane showed that the hook and the load were perfectly still and this was proven in real life during sea trials in the North Sea. The results were even better Supply operation 6 report report 7

5 platform mounted on a standard barge. An offshore supply scenario was staged in the concession zone of the future wind farm, Rentel, in the Belgian North Sea. During an earlier test in the Dutch North Sea, the motion compensated installation solution was tested involving a standard crawler crane mounted on the Barge Master, which in turn, was mounted on a standard North Sea barge. Tests were performed in a variety of sea-states and mooring setups. With the Barge Master switched on, the crane hook and load hung perfectly still. Mr Koppert says: Wind farms are normally built by jack-up barges whereby components are loaded on the jack-up and then sailed to the location. But this is restricted because they can only take one or two turbines at a time. The Barge Master means it is possible to avoid leaving the field and returning to port continually. Investigating the challenges of the deep New deepsea mining concepts were under test in MARIN s Deep Water Offshore Basin. Crane operation at North Sea than expected, with the hydraulic platform compensating wave percentages upward of 95%. Numerical models also showed that the system would be stable. The Barge Master can handle significant wave heights of up to 2 m. It is suitable as a motion compensation platform for any type of crane on flat top barges and vessels or for stabilising cargo during vessel to platform transfers. During the testing period the team also found that the original 2 m maximum stroke for the cylinders was not enough and this had to be changed to 2.5 m. Barge Master decided to compensate at three degrees of freedom: roll, pitch and heave. Even with enormous forces, it provides a very stable platform on the horizontal plane. We knew it was possible but now it was proven that we could compensate motions for enormous loads of up to 700mt. Additionally, MARIN and Barge Master jointly developed a numerical model, which can show the performance of the Barge Master on any type of vessel. We can run the program and predict the performance in any wave conditions. We can show potential customers the performance and workability and most crucially, can quantify this workability. Quantifying workability Once the tests were concluded, construction got underway and sea trials took place in the North Sea in Tests along with maritime contractor, GeoSea, were undertaken using both a crane configuration and also using the Barge Master as a supply platform. GeoSea provided a jack-up barge and all the maritime services. The North Sea tests encompassed an offshore supply operation involving GeoSea s jack-up barge, Goliath and the Barge Master Wind farms Barge Master is ideal for the offshore, salvage, oil & gas industries, as well as for decommissioning. It provides increased safety and workability during offshore lifting and supply operations. It is a flexible solution using standard barges, cranes and vessels and a low cost solution. Marine lifting operations up to 1,000mt can be performed safer, quicker and under more adverse sea conditions, he emphasises. Its flexibility is shown in that the 700mt Barge Master is easily mobilised because it is fully containerised in only 12, 40 ft containers. It can be placed on any vessel and deploy any crane - be scaled up and down. Barge Master is currently developing adapted versions to accommodate different uses. At the moment, a small mechanism using a cylinder for compensating roll, pitch and heave is being developed, suitable for a payload of 50mt and the company is also considering versions going up to 1,500mt. Certainly the newly launched solution is making its mark in the industry. Clearly, the Dutch government also has confidence as it has been endorsed by the Innovations Office Agentschap NL and the government had guaranteed loans for its development. For the new applications, Barge Master is happy to return to MARIN. For additional testing we look forward to working with the team again. It has been very interesting to work together with MARIN and see this pioneering product develop from a concept to reality. Olaf Waals o.waals@marin.nl Recent developments in the offshore deepsea mining sector have resulted in new concepts for deep and ultra-deep systems to recover natural resources from the sea bottom. At water depths ranging from 300 m up to 6000 m, valuable materials can be recovered. Last February MARIN organised a demonstration model test to show the feasibility of two typical systems and to investigate their hydrodynamic challenges. Natural resources can be found in the proximity of so-called black smokers, which are active subsea volcanic areas that produce sulphates and metallic nodules that settle down on the sea bottom. Various deepsea mining concepts are being developed to recover these resources at water depths ranging from 800 m to 3000 m and even deeper. Typical concepts involve a vertical riser system with mid-water pumps, gas lift systems or a deep water lifting arrangement to bring the material to the surface. A demonstration test was designed to show two systems in parallel deployed from one vessel. The vertical riser system was hung off from the centre of the vessel (including two mid-water pumps, modelled as 120t mass) and the deepsea lifting arrangement was located at the stern. A stock model was used at scale 1:80 to model the deepsea mining vessel and this was tested in the deep pit of the offshore basin at a water depth of 1530 m. From hydrodynamic research experience for the oil & gas industry in deep and ultra-deep water we know that there are challenges such as the dynamic response of floating systems in waves and current. Vortex induced vibrations and excitation of natural modes of the vertical transport system could occur. During the tests visual observations were made and accelerations in the vertical transport system were measured and these will be reported in a conference paper next year. 8 report report 9

6 Tests for one of the largest floating platforms in the world MARIN recently carried out a model test campaign for Samsung Heavy Industries for a semi-submersible, which will be used as the Central Processing Facility (CPF) in the Ichthys Field (INPEX/TOTAL), offshore Australia. Frederick Jaouen & Willemijn Pauw f.jaouen@marin.nl The CPF will be a permanently moored and column-stabilised production unit and the largest floating platform of this type in the world. The CPF model is one of the most detailed models that has ever been engineered and manufactured by MARIN. The modelling of the lower deck was especially detailed. This was necessary to model the structure-fluid interactions because they can have a significant influence on the measured slamming forces, air-gap and green water. MARIN assisted the client in the detailed design of the CPF by providing reliable measurements and advice. 0 deg. tilted nozzle deg. tilted nozzle deg. tilted nozzle The test campaign consisted of two phases. Seakeeping and towing tests were performed in MARIN s Seakeeping and Manoeuvring Basin to investigate the motions, resistance and towing stability during transportation to the site. In the Offshore Basin in-place tests were performed with all 28 mooring lines and 25 risers connected. The real water depth was modelled but the CPF was moored using a horizontal equivalent ( truncated ) mooring system because the anchor footprint was larger than the dimensions of the basin at the tested scale. These mooring tests were performed in combinations of extreme waves, current and wind. Detailed design In addition to mooring line loads and the CPF s offsets, important aspects of the tests were the air-gap and slamming forces on the lower deck. To investigate these, the highly accurate lower deck model was equipped with a large number of wave probes and slamming panels. The influence of the wave time-trace realisation on the slamming events was also assessed by testing many seeds. Furthermore, four cameras and one high-speed camera were used to correlate the measurements to the observations made in the basin. This challenging project was successfully completed and it confirmed that the combination of detailed modelling, accurate measurements and flow observation using video camera (including high-speed) is a great combination to help clients when they are working on the detailed design of a CPF. 7 deg. tilted axis, 5 deg. tilted nozzle 7 deg. tilted axis, 7 deg. tilted nozzle Model with mounted thrusters Efforts to improve the modelling of thrusters continue MARIN uses thrusters in many projects. For a typical model scale, around 1:50 to 1:60, relatively small thrusters are required. Thrusters for these models are available ranging from 50 mm to 80 mm nozzle diameters. Robert Heerink, r.heerink@marin.nl In the past these thrusters were always modelled with a horizontal shaft. By tilting the nozzle, the closest possible match was achieved between the client specifications and the modelled thruster for the basin tests. Due to the ever-evolving process in improving the models, new thrusters were built witha 7-degree tilted thruster shaft. Special gears were made for a reliable and durable thruster model and with these new thrusters it is still possible to mount nozzles with a slightly different angle. See figures for examples. The newly built thrusters give clients the ability to choose a more accurate representation of the thrusters used during model testing. 10 report report 11

7 Scale model tests for floating wind turbine concepts MARIN goes with the wind In a pioneering development, MARIN has conducted an extensive model test campaign for floating wind turbine concepts. This represents the first time such an extensive campaign has ever taken place. Erik-Jan de Ridder, e.d.ridder@marin.nl Tanker approaching structure in complex wind field Floating wind turbines are considered to be the next step in the development of offshore wind energy. In 2011, MARIN performed model tests for three different floating wind turbine concepts for the DeepCwind Consortium (USA), led by the University of Maine. For these unique model tests MARIN and the DeepCwind Consortium worked closely together to develop a new, high quality wind generation machine in the MARIN testing facility. Floating wind turbines facilitate wind energy generation in deeper areas with more wind and more space. However, selecting the most economical platform with minimised turbine motions is an important technical challenge. This is why DeepCwind chose to test a Spar, Tension Leg Platform and Semisubmersible at MARIN. The scaled-down model tests are an early part of the Maine Deepwater Offshore Wind Plan, which aims to have a commercial floating wind farm in the Gulf of Maine by the year 2030, generating 5,000MW of energy. A key point during the model tests was that wind and waves were presented simultaneously, allowing the study of the complex motions and loads of the rotating wind turbine on a moving platform in both wind and waves. To simulate the motions and loads correctly it is important that the thrust load generation by the wind turbine is simulated correctly in the basin. Due to Reynolds scale GustoMSC Tri-Floater with MARIN stock wind turbine model and active pitch control effects, the model tests showed that the wind turbine generated a lower thrust, and thus a lower loading on the floaters. A new scaling method for the model scale wind turbine was developed and this will improve future model testing. This method was then used to develop a new generic model scale wind turbine, which has been constructed at MARIN. Incorporating an active pitch control to test different control systems in the basin, this stock wind turbine is available for new projects, reducing the cost of model testing. Four new floating wind turbine projects have already taken this opportunity and tested their designs at MARIN. MARIN is conducting fundamental research into wind modelling, aiming to develop a generic, practical outcome for the industry. Koos Hoefakker c.m.hoefakker@marin.nl Wind Load modelling JIP underway The importance of correct wind modelling is increasing with larger, taller floating structures being developed. This is important for port and terminal design, as well as for the offshore industry. Traditionally, wind tunnel models are used but nowadays, CFD is advancing to complex, large domain problems, also enabling wind research. A comparison between CFD and wind tunnels, or between wind tunnels, results in significant differences. Therefore, the development of adequate guidelines for the reproducibility of wind tunnel tests and CFD calculations is necessary. This had led to the birth of the Wind Load JIP. The Technical University of Eindhoven, DNW, BMT and MARIN initiated the JIP, they would welcome new participants. Reliable wind loads Wind loads on single structures will be considered. Additionally, loads on structures in the 3D wake field are of interest. This JIP aims to define a standard for modelling the Atmospheric Boundary Layer (ABL) to determine the level of detail needed to model structures and to gain insight into scaling effects, as well as determining loads on structures in 3D wind fields. The JIP aims to better understand and predict complex wind loads on floating structures. The ABL is investigated for complex terrain, including a port or terminal with buildings, a bay surrounded by hilly terrain, rough seas or during offshore operations comprising multiple structures. CFD and wind tunnel tests are examined and a modelling standard for both methods will be developed, enabling a reliable prediction of 3D wind fields. The required level of detail of floating structures, scaling effects and overall accuracy of wind loads is investigated by systematically changing parameters in both wind tunnel and CFD models. The final challenge for the JIP is to translate the insight gained into a practical engineering tool. Currently, an approach is foreseen based on building blocks for different vessel subdivisions. Level of detail is prescribed by the developed guidelines. A 3D wind field, calculated or measured according to the above-mentioned standards, is applied, resulting in the loads on the structure. 12 report report 13

8 Complex model tests on MOHO NORD Tension Leg Platform hawsers connected, the TLP was kept in the zero position by two hold back lines and a Fluid Transfer Line. Model tests were conducted in wind, waves and current in a variety of setup configurations: with the semi-submersible alone, TLP alone, TLP + semi-submersible coupled and TLP + semi-submersible decoupled. During the test campaign the orientation of the TLP alone was changed once and the orientation of the coupled setup (TLP + semi- submersible) was changed twice, allowing for different basin current incident angles, in combination with a variety of wave directions. Complex setup This complex model test setup required thorough planning and preparation. The mooring lines of the semi-submersible, as well as the hold back lines of the TLP, had to be truncated in such a way that the stiffness is represented properly and the footprint of all anchor blocks fitted on the 10 m deep basin floor in all three coupled orientations. With the proper truncation at hand all anchor blocks were placed in the correct position at the beginning of the project making use of the moveable basin floor. With the anchor blocks in place divers could easily adjust any change of orientation. During these tests a total of 87 channels were measured. Video cameras were positioned above and underwater to capture the coupled motions of the TLP and semi-submersible. The combination of measured signals and video images gave a lot of important insight into the understanding of the complex hydrodynamics of the coupled test setup. correct mass/displacement ratio, which is important for the VIM response of TLPs. They have extremely low friction in the horizontal plane. This setup ensures a set of clean tests, where the total damping and flow patterns originate from the structure s hull alone. In addition, the tow heading of the model can be changed very quickly and efficiently. For the VIM tests an optimised scope was carried out for different headings and a range of reduced velocities. The two-body system proved to be particularly challenging Inplace tests, TLP and semi-submersible coupled as the coupled models had to be rotated in the basin for different headings and two different hawser systems. The Depressurised Wave Basin, measuring 240m x 18m x 8m, again proved to be extremely suitable for such complex tests. These tests show that VIM is particularly relevant for fatigue issues and that it remains an important phenomenon that should be taken into account during the design stage. In an ambitious campaign the MOHO NORD TLP was extensively tested in wind, waves and current. Arjen Koop & Jule Scharnke a.koop@marin.nl Model tests took place for the TLP alone, as well as with the TLP coupled to a semi-submersible. For both configurations, in-place wave tests and VIM tow tests were carried out. MARIN s capabilities and experience in complex model testing resulted in a very successful and interesting test campaign. In-place tests were performed in the Offshore Basin with its 30 m deepwater pit, which is necessary to be able to model the TLP with its tendons over the full water depth. The TLP was moored by 12 tendons and connected to a semi-submersible at a distance of 25 m by a hawser system. The semi-submersible will be used for tender assisted drilling in the first phase of the field development. The complex hawser system was modelled by four bi-linear springs linked together to represent the non-linear stiffness characteristics of the prototype hawser lines. The semi- submersible was installed in the Offshore Basin with a truncated and bundled mooring system, representing the mooring system stiffness of the full depth system. In the coupled setup with the VIM tests in Depressurised Wave Basin An extensive tow test campaign was carried out to investigate the VIM behaviour of the TLP alone and the TLP coupled to the semi-submersible by a hawser system. For the coupled system, tests were carried out with the two models inline with each other using two different hawser layouts and with the semi-submersible positioned at a sideways offset. Lastly, captive reference drag tests were performed for the TLP and semisubmersible. In the tow tests the TLP was mounted under an air-bearing system and vertical mooring springs. The air-bearings mean that the model can be tested at the VIM tests, TLP and semi-submersible coupled 14 report report 15

9 MARIN introduces two full tug simulators Minimising fatigue damage during FPSO transport Using in-house tools, MARIN provides advice on minimising fatigue damage during FPSO transport. Ingo Drummen, A significant contribution to fatigue damage occurs when an FPSO is transported from the yard to the oil field. On arrival, accumulated fatigue damage can be as high as 25%! Two analysis methods, based on spectral fatigue analysis, have been developed. Wave spectral information is combined with the proper trans fer function to obtain the structural response. A summation of the different sea states is done to come up with the fatigue damage. For the first, statistical approach, the sea state information is obtained directly from a scatter diagram. Although state-of-the-art and straightforward, it is not evident how to account for the joint occurrence of wind, sea, swell and current, for instance, or the reaction of the transport officer on large motions and accelerations. Therefore another, more practical method is being used. Route scenario simulations At MARIN software has been developed for performing route scenario simulations. A practical way around the limitations of the statistical approach is based on a deterministic, step-wise simulation of a given mission. The use of hind cast data as input for wind and waves solves the problem of accounting for the right coherence between wind and waves and the varying spectral characteristics of the waves. Route simulations also take typical human reactions such as heavy weather avoidance into account. By combining these simulations with structural information about the FPSO, an estimate of the fatigue damage can be achieved. Both methods rely on structural information. In the early design stage limited information is available but at the end, a detailed three dimensional finite element model can be used to derive the necessary structural data. Tools developed at MARIN are capable of using different levels of detail in the structural analysis. This makes them useful in the early design stages when little information is available and during the final stage of the design process. Using the proper transfer function both tools can be used to minimise fatigue damage accumulation during transportation. For instance, to determine the difference in fatigue damage when transporting in a towed configuration or on a heavy lift vessel. MARIN has upgraded two part task simulators into full tug simulators. Following their introduction, the simulators were successfully used in training and studies for amongst others, TOTAL, Port of Rotterdam, Meyer Werft and OLT Toscana. Dimitri van Heel d.v.heel@marin.nl For years MARIN s Nautical Centre has made extensive use of full mission bridge simulators for nautical studies and training and for many of these simulations tugs play an important role. Although it is possible to use computer (or autopilot) controlled tugs, it is preferable to have the tug masters themselves control the tugs. This brings a high degree of realism to simulations and also importantly, the vast experience of the tug masters provides valuable input. Previously, MARIN had often used part task simulators but it took the decision to upgrade these to make the training as realistic as possible. The new tug simulators are a great step forward. Instead of sitting in a room with a one-screen visual image, the tug captain now steps onboard a real vessel. With 270 degrees of projected visual scenery and a large TV screen for the view astern, the tug captain is provided with the same view as he has from his own tugboat. This includes a good view abeam, which is a great help in estimating the tug speed. More realistic To make it feel even more realistic, much attention was paid to the consoles and the simulators are equipped with professional helmsmen NorSap chairs. The newly developed hi-tech consoles, which have flexible controls, allow the tug stations to be converted from ASD tugs to a conventional or Voith Schneider configuration within minutes. The controls and read-outs are generic and self-explanatory, making them ideal to simulate different ship types. As well as tugs, they can also be used to simulate inland waterway vessels or coasters for example. The first feedback MARIN has received from the tug masters using the new stations was highly enthusiastic. As well as improving the experience of the tug masters, this upgrade makes dedicated tug training possible and MARIN can now improve the realism of other simulations as well. 16 report report 17

10 Joint R&D in JIPs The offshore industry works closely together to share knowledge, experience and costs. Here an update on the latest Joint Industry Projects. Participants are welcome to join! SplashMonster Splash Zone Lift Monitoring Templates, pipe heads, ROVs and other structures going through the splash zone are critical in offshore installation projects. The loading by complex, 3-D waves in the vicinity of the vessel and the dynamic response of the structure suspended from the moving crane tip are difficult to predict reliably. Observing strict safety criteria leads to significant downtime and at many offshore fields, Waiting on Weather is a major component of installation schedules and costs. Offloading Operations Full-scale monitoring of side-by-side offloading Offloading operations are successfully carried out around the world and are often studied in detail with numerical simulation tools and model tests but comparisons between ongoing operations and study work are limited. This makes it difficult to answer the question about how representative desktop and realtime bridge simulations are for the actual offloading operations. Even if the applied tools contain no errors and the experienced user got all the input right, are we actually calculating the right things? Wind-Jack Interaction of jack-up legs with the seabed For jack-up wind turbine installation vessels the loads on the legs and the jacking system during touch-down and lift-off are considered the most critical aspects in the operational performance of the vessels. The aim of the JIP, which is in its second year, is to understand and predict this interaction between jack-up legs and the seabed in order to better quantify the operational limits. As a first deliverable to the participants, MARIN s existing time domain hydrodynamic tool anysim has been extended with a simplified soil response model, which enables the seabed impact loads on the vessel during dynamic vessel motions to be calculated. In the coming year an advanced soil response model will be developed and verified by soil mechanic, as well as hydrodynamic model tests. Finally, an easy-to-use practical tool will be developed. Wind-Jack will run until Q Contact: Jorrit-Jan Serraris, j.w.serraris@marin.nl VIM Vortex-Induced Motions of offshore structures Floating Offshore structures such as production semisubmersibles, TLPs and Spars, can exhibit significant in-line and transverse motions under current conditions. Such motions are generally called Vortex-Induced Motions (VIM) and could have a strong impact on the fatigue life of mooring and riser systems. VIM phenomenon is characterised by complex interactions between the floater and the flow around the floater. At the moment model test programmes are the preferred method to predict the VIM behaviour of the vessel. However, this is only feasible when the final design of the floater is known. Therefore, tools and benchmark data are needed to assess the anticipated VIM behaviour at an early design stage to be able to reduce the VIM response of the floater. This JIP is aiming at a better understanding of the wave loading and response of complex structures passing the wave zone. To avoid scale effects, fullscale tests with large smart dummy structures will be conducted from an offshore vessel in limiting sea conditions. Both loads and motions will be measured in combination with the 3-D waves and currents. Results will be compared against the current DNV rules, the WINDOS building block software and present day CFD models such as COMFLOW and RANS. Aims of this three-year JIP, which turns SplashMonster into SplashMaster, and starting now, include: - A practical computational tool for loads on complex structures in the splash zone - Recommendations for rule development - Best Practice for Engineering & Workability assessment Contact: Henk van den Boom, h.v.d.boom@marin.nl The Offloading Operations JIP will help answer this question. This involves a comprehensive monitoring campaign on side-by-side offloading from the Sanha FSO. Combined with interviews from people involved in the operation, the project aims to provide feedback for the design and guidance into the operations. Results and findings of the monitoring campaign will be compared to real-time bridge simulations and fast time simulations. An increased understanding will help participants improve the uptime and safety of the operations, especially for new vessel types and sizes. Contact: Arjan Voogt, a.j.voogt@marin.nl The primary objective of the VIM JIP is to increase the physical insight into the VIM phenomenon so the design of a floater can be improved during the design phase. The JIP will focus on model testing methodologies and CFD studies. Specific consideration will be given to: - The effect of geometric design parameters and appendages on VIM - Characteristics of the flow field during VIM - Differences in (environmental) conditions between model tests, CFD results and field observations with respect to VIM behaviour - Influence of scale effects on VIM To start shortly, the three-year JIP will be conducted in close cooperation with oil companies, offshore design companies, operators and offshore contractors. Contact: Arjen Koop, a.koop@marin.nl 18 report report 19

11 Wifi Wave impacts on Fixed turbines With a growing number of offshore wind farms, more and more damage is being experienced due to steep or breaking waves. The Wave impacts on Fixed turbines (WiFi) JIP primarily aims to better understand the influence of steep and breaking waves on the foundation and secondary structures of offshore wind turbines and to avoid damage by better calculation requirements in Guidelines and Standards for the design of the foundations. Monopile and jacket type structures will be taken into consideration. Research will consist of numerical studies, model tests and full-scale measurements covering hydrodynamic and structural topics. The fifteen participants include research institutes, classification societies, contractors, engineering and utility companies. After the JIP s conclusion, the next step in foundation design and classification can be taken. WiFi will run until Q4 of Contact: Marcus Schiere, m.schiere@marin.nl SHARES shows unique results Instrumented 5 MW thruster ready to re-enter service HELIOS Safe helicopter operations for offshore ships Helicopter operations are essential for offshore operations but equipment and procedures have basically remained unchanged for decades. Helicopter transport is considered amongst the higher risks to offshore workers and strict landing deck motion limits are enforced to maintain safe operations. Even in mild sea states, vessels often have to leave station for crew changes in port, which leads to high rates of downtime. Technology to improve safety and extend workability is available but is not certified for use in civil aviation. The Helios project set out to identify these new approaches, investigate and demonstrate their merits and work out how they can be practically introduced and integrated into the regulations for offshore flying operations. Initiated by MARIN and Dutch Aerospace Laboratory NLR, the project is carried out in a consortium, which includes oil companies, helicopter operators, aircraft and systems manufacturers, government/ regulatory authorities and technology institutes. The first phase completed in December 2012 and Phase II will run through to 2014 and will concentrate on quiescent period ship motion predictions, helmet mounted displays for assisted approach and landing, landing nets and deck lock systems for increased aircraft stability on deck. Contact: Jos Koning, j.koning@marin.nl Underway for a year, the SHARES project on the understanding of thruster dynamics is showing unique results, both at full and model scale. Johan de Jong j.h.de.jong@marin.nl Led by Allseas, 14 participants, including equipment manufacturers, are taking part in this interesting project that examines the dynamic loading and responses of thrusters. The project was initiated following the unexplained behaviour of gears and bearings within thrusters. The latter are summarised in a first JIP report based on the incident databases of the three participating class societies. One of the main objectives of SHARES is to identify what amplitude peak loads can really occur and under what conditions, when compared to design assumptions. To this end, Allseas agreed to instrument one of the 10, 5MW thrusters of Solitaire the world s largest pipe laying vessel. The 60-tonne thruster was extracted and disassembled during a docking in Italy and fitted with sensors by Allseas, Wärtsilä and MARIN to capture gear and bearing dynamics, drive shaft loads, the overall thrust and steering torque. Long-term monitoring under service conditions started in November 2012 and will continue for a year. In April, off design conditions such as crash stops, high-speed zig-zag tests and thruster interactions were evaluated during transit to Australia. An extensive model test program is being conducted alongside full-scale measurements to investigate specific dynamic phenomena. Two mechanical azimuthing thrusters have been selected for studying loads a pulling thruster with open propellers and a pushing thruster with a ducted propeller. Interaction tests with a second thruster are being carried out in open water conditions for all advance speed and steering angles. At ventilation condition, tests are planned with different immersion levels in waves - with and without cavitation - in MARIN s Depressurised Wave Basin. In order to determine the static and dynamic loads on these thrusters, high accuracy sensors have been developed. A 6-component shaft sensor has been instrumented to measure dynamic loads up to 500Hz on a key blade, duct and on the total unit. If you would like to share in this journey of discovery, the SHARES JIP is still open to new participants so please get in touch. 20 report report 21

12 New Monitas Group successor of Monitas JIP OBELICS JIP successfully achieves goals Following the success of the Monitas Joint Industry Project, which will complete this year, the Monitas Group is being created to continue providing services related to Monitoring Advisory Systems for offshore floating structures. Pieter Aalberts, OBELICS, the Joint Industry Project on Operability of Ballasting and lifting operations of Extreme Loads with Integrated hydro dynamics, was just rounded off after two years of intense cooperation. Ron Schoon & Eelco Frickel, Within the Monitas JIP, an Advisory Hull Mo nitoring System (AHMS) has been developed and successfully implemented for testing two FPSOs. And during the project, contract awards were received for the delivery of two more systems, showing that the system is already being recognised by the industry. The AHMS is an advanced hull monitoring system, which helps with the approval process of possible field lifetime extension and for the assessment of fatigue loading for relocation purposes. It explains reasons for potential deviation of the actual lifetime consumption from design predictions and translates the monitoring data into operational guidance and advice in an easily understandable format. The AHMS software has been developed in cooperation with Amarcon and WaveForce Technology and can easily be tailor-made for any FPSO. Starting in 2006, the Monitas JIP is supported by 16 participants, including the major oil companies and Classification Societies. Within the JIP, the system was installed and successfully validated for both the Glas Dowr FPSO (Bluewater Energy Services) and the USAN FPSO (TOTAL). In order to continue to provide Monitas related services to the industry, the Monitas Group will be initiated this year. The group is aiming to further develop the added value of advisory monitoring systems for integrity management by the correlation of measurements and by exchanging experiences, in addition to providing software updates, support and training. Activities may include analyses of the tool accuracy factors obtained from different floaters and further development of the AHMS software with, for example, the backward prediction module for existing floaters. New participants are welcome to join. Participants of the JIP comprised BigLift Shipping, Boskalis SMIT Engineering, Heerema Marine Contractors, Hydrographic and Marine Consultants, Jumbo Shipping, MARIN, Seaway Heavy Lifting, Scaldis, Statoil and Tree-C. The main objective of OBELICS was to develop and validate a new methodology for ballast and lift operations of extreme loads, incorporating all the relevant dynamics of this offshore operation. MARIN has developed the lift and ballast technology as part of its time domain simulation extendable Modelling Framework (XMF). The developed ballasting and lifting models are incorporated in the existing Mermaid manoeuvring simulator technology and extended with general Graphical User Interfaces to operate and observe ballast systems, cranes and winches. Scenarios for a float over operation, topside installation, buoy installation and the upending of a jacket were used as relevant reference cases for validation. Workshop on Full Mission Bridge First, simulations of these scenarios were carried out on an engineering tool and the ballasting and lifting functionality was verified by several JIP participants. Hereafter, the validation of the simulator was conducted together with the participants on MARIN s Full Mission Bridge. For the three-day validation workshop the bridge was extended with separate positions for the required ballast, crane, winch operator or superintendent. Multifunctional tool Now that the project is finished a unique combination of an engineering and operation simulator has become available. The operation simulator particularly, is a unique multifunctional tool that can be used for verification of the results of the engineering phase. This approach closes the gap between engineering and operations. Furthermore, a contribution of the operators can be assessed individually or as a team for a specific offshore operation. Results of the verification of the ballasting and lifting models and the discussions during the workshop will be included in a final report and used for future improvements. And because the JIP results are so promising there are good grounds for a follow-up program and the introduction of a special OBELICS simulator. 22 report report 23

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