STEVSHARK®REX: HOLDING POWER IN THE MOST EXTREME CONDITIONS

Kelly Antonis | Barry Stolp 26 April 2017

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Redefining boundaries

Vryhof Anchors, world leaders in the market for innovative and customer-focused anchoring and mooring solutions, will be launching a revolutionary new anchor around the OTC 2017 event in Houston. Following two years of development and testing, the Dutch company is proud to announce the launch of its STEVSHARK®REX. Better, smarter and stronger, STEVSHARK®REX delivers holding power in extreme conditions unmatched by any other anchor. As a result, the application boundaries of drag-embedded anchors can now be expanded to the most remote and challenging territories on earth. Super-strong soils no longer represent an obstacle, thereby opening up economic opportunities for operators to develop new energy resources across a much larger area worldwide.


Evan Zimmermann, Vice President & CTO at Vryhof, is convinced that the new STEVSHARK®REX will be a game changer in creating a much more cost-effective solution for anchoring on substrates including calcarenite, a carbonite rock commonly found on Australia’s Northwestern Shelf.

“The STEVSHARK®REX is probably the most anticipated development in the mooring industry over the last decade. I truly believe that the launch of this anchor will create huge excitement and that the market will view the STEVSHARK®REX as a game changer. Right now, the largest initial market for the new anchor is the oil and gas sector. The drilling community is set to embrace the tool since it offers them a very cost-effective solution in a very tight market. The STEVSHARK®REX will offer a cost-effective drag-embedded anchor system in place of driven, bored and grouted piles which are much more expensive and require long lead times for design, fabrication and installation. There is no other comparable cost-saving and efficient mooring solution available on the market, right now. This anchor will enable operators to develop fields and renewable projects which, until now, could not conventionally be economically developed. With its greater flexibility in vessel and timing options, unlike other anchors on the market, the STEVSHARK®REX can effectively penetrate even the hardest sea floors and perform predictably.”

Discover STEVSHARK®REX – Holding power in the most extreme conditions:

Innovative people

Senol Ozmutlu, Projects Director at Vryhof Anchors, explained the motivation behind developing the STEVSHARK®REX. “We are not your average hardware shop. At Vryhof Anchors, we offer anchoring knowledge based on long practical experience, as well as knowledge of the geotechnics, experimental research, modelling and testing. For almost half a century, we have continuously set benchmarks in offshore anchoring technology serving oil and gas, renewable energy and civil and construction sectors, among others. We continue to prove that innovation is more than just a buzzword. At the same time, we are able to strengthen our global leading position in the mooring world, while anticipating the needs of our customers with whom we work closely in order to understand their wishes and future mooring needs. We constantly strive to deliver improvements for the offshore industry, be it oil, gas or renewable energy, as well as the dredging industry by integrating groundbreaking technologies. Our latest offering is intended for anchoring under challenging and hard ground conditions, anywhere in the world. We are always focused on making life easier for our customers, and contributing to their success. It is our conviction that the best way of doing this is to offer state-of-the-art, innovative technology and tailored solutions. For that reason, Vryhof Anchors operates its own R&D Centre and invests well above the industry average on innovation. Thanks to our pioneering attitude we have already developed many cutting-edge mooring solutions for all kinds of floating structures, making everyday life more effective and more inspiring. This new STEVSHARK®REX is a perfect example of how we support our customers in optimising production, minimising downtimes and speeding up their operations.”

Download the STEVSHARK®REX brochure

Vice President Zimmermann also underlined the essence of constant innovation. “If you want to be successful in developing the right products, you must first be able to identify trends as early as possible. Only then can you gain a full understanding of drivers behind future offshore projects. We at Vryhof develop technology that enables our clients to meet future challenges, even before they are recognised in their projects or by their customers. That ability makes our company unique and guarantees the sustainability of Vryhof as leaders in the business.”

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Worldwide testing

The main goal of developing the STEVSHARK®REX was to expand the suitability domain of drag embedment anchors in challenging geotechnical areas. One of those areas is the Arctic, with its hard soil conditions, subsea permafrost, complex gravelly soils and over-consolidated clays or tills. Other difficult areas in terms of sub-seabed types include Australia and the United Arab Emirates, typically with the complex cemented soils of carbonite origin or calcarenite to calcilutite to limestone rocks. The future floating wind farms or other renewable energy development areas are located in relatively complex geological settings where standard anchors may not work.

Senol Ozmutlu added: “While developing the STEVSHARK®REX, we observed the penetration behaviour, stability and capacity of the ‘old’ STEVSHARK® anchors. Combining these observations with rock excavations and cutting knowledge, we identified the critical features of this new anchor. But even before we start building scale models, we kind of need to solve the problem in our mind. What can we expect when you start to drag something in such hard soil or soft rock? What will happen to the material on the seabed? What should an anchor look like in order to penetrate into the seabed?

Essentially, the first step is to develop a conceptual model in your mind, which can be passed on to the designers for further detailing on the drawing board.” The outcome of this passionate and iterative conceptual model development process has resulted in a totally new anchor with radically new fluke and shank geometries.

The Projects Director continued: “After testing several fluke and shank models at laboratory scale, the best model is selected, produced in 7 kg size and extensively tested in our R&D Centre. The laboratory scale tests were conducted in different soils, such as sand, clay, gravel and in an industrial material conditioned to stiff properties. Only after satisfactory laboratory tests did we produce the model scale test anchor of 7 tons for eld testing offshore. In 2016, the offshore tests were carried out at two oil fields with hard sub-seabed soil conditions. A total of 15 tests were carried out at three locations selected by a major Norwegian oil operator. The selected test locations are famed for their anchoring problems where the MODUs had to use piggy-back anchors to reach the required holding capacity. Each and every test proved successful, even exceeding our expectations.” Depending on the location, the holding power of the STEVSHARK®REX
 proved to be 22% to 47% higher than the older STEVSHARK® version. A tremendous result.

Watch the 7mT Prototype test of STEVSHARK®REX:

 
 

Production efficiency

Nonetheless, Vryhof Anchors continues to accumulate more test and experience data with the STEVSHARK®REX For that purpose, two bigger anchors of 18 tons in size were built and shipped to the United Arab Emirates and Australia. The anchor in UAE is currently being used by a rock cutter suction dredger on cemented soils and calcarenite bedrock. The initial results received from the field are positive. The anchor in Australia shall be tested soon in areas with hard soils and carbonate rocks. The test sites are selected in collaboration with a major Australian oil operator. After these trials, the anchor is scheduled to be used by MODUs, which will set the anchor in different fields with challenging soil properties – a challenge STEVSHARK®REX can accept with ease.

Scope of work

Vryhof Anchors designs and installs offshore foundations and mooring systems and components for permanent and temporary floating units. In the oil and gas sector, these include permanently moored FPSO, FSO, FPU, FSRU, SPM, CALM systems and temporary (mobile) systems, including drilling rigs, drill ships, pipe-laying vessels, construction barges, heavy-lift vessels, etc. In the renewable energy sector, applications include floating wind turbines, floating wave, tidal, and current devices. In the civil and construction sector, the units in question include floating platforms and barges for a variety of purposes (e.g. tunnel construction, barrier construction, pipe-pulling, etc.) and dredging applications.

Download the STEVSHARK®REX brochure

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