Tech Files

Mooring Systems, Anchor Handling & Station Keeping

Staying Anchored

Credit: Island Offshore

In this product feature edition of Offshore Engineer is looking at recent news and developments in the space of offshore moorings and anchors. While some time back this section would be brimming with oil and gas-related content, there's now an increasing role of renewables, too.

Still, to start things off, let's begin with a feat by the Norwegian offshore vessel owner Island Offshore which recently, in its own words, broke a world record during pre-laying of anchors for the West Bollsta semi-submersible drilling rig in Norway, using its Island Victory vessel.

During the operation at Lundin Energy's Solveig field, the anchors were fastened by pulling them with such great force that they embed themselves into the seabed.

„In cases where a significant degree of force is needed this is done "in tandem" by two vessels. Island Victory, however, did it all on her own!," Island Offshore said.

According to Island Offshore, 440 tonnes of continuous traction on an anchor counts as a world record and has never been done by one vessel alone before.

and has never been done by one vessel alone before. "A total of eight anchors and anchor lines were laid out, ready for hook-up to the rig West Bollsta. Lundin Energy Norway is the operator of the oilfield, with Island Crusader on contract as the support vessel of West Bollsta," Island Offshore said.

The anchors in question were Vryhof's STEVSHARK®REX drag embedment anchors, and were installed in preparation for the West Bollsta drilling rig. Read on to learn more about Vryhof anchors, and other recent mooring/anchors/services news and products.


Vryhof_STEVSHARK®REX Credit: Vryhof

According to Vryhof, STEVSHARK®REX anchors are suited to more challenging soil conditions, have high holding power, and are installed by embedding themselves into the seabed.

Describing the operation at the Solveig field, Vryhof added: “Over a period of just two days, all 8 STEVSHARK®REX anchors were installed without any issues at a water depth of around 100 meters, ready for hook-up to the rig.

“This area has historically been difficult to work in and often requires anchor resetting or piggy back anchors. The STEVSHARK®REX is designed to penetrate the seabed quickly, resulting in a shorter drag length during installation. This results in reduced time offshore and the associated cost savings.”

Although specifically developed for anchoring in areas with hard soils, the new STEVSHARK®REX can be set at different fluke/shank angles, allowing adjustment to successfully anchor in softer soils without having to change the anchor type.

Acteon’s Bruce Anchor

Credit: Acteon

Bruce Anchor is a Moorings and Anchors product and service line brand in marine and energy infrastructure services group Acteon.

After rigorous testing in collaboration with DNV, to gather the required data for their ‘DIGIN’ software, the Bruce GP anchor has been added to the DIGIN program.

The DIGIN program provides a scalable anchor database and allows users to predict the anchor behavior during installation. A DIGIN report is required before any installation on the Norwegian Continental Shelf.

The test results were excellent, and through DIGIN, Acteon can now offer a detailed report for the anchor’s expected embedment behavior and holding capacity, prior to a client’s anchor selection process being finalized, Acteon said.

According to Acteon, the Bruce GP anchor has the largest fluke area and the highest holding capacity of any drag embedment anchor (size for size) available on the market today.

Sustainable Marine’s Swift Anchors

Credit: Sustainable Marine

Sustainable Marine’s Swift Anchors division provides anchoring solutions for marine projects and is driven by the requirements to have a low cost, rapidly deployed, and robust anchoring solution.

It provides a solution for all marine environments, and a wide range of seabed types including rock, overburden, and soft sediments. It has been under development for more than a decade with a mission to provide greener, faster, and cost-efficient solutions compared to traditional clump weighs and gravity anchors.

Its portfolio includes Groutless Rock Anchors, Screw Anchor Piles, Drag Embedment Anchors and Grouted Self-Drilling Piles. The one-tonne steel anchor can provide the same holding force as 750 tonnes of concrete. Aside from carbon offsetting benefits, it will reduce the environmental impact footprint on the seabed and drive down logistical costs with rapid installations managed by smaller vessels. It is estimated that it can generate up to 70 percent in cost savings compared to traditional systems for small arrays.

Worth noting, ORPC has engaged Sustainable Marine’s Swift Anchors division to provide its novel rock anchoring system for its Advanced TidGen Project set to launch in Maine later this year. Read More Here

Remazel Engineering: Mooring technology from Oil&Gas to Floating Wind

Credit: Remazel

Italian company Remazel, specializing in the design and manufacturing of mooring systems for FPSO & FLNG applications, has recently secured a contract to deliver mooring tensioning system and riser pull-in package for an FPSO being built for deployment at ExxonMobil's Stabroek block in Guyana. Read More Here.

However, for this feature, Remazel has shared with Offshore Engineer that it has developed new solutions for Floating Wind to contribute to green energy boost and environmental impact reduction.

The floating wind market fundamentals are clear: reliable, straightforward products and standardized solutions to reduce LCOE by scale economy. Remazel has already studied specific products for the firsts floating wind pilot projects to be delivered in the upcoming months, the company said.

Remazel’s mooring solutions for floating wind are based on CHAIN, STEEL WIRE ROPE, and SYNTHETIC ROPE, both for Semi-sub both for TLP/SPAR, customized on customer projects specific requirements.

The tensioners for the mooring lines are positioned onboard the floaters, close to the anchor, or inside the mooring line (in-line) and can be based on active or passive equipment.

The same solutions can be applied to any kind of Floaters: Wind farms, Aquaculture, Desalination, and hybrid solutions, Remazel said.

Kraken Bringing Cost Savings to Mooring Chain Inspections

Credit: Kraken

Canada’s Kraken Robotics in partnership with the offshore energy industry and the government is developing SeaVision® Mooring Chain Inspection Tool (MCIT), an underwater mooring chain inspection tool based on Kraken’s SeaVision sensor. SeaVision is a mature Kraken technology that produces ultra-high resolution underwater 3D laser-imaging scans and has been deployed successfully in diverse mooring campaigns in Canada and Brazil.

With SeaVision MCIT, Kraken is also developing the data analytics software to process SeaVision® data efficiently into corrosion and dimensional measurements requirements for mooring integrity analysis.

Kraken’s SeaVision MCIT tool has been described as a substitute to the conventional mechanical caliper used today for dimensional measurements.

According to Kraken, this advancement provides a faster, contact-free measurement that reduces the number of campaign days, consequently saving millions of dollars in operational costs and CO2 emissions associated with vessel operations.

Ashtead - Remote Inspections

Credit: Ashtead

Ashtead Technology is continuing to drive remote and unmanned technology innovations in 2021, with development of a new optical Chain Measurement System (CMS) reducing measurement time by up to 70% and launching the Unmanned Digital Twinning project in collaboration with Canada’s Ocean Supercluster.

The company has said remote inspection services are seeing exponential market growth in the asset integrity sector.

Ashtead completed five remote underwater inspection projects in Q1 2021 from remote operations centers in Aberdeenshire, UK, and Canada. To date, projects have been delivered in Angola, Australia, and the UK for the likes of Shell, BP, and Woodside, with upcoming projects in Malaysia, Canada, and the USA.

Some of these clients required remote operations due to travel restrictions, while others have opted for remote operations instead of conventional manning to reduce cost and lower POB.

After first launching remote operations services for Class-approved mooring system UWILD inspections in 2020, Ashtead has expanded to offer fully-remote 3D photogrammetry services as well.

Lankhorst Offshore - Gama98 Dyneema DM20 mooring rope for Floating Wind

Credit: Lankhorst Offshore

As wind energy production moves further offshore, and water depths increase, fiber rope mooring lines hold the key to the successful deployment of floating wind turbine generator (WTG) platforms, according to Lankhorst Offshore.

The company has developed the Gama98 Dyneema DM20 mooring rope to provide a soft catenary mooring system for floating wind turbines.

The rope’s combination of flexibility and stiffness ensures a resilient mooring for long-term offshore deployment, while restraining the platform’s horizontal movement. Moreover, the ease of High Modulus Poly-Ethylene (HMPE) rope handling results in significantly lower costs compared to spiral strand steel wire both during installation and future disconnection, Lankhorst Offshore said.

Reduced project installation costs are achieved through the use lightweight mooring line components and smaller vessels. Furthermore, no mooring line pre-tensioning required, while the rope has limited rope constructional elongation (<1%).

Gama98 Dyneema DM20 fibre ropes have been used for the Wind Float Atlantic project offshore Portugal.

May - June 2021 E-mag