A Sea Change for Offshore Installations

As wind turbines get bigger, in increasingly harsh environments or on floating platforms, conventional bolted L-flange connections are reaching their capacity limits and are complex to design, install, and maintain. 

The C1 Wedge Connection™, developed by C1 Connections BV, is a disruptive fastening technology that can deliver the high capacity needed for this new generation of wind turbines. 

Turbine towers can be aligned to the foundations without personnel. The C1 Wedge Connection features a remotely actuated instant quick connection for a fast and safe release from the crane hook, after which operators can enter safely, push in the fasteners and apply the final preload using handheld Boltight™ hydraulic tensioners. 

Traditional L-flange connections are also exposed to sea corrosion, whereas the C1 Wedge Connection is designed so the most critical parts stay dry, mitigating corrosion. 

During a successful offshore test with Heerema Marine Contractors, C1 Connections demonstrated that their solution enables a safe disconnection of the tower from a grillage on a barge. A joint press release details how “the alignment and quick connection of the tower was successfully performed without any personnel below the suspended load. The C1 Wedge Connection features pre-installed fasteners, and only lightweight tools are needed to finalize the connection.” 

The technology is DNV certified as C1 Connections demonstrated that the connection works, has tested fatigue and ultimate capacity, and it can be built full-scale for large wind farms. 

Nord-Lock Group meets C1 Connections with a common goal to simplify bolting assemblies, protect workers and build more robust applications. 

Christophe Cuypers, Nord-Lock Group Tensioning Key Account Manager, says “I am extremely pleased that Nord-Lock Group can support this innovation with the design and testing of custom Boltight hydraulic tensioners - used to accurately pre-tension the C1 Wedge Connection.” 

This collaboration is strategically important to demonstrate that offshore installation can be made much faster and safer, at the same time as improving the Levelized Cost of Energy (LCOE) by reducing CAPEX and OPEX. 

In Heerema’s press release, C1 Connections BV Managing Director, Jasper Winkes, says that “prior research and testing have demonstrated that the C1 Wedge Connection delivers a very high fatigue and ultimate capacity. The collaboration with Heerema has allowed us to demonstrate offshore that we can make installation much safer and faster, which are key benefits the entire industry can benefit from.” 

Watch the video from C1 Connections here: C1 Wedge Connection offshore test