C1 Connections and Heerema Marine Contractors successfully test the C1 Wedge Connection offshore

November 7, 2022 | Renewables | Energy Facts Staff Writer | 2min

C1 Connections BV and Heerema Marine Contractors have successfully tested the C1 Wedge Connection™ offshore. The C1 Wedge Connection™, developed by C1 Connections BV, is a high-capacity connection that can be installed faster and safer than conventional bolted flange connections. It can be used in off- and onshore wind turbines, both in turbine towers and foundations. The installation of the tower on board Thialf was performed as part of the preparations for the Arcadis Ost project, for which Heerema will install 27 wind turbines for the Belgian developer Parkwind.

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The C1 Wedge Connection™ can deliver the high capacity that is needed for the next generation wind turbines, which continue to grow in size and are installed on sites in increasingly harsh environmental conditions or on floating platforms. The C1 Wedge Connection™ will improve the LCOE by reducing CAPEX and OPEX while allowing safer installation.

Conventional bolted L-flange connections are reaching their capacity limits and are complex to design, install and maintain. This is where the C1 Wedge Connection™ will make a significant difference. During the offshore test, C1 Connections and Heerema Marine Contractors demonstrated that the C1 Wedge Connection ™ enables a safe disconnection of the tower from a grillage on a barge. 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 development of the C1 Wedge Connection™ started in early 2017 in close collaboration with Delft University of Technology (TU Delft). From the offset, this technology has received support from the Dutch Government Agency RVO, with several industry partners contributing to its further optimization.

Jasper Winkes, Managing Director, C1 Connections B.V.: “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.”