The world’s first offshore jacket fabricated with prefabricated composite joints reaches next industrial milestone
Tree Composites has achieved another important milestone in the industrialisation of composite joint technology for offshore wind foundations. Following successful fabrication and structural validation at the Smulders-HSM fabrication yard in Schiedam, the WrapNode-II demonstrator jacket has arrived at the Tree Composites facility in Delft.
The transport marks more than the relocation of a demonstrator. It represents the completion of the world’s first industrial fabrication of an offshore wind jacket using prefabricated composite joints instead of conventional welded tubular TKY nodes.
A new approach to offshore jacket fabrication
The WrapNode-II demonstrator is the first offshore jacket to be assembled using prefabricated composite joints connected by circumferential welds only. By eliminating complex welded tubular nodes, this innovative fabrication approach has the potential to simplify manufacturing, improve fatigue performance and enable more efficient serial production of offshore wind jacket foundations.
Working together with Smulders-HSM, Tree Composites has successfully demonstrated that composite joints can be integrated into an industrial fabrication environment while meeting the structural performance requirements for offshore wind applications.
Successful structural validation
Before leaving the fabrication yard in Schiedam, the demonstrator underwent an extensive structural validation programme performed by TU Delft. The programme confirmed the structural integrity of the composite joints under representative offshore loading conditions, including:
- Static loading up to 150% of the Ultimate Limit State (ULS) design load
- Dynamic fatigue loading equivalent to 35 years of offshore operation
- No signs of degradation throughout the test programme
These results provide further confidence in the application of composite joint technology for future offshore wind structures.
Supporting the next phase of commercialisation
Now located at the Tree Composites facility in Delft, the demonstrator will support the next phase of the WrapNode-II programme. It will be used for industry demonstrations, customer visits and commercialisation activities, allowing project developers, fabricators and supply chain partners to experience the technology firsthand.
The demonstrator also forms an important stepping stone towards the recently launched European JOIN2SCALE programme, which focuses on scaling composite joint technology for industrial deployment across the offshore wind sector.
Demonstration Day – October 2026
Tree Composites will host a Demonstration Day in October 2026, where industry partners will have the opportunity to inspect the world’s first composite joint jacket, learn more about the technology and discuss the next steps towards commercial deployment. More information on the event will be shared in the coming months.
A collaborative achievement
This milestone was made possible through the collaboration of the WrapNode-II consortium and the support of the Netherlands Enterprise Agency (RVO).
Tree Composites would like to thank all consortium partners for their contribution. Special thanks go to Smulders-HSM for successfully fabricating the world’s first composite joint jacket, Mammoet for the safe transport and installation, and Gemeente Delft and Provincie Zuid-Holland for facilitating the transport to Delft.
The successful completion of this demonstrator represents another important step towards the large-scale industrial deployment of composite joint technology, supporting a more competitive and sustainable European offshore wind industry.
See the video here:
