[Schiedam, 30-11-2025] The HSI consortium, comprising HSM Offshore Energy, Smulders, and Iv, is proud to announce the successful yard completion and sail-away of the Jasmund Offshore Substation (OSS), measuring 48 meters long, 33 meters wide, 17.5 meters high, and weighing approximately 4,500 tons, from the HSM Offshore Energy Stormpolder yard. This milestone is complemented by the departure of the associated 72-meter-high jacket from the Smulders yard in Vlissingen.

A spectacular departure through the heart of Rotterdam

The sail-away of the topside marked a significant project milestone and created a remarkable moment for the city of Rotterdam. As the massive structure made its way through the historic city center, it stood in striking contrast to the urban skyline and the city’s iconic bridges. The journey not only highlighted the impressive engineering behind the topside but also emphasized Rotterdam’s strong maritime heritage.

On route to the Baltic Sea for offshore installation

The topside and jacket are now on their way to the next stage of the Ostwind 3 project. In the coming weeks, they will travel to their final destination northeast of the island of Rügen in the Baltic Sea, where offshore installation will be carried out by Heerema Marine Contractors. Once operational, OSS Jasmund will have a planned capacity of 300 MW. It will serve as a crucial connection point between the Windanker wind farm and the onshore electricity grid.

Hans Leerdam, Chief Commercial Officer of HSM Offshore Energy, commented: “The successful sail-away of the OSS Jasmund topside is a testament to the dedication, expertise, and seamless collaboration across the HSI consortium. Guiding such a massive structure through the center of Rotterdam was not only an impressive achievement but also a proud moment for everyone involved.”

Wim Vaes, Commercial Director Smulders, “The sail away of the OSS Jasmund jacket marks a major achievement not only for our Vlissingen yard, but also for every team within the consortium. From jacket assembly and outfitting to preparing for the topside integration offshore, this milestone clearly reflects the strength of our collaboration and shared commitment to excellence. Furthermore, we are proud to have delivered this safely. This would not have been possible without the dedication of our employees, who all take our strict safety policy to heart.”

Fedor van Veen, Managing Director Offshore & Energy at Iv: “Seeing the Jasmund OSS leave the yard is a defining moment. A sail-away like this reflects the close collaboration within the HSI consortium and brings together years of engineering and construction. Watching the topside pass beneath the Brienenoord and Erasmus bridges was a memorable moment.”

Delivered for 50Hertz

The OSS Jasmund is being delivered for 50Hertz, with the HSI consortium responsible for the full EPCIC scope (Engineering, Procurement, Construction, Installation and Commissioning). It is the first of three offshore substations that the consortium is developing for 50Hertz, with the Zingst and Darß substations to follow. Together, these three platforms form part of the Ostwind 3 and OST-6-1 projects.

Proud collaboration for Europe’s energy transition

The successful sail-away of both structures underscores the strength of collaboration within the HSI consortium and marks another significant step in supporting Europe’s expanding offshore wind capacity. The consortium remains committed to delivering safe, efficient, and high-quality offshore infrastructure that accelerates the renewable energy transition across Europe.