Slip Joint Turbine completes offshore tests

DOB-Academy has shared a video showing the removal of the Delft Offshore Turbine (DOT) as part of the Slip Joint Offshore Research project. The DOT unit was installed at Eneco’s Princess Amalia offshore wind farm (Prinses Amaliawindpark) in the Dutch North Sea in June 2018.

The installation was conducted via a Slip Joint connection, which means the turbine is slid over the monopile without the use of grout or bolts. Heerema Marine Contractors’ Aegir loaded the fully assembled turbine at the quay of Sif Rotterdam and installed it at the site offshore Ijmuiden in floating mode on Dynamic Positioning (DP). Aegir returned once again to Princess Amalia to remove the DOT in August 2019. On 16 August, the complete wind turbine was picked up in a single lift from its monopile foundation to be transported towards and backloaded on the quay of Sif Rotterdam for further onshore decommissioning.


With the removal of the wind turbine, all necessary data regarding the Slip Joint connection is successfully gathered and is now being processed and used for validating by the project partners, DOB-Academy said.

The Slip Joint Offshore Research project (SJOR) was initiated by DOT BV, part of DOB-Academy, in 2016 and is a collaboration between TU Delft, TNO, Van Oord, and Sif group, as well as project stakeholders Eneco and Heerema Marine Contractors.

Source:, illustration DOT Power

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