OWS has developed a bottom fixed substructure design for wind farms in areas with 70 to 200 meters water depth.

The OWS substructure consist of a suction caisson* in the bottom, a flexible joint between the caisson and a conical shaped tower, boat landing, ladders, a platform and a flange for bolting of the WTG tower on the top of the substructure flange.

A mooring spread is required to secure stability when the WTG is installed.

* The sucction caissons can be replaced by other types of bottom supports, depending on seabed conditions.

The OWS Substructure can be fabricated, loaded-out and transported in horizontal position.

Once in position, the horizontally floating OWS Substructure, is upended to a vertical position by water ballasting.

The skirt of the suction caisson will be fully embedded in the seabed by use of suction pumps. Solid ballast might be added in the open compartment on top of the caisson, if required (saving steel weight of the seabed foundation).

Suction pile anchors, or other types of anchors (depending on seabed conditions), will be pre-installed. Hybrid mooring lines will be used between the anchors and the substructure and will be designed for single-line failure. Infield cables to be installed and buried prior to deployment of mooring lines to the substructure. The substructure is stable due to a net positive buoyancy prior to installation of the WTG, without mooring lines attached. The mooring lines will be pre-tensioned using a tensioning device on the substructure or by inline tensioner.