The WTIV is designed for installation of present and future size (22 MW+) of wind turbine generators (WTGs).
The WTIV can install WTGs for both bottom fixed- and floating substructures offshore.
The WTIV being employed 100 % at the offshore installation site and WTG components being transported by feeder vessel for load transfer to the WTIV, shorten the offshore installation period and allow for early production of electricity.
The heave compensated cranes allow for smooth load transfer offshore.
The WTG upper tower sections can be transported horizontally (simplify load transfer) and upended by use of the tandem cranes.
The methodology simplifies logistics, with no need for an inshore site for the assembly of floating WTGs (installation of the tower onto the floating substructure, installation of the nacelle with the hub onto the tower, and installation of the blades onto the hub), and only a limited marshalling site is required.
The WTG towers, nacelles and blades are fully assembled to one unit on the deck of the WTIV (without relative motions). The interaction between the WTIV and the substructure, during installation, reduces thereby from day(s) to hour(s).
The methodology allows for weight reduction of floating substructure, since they only need to be designed for deep water operation and not for shallow water, as required for inshore assembly and tow out.
The WTIV can also be employed during offshore maintenance of floating (and bottom fixed) WTGs, without the need towing floating WTGs to inshore location for maintenance.
The WTIV is also suited for other offshore work as a Semi Submersible Crane Vessel (SSCV).
