I.6.1.1 Turbine handling equipment and sea fastenings

Function

Turbine handling equipment is used to assist in the lifting and manipulation of turbine components during loading in port and installation offshore. Handling equipment is typically developed by the turbine supplier to be specific to a given task and component. There are several handling tools required for offshore installation including tower handling tools, nacelle handling tools and blade handling tools. 

Sea fastenings are used during the transport of heavy and costly components from the Construction port [I.7] to site.

What it costs*

Included in turbine installation cost.

Who supplies them

Component handling tools are often provided to the offshore contractor by the turbine supplier as the tool is specific to a turbine type and installation methodology.

Key facts

There are several approaches to reducing the sensitivity of turbine component lifts (especially the blades) to high winds, thereby reducing weather downtime:

• The blade still hangs from the crane hook, but is supported in a frame with a hydraulic assembly to allow the blade to be rotated remotely to the preferred orientation, the position of the blade also being constrained by a series of remotely controlled ropes
• A lifting tool with a four-part attachment: two tag lines from the crane and a third running from a bracket fixed to the tower enables the blade position to be controlled in wind speeds up to 13 m/s regardless of direction
• Rigid support of the blade so that at no point is its position influenced by wind loading, and
• Hook stabilisation tools that reduce hook movements due to wind.

Currently, blades can be lifted in winds in wind speeds up to 13 m/s. Although this limit could be raised in theory, there comes a point where high winds make work on deck hazardous, even if the turbine installation can, in theory, be continued.

Sea fastenings are structures located on the deck of the installation vessel, which allow for the safe transportation of turbine components from the Construction port [I.7] to the installation location. Typically, large steel fabricated structures and frames secured to the main deck of the installation vessel. 

Sea fastenings are designed to transfer the load of the component into the vessel structure and keep the component in position without damaging the component or vessel. Sea fastenings must also be designed to allow safe access of technicians both during transportation for inspections and to release the component to allow lifting.