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Reducing safety risks during offshore wind installations

Cranemaster shock absorbers and passive heave compensators have been used in many offshore wind projects, for installation of monopiles, jacket foundations, monopile templates and transition pieces. Cranemaster units are designed to protect both the crane and the equipment from shock loads and excessive forces.

For offshore wind installations this is resulting in reduced downtime for the installation, increased operational weather window and reduced risk of damaging equipment and personnel.


Typical applications where Cranemaster should be considered

  • Lift-off from barges (feeding). Cranemaster will reduce DAF and therefore increase the operational weather window. 
  • Splash zone crossing of large objects (monopile templates, mono buckets, jacket foundations with suction buckets). Cranemaster will reduce DAF and reduce probability of slack slings. 
  • Installation of transition pieces (TP) on monopoles from floating vessels. Cranemaster will increase ship stability and prevent rapid heeling.
  • Pile runs or pile drops – protection of crane and rigging against snap loads during piling.
  • Subsea landing and subsea re-positioning or recovery of heavy objects.

Below are given a few examples of operations where use of Cranemaster gives significant reduction in cost and risk.     


Shock absorbers will reduce risk in piling operations

Sudden free fall of the piles during pile hammering due to layering in the soil, so called pile runs, is an increasing concern in the industry. The snap loads following pile runs can be very high, exposing both personnel and equipment to high risk.

In cooperation with key players in the industry, Cranemaster has developed special shock absorbers that will reduce the snap loads to an acceptable level. As a result, risk is reduced, and expensive interruptions in the piling process can be avoided. 

offshore-wind-installation-ii
    


SIMULATION EXAMPLE – pile run with and without Cranemaster

This video shows a simulation example for a pile hammer (weight in air 300T). The hammer falls a distance of 0,8m, and is then stopped by the crane wire.

Without Cranemaster:
Snap load = 964T
Significant ringing effect in the
crane and the pile hammer.

With Cranemaster:
Snap load = 513T
Ringing eliminated. 

 


Increasing operability for splash zone crossing of large met masts

Cranemaster units have been used for installation of large met masts in the North Sea. The structures had a height of 45 meters and weights of 300-400 ton.

Cranemaster performed calculations and lift simulations in close cooperation with the customer. Due to the large suction bucket, the splash zone crossing was a challenge with respect to dynamic forces and stability. Utilizing Cranemaster units, these challenges were overcome, and the structures were successfully installed. 

 


Cranemaster used for installation of transition pieces (TP)

Installation of TPs from floating vessels can be challenging. With a Cranemaster unit equipped with Lock & Release functionallity, vessel heeling is controlled, and snap loads are eliminated. Cranemaster units with SWL of 250 ton were used during the Greater Gabbard project for this purpose as shown in the pictures below.

Cranemaster offshore wind installation

Statement from Cranemaster customer:

"Shock loads from pile runs are efficiently reduced by the Cranemaster shock absorbers. Personnel can work safer and more efficiently, and potentially expensive interruptions in the work have been avoided, saving time, money and operational delays" 

 

Youtube examples of pile runs