Tetrahedron 8 Crane on Display to the Offshore Wind Industry – Heavy Lift News
18 Apr 2024

Tetrahedron 8 Crane on Display to the Offshore Wind Industry

Offshore Wind sector companies and HeavyLiftNews.com were invited to see the first Tetrahedron crane put through its paces onshore in Vlissingen this week.

Before seeing this first crane in action the development, geometry and eventual fabrication, transportation and installation stages of the crane were described by Wilco Stavenuiter (company founder), Alexander Ronse (Engineering Manager), Stephan van der Mel (Senior Structural Engineer), Rick Markestein (Senior Design Engineer).

Five years ago, they realised that the height of offshore wind turbine towers was going to be much higher in the future to accommodate the much larger turbines that were being planned. Conventional cranes on current installation vessels would not be able to reach these heights to install the 20MW turbines and blades in the future.

The Tetrahedron was born. However, to design and build a full-scale installation crane would be beyond their development budget so the Tetrahedron 8 has been built, which is suitable for eventual maintenance work on current turbines and blades.

The speakers heavily emphasised that all of the orange coloured structure of the crane, pendants and boom, is  a rigid, fixed structure, forming the luffing 3D-triangle.

This crane has the following dimensions…

Lifting capacity base reeving:

  • O&M Activities:

160t at 30m radius (4 falls)

250t at 16m radius (6 falls)

  • Blade installation:    120t at 35m, installation at 130m above deck

Fully electric driven

  • Speeds:

Main Hoist 160t Load (4 falls):            12 m/min

Main Hoist Empty Hook (4 falls):        30 m/min

Luffing time                                           10 min full stroke)

 

 

In the Vlissingen dock yard they have simulated the deck of an installation vessel and built this crane is on a foundation frame which set on to a strengthened site and fitted out with 250t of concrete ballast.

 

In cold windy and weather between heavy rain showers the crane boom was lowered from the highest position to the resting position on a cradle made of two containers.

↓↑        The 2 Fibre Aramid Pendants are tensioned using hydraulic tensioners which are then locked with a heavy pin

 

      

 

↓↑   In more clement weather, last week, the 70t load test was successfully performed as reported on HeavyLiftNews.com(photographs courtesy of Tetrahedron)

 

 

 

 

Source with thanks to     

 

 

 

 

 

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