Sarens Designs Ingenious Gantry System for Lifting Differently-Sized Monopiles
Sarens’ time-saving solution empowers client to move monopiles swiftly and efficiently
August 2023

Sarens recently completed a project on behalf of client EEW Special Pipe Constructions GmbH, experts in producing monopiles that serve as foundation piles for offshore wind turbines. 

So that EEW SPC could offer their clients greater flexibility from their yard in Rostock, Germany, they asked Sarens to engineer a solution for lifting monopiles from their transport combination and into clients’ cradles. These cradles are designed to support and secure the monopiles on deck carriers during transfer at sea.

Because of our previous experience on projects like Fécamp, Sarens was able to design a flawless solution that would fit EEW SPC’s needsfec like a glove. 

The main challenge to address was that each monopile had different dimensions, weighing between 375 and 1.900 tonnes with a 23-85 metre length and diameter variation between 8-9,75 metres. To accommodate every possible type of monopile, Sarens designed a system with two gantries capable of lifting 1.900 tonnes. The two gantries were engineered to a height of 24 metres and width of 25 metres, and positioned atop two tracks of steel mats. Each was equipped with two 650-tonne strandjacks connected to a spreader bar to handle all possible monopile diameters. 

So that the lifting system could be adapted to the required longitudinal lifting position for each monopile, one gantry was designed to be moved via SPMTs. This ensured a maximally flexible system for handling differently-sized monopiles.

A key challenge Sarens had to address during the design phase was the time pressures inherent in such projects: the team had to minimise time used in execution as installation vessels would be waiting. As a result, Sarens engineered a time-saving system that would connect and disconnect the slings in a very short time. Sarens engineers worked closely with senior operational colleagues to find the best possible solution and equipment to pull this off.

Sarens presented the completed solution in March, when the system went into operation to the client’s satisfaction. We are proud to have been part of designing this ingenious solution and would like to congratulate the engineering and operations teams that made it possible!