Houlder Installs Pile Gripper Arms on MPI Discovery (UK)

Houlder has installed 650t pile gripper arms on the MPI Discovery jack-up vessel.

“The challenge of handling offshore wind turbine piles has grown along with their size,” commented Frederic Perdrix, Chief Technical Officer, as Houlder delivered its latest piece of bespoke equipment.

The pile Gripper Arms, installed this week, stabilise 6m diameter 650t steel piles as they are driven into the seabed by the MPI Discovery installation jack up vessel. Installed on the vessel’s stern below deck level, they provide resistance to wave, tide and current forces in water depths of up to 40m. Their position and the additional control this provides significantly reduces installation times providing a valuable enhancement to the Discovery’s capability.

Frederic went on to say: “MPI’s specific requirement was a great opportunity for our engineers to demonstrate their ingenuity and ambition. The result combines heavy duty structural, mechanical and hydraulic engineering with precision control.”

Peter Robinson, Managing Director of MPI Offshore Ltd said: “We are delighted with the final engineered solution created by Houlder Ltd. Both their engineers and ours have worked in collaboration to construct this equipment to exacting standards. Such innovation is part of MPI’s on-going development, and will provide demonstrable improvements to the monopile process for our clients.”

The hydraulically driven arms, weighing circa 90t each, have three main cylinders: one to deploy the arms from their stowage position and two to provide a horizontal gripping motion able to withstand up to 150t of horizontal load in any direction. These cylinders are actuated by touchscreen and single joystick controls that allow an operator to engage the arms, close the jaws and then maintain the pile in the vertical plane as it is hammered down. Any risk of operator caused collision is reduced through automated constraints based on the pile diameters.

Houlder’s Project Manager, Andy Lovell, added: “The contract was managed by a dedicated team from Houlder’s Tyneside office and used engineering capability from company offices across the UK. Houlder acted as MPI’s design and engineering partner from initial concept design through to delivery. This included deck arrangements which, given the constraints of a working installation vessel, focused on minimising the required footprint. The company also designed and validated the foundations and required deck modifications.”

The Gripper Arms project cements Houlder’s position as a key supplier of bespoke equipment to those tasked with installing and maintaining offshore wind farms. The company’s reputation for overcoming the industry’s challenges continues to grow.

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Press release, August 16, 2013; Images: Houlder