ALE complete heaviest skidding operation

ALE has skidded the forward section of the second aircraft carrier, weighing 26,500t, for the HMS Prince of Wales in Rosyth Dockyard, UK. This is the heaviest item to ever be skidded by ALE.

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ALE was contracted by Babcock International Group on behalf of the Aircraft Carrier Alliance to jack-up and skid a total of four sections, one lighter and one heavier sections per ship as part of a major contract for the aircraft carrier project. In 2013 ALE completed their scope for the first warship, HMS Queen Elizabeth and in October skidded the final sections for the second warship, HMS Prince of Wales.

The operation involved jacking-up and skidding two sections, weighing 13,050t and 26,500t respectively. Firstly, ALE jacked-up the sections from their support, skidded the lighter section approximately 94m and the heavier section approximately 18m.

The skidshoes used for the skidding operation consisted of a built-in jacking system that could be easily installed under the specially designed building supports. The supports had been placed on five rows of dock blocks to prevent sagging and provide easy access under the sections.

ALE used a total of 35 skidshoes for the lighter module and 58 skidshoes for the heavier module, both with a minimum capacity of 500t. 800m of skid track was required to skid the lighter section and 650m used to skid the heavier section. 1,000t of spreader plates were fabricated to suit the skid shoes, with the ability of the wings on the bow to be taken off in an earlier stage to speed up the lead time of the project.

During the final stages of the skidding operation ALE crew members maintained constant contact with the Babcock International’s dimensional control team to manipulate the sections as best as possible to create a suitable fit-up to the other sections.

Tim van As, Project Engineer, who oversaw the engineering and managed the skidding operation, said: “This is the first time ALE has ever attempted to skid an item of such an extreme weight. We complied with the strict security and safety standards throughout and during the operation we overcame several challenges.

“It is fantastic to be part of what could potentially be a world first in skidding capabilities. By utilising our global network of equipment and technical expertise from the UK, Spain and the Netherlands to complete this operation, we are all proud of what has been achieved.

“These installations represent a major milestone towards the completion of our overall scope and the construction of the largest warships ever to be built for the Royal Navy.”

ALE are currently continuing to work on the operations for the second HMS Prince of Wales aircraft carrier.