As part of a collaborative scope for one of the biggest offshore wind farms in the world, ALE and their Conbit operation have reached the half-way milestone for the marine transportation, sea-fastening, load-out and ballasting of over 100 transition pieces (TPs) for Ørsted’s Hornsea Project One.
Utilising its innovative equipment and structural engineering expertise, ALE has been able to find a safer and more cost-effective heavy transport solution.
ALE has been contracted by GeoSea to provide the specialist offshore engineering as well as the marine transportation, sea-fastening, load-out and ballasting of over 100 transition pieces (TPs) for Ørsted’s Hornsea Project One.
For the structural engineering, the Conbit team performed the structural integrity and sea fastening calculations of the grillages on the barge deck of the SARAH S barge – ALE’s latest marine investment.
ALE began their heavy lifting and transportation scope in March, loading-out the TPs, each weighing 337t and measuring 25m high, from the fabrication yard onto the barge and performing the sea-fastening and marine transport.
Once on the SARAH S barge, the TPs are transported on the River Tees to the discharge berth. The SARAH S is 3m narrower than most North Sea barges, making this innovative barge ideal for the project, as it can fit between the quayside and the offshore installation vessel, and falls in line with the vessels’ crane radius limits for transferring the TPs from the barge to the installation vessel.
Conbit also provided the engineering for cost-effective storage and SPMT stability during the ALE transport operations at the yard. As ensuring stability during the SPMT move was challenging, Conbit provided the engineering to enhance the hydraulic stability during the monopile positioning in relation to the sling configuration (used for loading onto the SPMTs) and positioning within the support cradles.
For the storage at the quay, Conbit designed monopile cradles. These were specifically optimised to reduce costs, as the need for welding works is reduced.
“This project demonstrates our ability to offer the full, specialist marine scope of work. From utilising our internal expertise and engineering unique solutions, to offering an extensive fleet and operative skills, we can manage the complete project,” explains Steve Small, Commercial Manager – Marine.
Bart Steerneman, Engineering Manager for Conbit, said: “Using our in-house expertise, we could provide a cost-effective and safer solution for ALE to perform the heavy transport operations. This project shows the strength of the ALE – Conbit collaboration, as we are now able to provide clients with the complete service package, from transport to engineering and stress checks.”
So far, ALE has loaded-out and discharged 54 of the contracted 106 TPs onto the installation vessel. The operations are expected to last until early 2019.