25.11.2020

Larger SK from Mammoet

Mammoet has unveiled a few preliminary details of the SK6000 - a larger 6,000 tonne version of the ALE containerised heavy lift crane concept used on the SK 190 and SK 350, which in turn were based on the SK90 and SK 120, see: ALE SK rebrand and ALE SK clarifications. Mammoet completed the acquisition of ALE (Abnormal Load Engineering) in January see: Mammoet completes ALE acquisition.
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The SK6,000

The larger SK has been conceived to keep up with new more efficient methods of constructing Floating Production Storage and Offloading (FSPO) and Floating liquefied natural gas (FLNG) vessels where the hull and topsides are constructed simultaneously out of ever larger modules. This evolution is creating greater challenges when it comes to integrating the larger components.

The SK6,000 potentially allows bulky modules weighing as much as 5,000 tonnes to be handled, helping set new standards for efficiency, safety, and time to production. Even now the modules are regularly exceeding 3,000 tonnes and measuring tens of thousands of cubic metres. Given the loads involved, it can be difficult to bring sufficiently large cranes of lifting equipment to the project site.
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The SK6,000 front view

According to Mammoet the SK6,000 will enable topside modules to be lifted and installed from a single position without any need to rotate the hull, which is a costly and time consuming exercise. Its design comprises what would be a centralised counterweight in a full ring situation, but the SK concept avoids the need to install a full ring track, which can free up considerable space on site. It is also said to apply a particularly low ground bearing pressure.

Sales director Giovanni Alders said: “As our customers strive for greater and greater efficiencies, both in terms of construction and production, the capacity of land based cranes becomes a significant limiting factor when developing the FPSO modularisation strategy.”

“As FPSO designs scale-up, not only are module designs growing larger and heavier, but flare towers are also becoming taller than ever before. With our SK6,000, we can install flare towers of up to 1,500 tonnes and 150 metres in height in a single piece.”

“With its long outreach, small minimum footprint and relatively small site impact, the SK6,000 greatly reduces the topside integration time. Needless to say, with larger building blocks you spend less time connecting and testing, and more time producing.”
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The ballast sits in the centre of the theoretical full ring