Allseas’s Pioneering Spirit lifts entire offshore platform topsides of up to 60,000 tonnes in a single lift and jackets of up to 20,000 tonnes, according to the company’s vessel page. The same ship has a 2,000-tonne S-lay tension capacity, and Allseas says its 2,000-tonne pipe-holding capacity is double that of any rival pipelay vessel.

Allseas describes the ship as “the world’s largest and most versatile construction vessel” and says it “represents a step change in offshore engineering”.

The vessel was purpose built to transport, install and remove whole platforms in one go. Allseas says the single-lift method reduces offshore exposure, “transferring complex activities onshore where they are safer and more cost-effective”, and that this trims risk, cost and development timelines.

Allseas says the ship was engineered entirely in-house and can also carry and install the largest offshore wind substations.

The company also lists “unique motion compensated, single-lift technology”, the installation of large subsea structures close to live infrastructure, and what it calls high workability in hostile areas with less sensitivity to weather.

What it has lifted so far

The vessel’s first heavy lift job for the offshore industry came in 2016, when it removed the complete 13,500-tonne Yme mobile offshore production unit in a single lift, transported it and loaded it in to shore.

In 2019 it installed the drilling, process and accommodation platform topsides for the first phase of the Johan Sverdrup field in the Norwegian North Sea. The same year it removed the original Valhall QP accommodation platform, topsides, jacket and bridge included, from the Norwegian North Sea.

In 2020 it removed the complete 23,000-tonne Ninian Northern platform from the North Sea in one lift and carried it to shore for disposal, with the Iron Lady and the Oceanic also listed on the job.

In 2022 the ship removed the complete 30,000-tonne Gyda platform from the Norwegian North Sea for recycling, installed a second process platform topsides at Johan Sverdrup, and transported and installed the 900-megawatt DolWin Kappa converter station for the DolWin6 grid connection in the German North Sea.

Several of those jobs also used the Iron Lady, a special purpose barge that Allseas says enables topsides transfers in shallow waters with a ballast system.

A second barge, Braveheart, was due to arrive in late 2025 with an electric ballast system and tidal compensation, according to Allseas.

Pipelay mode

Allseas also calls the ship “the world’s largest and most advanced pipelay vessel”.

The Allseas page gives the 2,000-tonne figure both as S-lay tension capacity and as pipe-holding capacity.

Allseas says that capacity lets the ship install pipelines “of record weight from shallow to ultra-deep waters”, with 12 azimuth thrusters handling positioning. A double-joint factory, six welding stations and pipe storage on board allow continuous pipelay, the company says.

Allseas says the storage capacity allows “uninterrupted pipelay campaigns”.

The ship completed its GTA infield pipelay scope on 20 February 2024.

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