Pioneering Spirit (formerly Pieter Schelte) is a catamarancrane vessel owned by the Switzerland-based Allseas Group designed for the single-lift installation and removal of large oil and gas platforms and the installation of record-weight pipelines. The 382-metre-long (1,253 ft), 124-metre-wide (407 ft) vessel is the world’s largest vessel by gross tonnage and was built in South Korea by Daewoo Shipbuilding & Marine Engineering at a cost of €2.6 billion. It commenced offshore operations in August 2016.
The initial concept, by Allseas technical director W.P. Kaldenbach, was of a vessel capable of lifting entire platforms, and in 1987 Allseas declared its intention to build it. The initial idea featured two rigidly connected, self-propelled supertankers, with a large slot at the bows enabling it to install platform topsides in one piece. Early designs featured a flotation and ballasting system and active motion compensation system to facilitate a controlled transfer of a topsides’ weight from the vessel to a platform substructure. Allseas developed the original idea to include steel jacket installation, jackets and topsides removal and rigid pipelay capabilities.
The emphasis switched from the conversion of two existing tankers to a new-build hull in 2004, though retaining the catamaran concept. The decision was prompted by a lack of suitable vessels to convert, the lower costs associated with a new-build, and the need to house sophisticated equipment – such as a dynamic positioning system – in the hull.
In 2007, twenty years after the idea was first conceived, Allseas announced plans to build the Pieter Schelte, a twin-hulled platform installation / decommissioning and pipelay vessel. Named after the offshore pioneer Pieter Schelte (father of Heerema), the design featured a lifting system at its bows for lifting platform topsides up to 48,000 tonnes (53,000 short tons) and a lifting system at its stern for lifting steel jackets up to 25,000 tonnes (28,000 short tons). The design also included pipelay equipment to handle pipe diameters ranging from 15–175 cm (6–68 inches) at water depths exceeding 4,000 m (13,000 ft).
Allseas placed orders for machinery, including generators and thrusters, in 2007, and for the high-tensile steel for the lifting systems in 2008.
After the global financial crisis weakened funding, the company was forced to postpone the building schedule and as a result delayed the awarding of the hull construction contract. Finnish engineering company Deltamarin performed detail engineering in 2009.
Midway through the build, Allseas decided to widen the ship by 6.75 m (22.1 ft) in order to increase the clearance between the bows and the legs of large platforms. As a result, the overall width increased from 117 to 124 m (384 to 407 ft), and the slot width from 52 to 59 m (171 to 194 ft).
Pioneering Spirit departed Daewoo in November 2014 and arrived at the Maasvlakte 2, Port of Rotterdam, for completion and commissioning, on January 8, 2015. After the topside lifting system was installed, she left Rotterdam on 6 August 2016.