Pioneering Spirit

The initial concept, by Allseas technical director W.P. Kaldenbach, 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. Named after the offshore pioneer , the father of Allseas' owner Edward Heerema, the design featured a lifting system at its bows for lifting platform topsides up to and a lifting system at its stern for lifting steel jackets up to . The design also included pipelay equipment to handle pipe diameters ranging from at water depths exceeding . Construction Allseas placed orders for machinery, including generators and thrusters, in 2007, and for the high-tensile steel for the lifting systems in 2008. After funding became scarce during the 2008 financial crisis, the company postponed the building schedule and delayed awarding the hull construction contract. Finnish engineering company Deltamarin performed detail engineering in 2009. Allseas eventually was able to sign the main construction contract in June 2010 with South Korean shipyard Daewoo Shipbuilding & Marine Engineering Co Ltd. Midway through the build, Allseas decided to widen the ship by in order to increase the clearance between the bows and the legs of large platforms. As a result, the overall width increased from , and the slot width from . 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. The original name caused controversy due to Pieter Schelte Heerema's service in the Waffen-SS during World War II. As a result, in February 2015, Allseas announced that the vessel's name would be changed to Pioneering Spirit. Upgrades In July 2019, Allseas announced a plan to upgrade the lift capacity from 48,000 tonnes to 60,000 tonnes to enable the removal of Statfjord A platform in the North Sea. In September 2021, a set of shear legs with a lifting capacity of 20,000 tonnes was installed on the stern deck of the ship, permitting it to also hoist platform jackets. This also made it the largest floating sheerleg in the world. ==Design==

File:Pioneering Spirit (ship, 2014) 007.jpg|Carrying a test platform in the bow slot (Aug 2016) File:Pioneering Spirit vertrekt vanaf Maasvlakte 2 naar de Noordzee 6-8-2016 (28693743602).jpg|Six lifting beams, retracted (Jun 2016) File:PIONEERING SPIRIT (50291262853).jpg|The Huisman crane is mounted in a tub on the port side of the stern (Aug 2020) Pioneering Spirit is the world's largest vessel, in terms of her gross tonnage (403,342 gt), breadth (), and displacement (). Topside installation and decommissioning operations on Pioneering Spirit rely on advanced structural engineering and heavy‑lift engineering practices to manage extreme loads, motion‑compensated lifting, and precision during single‑lift activities. Aside from the ballast lifting system, Pioneering Spirit is equipped with large conventional cranes, including a sheerleg and rotating cranes. Two tilting lift beams for the installation or removal of the steel jackets used for fixed platforms, up to in weight, will be located at the vessel's stern. The lift beams for the jacket lifting system were installed in 2021. The first major lifts with the new Huisman crane were performed in August 2020. When equipped with the stinger, Pioneering Spirit can be used to lay pipe. Pipe segments are welded together on board the vessel, then are placed on the stinger, where they roll into the water. The stinger is curved to guide the pipe to the bottom of the ocean. The stinger itself weighs and measures long and wide. It is attached to the stinger transition frame (STF), which provides an interface between the stinger and the vessel; the STF is installed in the bow slot when attached to the vessel. The stinger transition frame weighs more than by itself. The vessel is equipped with eight, 20-cylinder (20V32/44CR) MAN 11,200 kW diesel generators providing a total installed power of 95 MW, driving 12 Rolls-Royce azimuth thrusters which provide dynamic positioning (DP3) and propulsion. The vessel's maximum speed is . The accommodation has room for 571 persons in two-berth cabins. ==Projects==

Pioneering Spirit performed her first commercial lift, removal of Repsol's Yme mobile offshore production unit (MOPU) on 22 August 2016. Located in the Yme field in the Norwegian sector of the North Sea, approximately west of Stavanger, the MOPU was a jack-up type platform standing on three, diameter steel legs. The decision to remove the platform was made in 2013, and the contract for the removal of the topsides was subsequently awarded to Allseas. Pioneering Spirit collided with the caisson of the Yme platform during the removal. On 28 April 2017 Pioneering Spirit performed the single-lift removal of Shell's Brent Delta topsides. Located in the Brent field, approximately off the northeast coast of Shetland, the iconic platform sat on a three-legged gravity-based structure in of water. The vessel delivered the topsides to Able UK's Seaton Port yard, Teesside, for disposal. Pioneering Spirit installed the offshore section of SouthStream Transport B.V's dual Turkish Stream pipeline in the Black Sea. The pipeline construction started in May 2017 and was completed in November 2018. Starting from the Russian coast near the town of Anapa, the , diameter twin-pipeline will traverse the Black Sea at depths up to and emerge onshore in Turkey's Thrace region. She has installed three out of four platform topsides for phase one of the Johan Sverdrup development in offshore Norway. The drilling platform (DP) topside was installed in June 2018. The other two topsides named P1 and LQ were installed in March 2019. With P1 topside weighing 26,000 tons, this is one of the heaviest single-lift executed offshore to date, after Wheatstone of 36,000 ton and Arkutun Dagi of 42,380 ton, both with the H 851. The vessel is expected to return in 2022 to install P2 topside weighing 27,000 tons for phase two of the Johan Sverdrup development. It removed Valhall QP topside for Aker BP in June 2019. This structure was an accommodation platform in the Valhall oil field, located in the southern part of the North Sea about 280 km off the Norwegian coast. Weighing 3800 ton, it is the lightest lift operation performed by the vessel. In June 2019, Pioneering Spirit also removed the Brent Bravo 25,000-tonne topside located 186 km off the coast of Scotland on the way to Norway. By 2024 the vessel had removed all of the Brent topsides, culminating with a world-record offshore lift of 31,000 tonnes at Brent Charlie in July of that year. In 2025 Pioneering Spirit delivered the converter platform BorWin Epsilon to the windfarm He Dreiht in the north sea. == Future designs ==

In 2018, Allseas announced its intention to build an even larger version of Pioneering Spirit, named Amazing Grace, scheduled to be delivered in 2022. However, in July 2020, Allseas announced that it would suspend the project indefinitely. == References ==