Heerema Marine Contractors and shipbuilder Sembcorp Marine, on Thursday, showed off the world’s largest crane vessel that can be used for the setup and decommissioning of offshore oil and gas facilities, Heerema’s new generation semi-submersible crane vessel: Sleipnir.

The giant crane vessel is equipped with two cranes with a lifting capacity of 10,000 tonnes each. The cranes can reach a height of 220 metres and together can lift loads up to 20,000 tonnes, making it the largest crane vessel in the world. In comparison, Allseas’s decommissioning vessel Pioneering Spirit has a top side lift capacity of 48,000 tonnes using it’s specially designed hydraulic grip system, but its largest crane only has a lift capacity of 5,000 tonnes.

The Sleipnir, named after Norse God Odin’s eight-legged stallion, was built by Sembcorp Marine at its Singapore yard, where it currently sits awaiting final completion and delivery.

“We handle many semi-submersibles, but we never handled such a big size before,” Sembcorp Marine’s CEO Wong Weng Sun told a reporter from Reuters.

Another remarkable feature of the vessel is its capability to run on liquefied natural gas (LNG), making it one of the largest vessels in the world to sail on LNG. The vessel is equipped with 12 dual fuel engines of 8 MW each, divided over four engine rooms. Each engine can run both on marine diesel or LNG. The total power output of the vessels amounts to a staggering 96 MW.

Decommissioning

Heerema intends to use the vessel for all sorts of offshore lifting but is readying the company to enter the decommissioning market as well. The company last week announced the formation of a new decommissioning company called Fairfield Decom, in which it has joined forces with Decom Energy and AF Offshore Decom. Together they create “a unique late-life operations and decommissioning operator, providing an all-encompassing solution for ageing offshore oil and gas assets, primarily in the UK Continental Shelf,” Heerema stated in a press release.

Heerema announced in September last year already that the company, in a consortium with AF Gruppen, had received notice that Fairfield Betula Limited intends to enter into a contract for the removal and disposal of the Dunlin Alpha topside in the UK continental shelf, likely leading to the name of the new entity.

The contract includes Engineering, Preparation, Removal & Disposal (EPRD) of the Dunlin Alpha topside with a total tonnage of approximately 20,000 tonnes, exactly the weight the Sleipnir can lift. The platform is scheduled to be removed and disposed of in the period between 2021 – 2024.

Offshore wind

First Heerema will use the Sleipnir to install the high-voltage substation HKZ Alpha HVAC for Tennet’s Hollandse Kust Zuid offshore wind farm, which is being developed in the North Sea in front of the Dutch coast. 

This contract entails the transport and installation of the HKZ Alpha HVAC platform. The jacket of the platform, weighing 2,800 metric tonnes, will be installed in the second quarter of 2020, with the 3,800 tonnes weighing topside following in the fourth quarter of the year.

For this tender, Heerema used its simulation centre to successfully explore the feasibility to use the Sleipnir in this shallow water location close to shore. 

Heerema Marine Contractors CEO Koos-Jan van Brouwershaven said: “Heerema is very excited to support Petrofac and TenneT in the development of this project in the North Sea. It also gives us the opportunity to contribute to the realization of the Dutch government’s clean energy targets.”

Hollandse Kust Zuid Alpha will go into service in 2021.