Cranes and boats have never really gotten along. A crane wants the ground under it to hold still, and a boat is a machine whose entire purpose is to move.<\/p>\n
Bolt a big crane onto a hull and every swell that rocks the deck gets multiplied by the length of the boom. A one-degree roll at the waterline becomes several feet of sway at the hook. That’s survivable when you’re lifting shipping containers. It’s a genuine problem when you’re threading a 351-foot blade onto a hub sitting nearly 500 feet above the North Sea.<\/p>\n
Jan De Nul, the Belgian marine contractor, settled the argument with a ship called Voltaire. Its party trick is simple: when it’s time to work, it stops being a ship.<\/p>\n
The Voltaire is the largest offshore jack-up installation vessel ever built<\/a>, delivered from the COSCO shipyard in Nantong, China, in late 2022. It sails to a wind farm site like any other ship, topping out at 11.5 knots, roughly the pace of a fit guy on a bicycle.<\/p>\n Then it parks. Four steel truss legs, each 426 feet long, run down through the hull and keep going until they find the seabed. A high-speed rack-and-pinion jacking system starts climbing those legs, hauling the entire hull up and out of the water.<\/p>\n Once the hull clears the waves, the Voltaire is no longer floating. It is standing. Jan De Nul says the jacking system supports an elevated load of 16,000 metric tons and keeps working in water up to about 260 feet deep. The paperwork still calls it a vessel. The physics call it a small steel island.<\/p>\n And that’s the entire point. Waves can shove a floating hull around no matter how clever its thrusters are, but they can’t do much to four legs planted in the ground. A crane that would be hopeless on a rolling deck suddenly gets surgical. Foundations can go in from floating ships, and a 5,000-ton floating crane is doing exactly that off Germany<\/a> right now, but the delicate top-end work of standing turbines still mostly belongs to machines that cheat like this.<\/p>\n The numbers on this thing read like typos. The main crane is rated at more than 3,000 metric tons, and instead of sitting on a pedestal it wraps around one of the legs, which makes it the largest leg-encircling crane ever built<\/a>, according to Jan De Nul. The crane house alone weighs 1,800 tons. The boom is 459 feet long and adds another 800.<\/p>\n The cargo deck covers about 7,000 square meters, call it 75,000 square feet, which is an NFL field with room to spare. There’s accommodation for around 100 people and a flight deck for a 10-ton helicopter. And with the legs raised and the boom up, Jan De Nul liked to point out during construction that the Voltaire reaches one meter higher than the Eiffel Tower.<\/p>\n Which was true, briefly. The company published that claim in March 2022, and in that same month Paris helicoptered a new radio antenna onto the tower and stretched it from 324 meters to 330. Nobody at the shipyard issued a correction, and honestly, fair enough.<\/p>\n The ship is also unusually clean for a diesel giant. Jan De Nul says it can run on second-generation biodiesel that cuts its fuel carbon footprint by up to 90 percent, while a double exhaust filter strips up to 99 percent of nanoparticles out of the emissions.<\/p>\n The Voltaire’s first job is the biggest one on the market. Dogger Bank is three wind farm phases of 1.2 gigawatts each, sitting 80 to 125 miles off the Yorkshire coast. When all 3.6 gigawatts are spinning, the developers say it will be the world’s largest offshore wind farm, enough for around six million British homes, roughly 5 percent of the UK’s electricity.<\/p>\n Jan De Nul was hired to transport and stand all 277 turbines. These are GE Vernova Haliade-X machines, 853 feet tall<\/a> with 351-foot blades, and the project has long claimed a single rotation can power a home for about two days. The Voltaire set the first one in the summer of 2023, and first power followed that October.<\/p>\n Progress since then has been a grind. SSE, which leads construction, has cited brutal North Sea weather windows plus two separate blade-damage incidents, and a farm once slated for 2026 now finishes in 2027. The 95th and final turbine of phase A went up in February<\/a>, and the ship steamed straight over to Dogger Bank B<\/a>.<\/p>\n Phase B is where it’s parked now, and the pace is relentless. Per the project’s notices to mariners, turbine installation started on February 21 and runs around the clock, 24 hours a day, until roughly the second quarter of 2027. Twenty turbines were up by early June<\/a>, per the operations notices.<\/p>\n Phase C is 87 foundations already planted in the seabed, waiting. Those will carry the uprated 14-megawatt Haliade-X, the first of that variant installed anywhere, so the heaviest hardware is still ahead. The steel underneath has a saga of its own, by the way. All 277 foundations were in place by late 2025, and if you want to see how messy the supply chain for those giant steel tubes<\/a> can get, Britain’s other flagship wind farm is the case study.<\/p>\n Here’s the freshest wrinkle: one giant ship is no longer enough. In April 2025 the project chartered a second jack-up, Seaway7’s Seaway Ventus<\/a>, to start turbine work at the site from mid-2026. Two ships jacking themselves out of the same patch of sea, chasing one deadline.<\/p>\n The logistics shifted too. GE Vernova moved the turbine staging port from Able Seaton in Hartlepool up to the Port of Nigg near Inverness in May, and on August 12 SSE announced the switch is creating up to 180 jobs in the Scottish Highlands. That’s where towers, nacelles and blades get marshaled before the ships collect them for the run offshore.<\/p>\n For a sense of how unusual that fleet depth is, look across the Atlantic. The United States has exactly one American-built jack-up of this class<\/a>, the Charybdis, stacking turbines off Virginia, and nobody has ordered a second. Dogger Bank alone is running two.<\/p>\n The quiet lesson here is that the bottleneck of offshore wind is no longer the turbine. It’s the handful of machines on Earth that can stand one up. Britain signed off on roughly 3 more gigawatts of Dogger Bank South projects in May, and a proposed fourth phase, Dogger Bank D, is already on the drawing board.<\/p>\n All of that steel will need something to lift it. The Voltaire is committed to this one stretch of the North Sea into 2027, working day and night, standing on its own four legs. Whatever gets built after that will be fighting for its calendar.<\/p>\n","protected":false},"excerpt":{"rendered":" Cranes and boats have never really gotten along. A crane wants the ground under it to hold still, and a … <\/p>\nTaller than the Eiffel Tower, briefly<\/h2>\n
Dogger Bank is 277 turbines, and the finish line moved to 2027<\/h2>\n
Reinforcements, and a move to Scotland<\/h2>\n