Americans got a pretty good look at the Thialf last year, when the giant crane ship dropped anchor in Narragansett Bay ahead of foundation work at Equinor’s Empire Wind site and briefly became Rhode Island’s favorite thing to photograph. Now the same ship’s wrapped up a bigger version of that job on the other side of the Atlantic, for the same client, and I want to walk you through the pace it kept, because there’s a number buried in it that I really like.<\/p>\n
Heerema Marine Contractors said on September 2<\/a> that the Thialf has finished installing all 100 wind turbine foundations, plus two substation jackets, at the Ba\u0142tyk 2 and Ba\u0142tyk 3 wind farms in the Baltic Sea, 14 to 23 miles off Poland’s coast near the towns of Ustka and \u0141eba. The whole campaign took four months, and Heerema says that’s comfortably inside the schedule it promised. The farms are being developed by Equinor and Polish energy company Polenergia, and together they’ll be one of the largest offshore wind projects Poland has ever built.<\/p>\n A monopile is pretty much what it sounds like: one enormous steel tube, hammered straight down into the seabed until it stays put. The ones at Ba\u0142tyk run 164 to 230 feet long, per Heerema<\/a>. Once a monopile is in, a bright yellow transition piece about 56 feet tall gets set on top, and that’s the collar the turbine tower eventually bolts to. If you’ve ever seen a photo of an offshore wind farm under construction, the yellow rings you see poking out of the water are these.<\/p>\n The Thialf lifts each monopile off a heavy transport vessel lying alongside, swings it from horizontal to vertical, and lowers it to the seabed, while a motion-compensated gripper frame on the ship’s port side holds the tube steady against the swell all the way through pile driving. We’ve covered the hydraulic hammers that do this kind of driving<\/a>, and it’s not gentle work. Doing it a hundred times in a row without wrecking the schedule is the harder trick.<\/p>\n The ship pulling this off is, for my money, the best character in the story.<\/p>\n The Thialf is a semi-submersible, which basically means it’s built to flood its own ballast tanks and ride deeper in the water. Sitting lower makes a platform 289 feet wide steady enough for precision work while the Baltic does whatever it wants around it. The ship runs more than 656 feet long and carries two cranes rated at 7,826 short tons (7,100 metric tons) each. It’s a lot of boat.<\/p>\n It’s also been afloat since 1985, and it held the title of world’s largest crane vessel for over three decades, until Heerema built the Sleipnir and took the crown off its own ship. We’ve written about the world’s heaviest ship<\/a>, which lifts entire oil platforms without a conventional crane, and the Thialf is arguably the closest thing to it that still works the old-fashioned way, with hooks.<\/p>\n Carefully, and after some welding. To sail in from the North Sea, a vessel this tall has to clear Denmark’s Great Belt Bridge, which gives you about 213 feet of air. The tops of the Thialf’s crane frames sit around 344 feet above the water. So Heerema rebuilt the frames with hinged corners that let the cranes fold down, a modification that took about 165 short tons of new steel, The Maritime Executive reported<\/a>. Ballasted down as deep as it would go, the ship just squeaked under the bridge. I’d have paid to watch.<\/p>\n Heerema hasn’t published exact start and finish dates for the run, or a weight for these particular monopiles, which is the kind of figure I usually get to hang a comparison on. What it’s said is that the first 23 foundations were in place by the end of May and the campaign ran four months. So I did the math. Call it roughly 120 days for 100 foundations, and one went in about every day and a quarter. That includes weather days. For a sequence that involves lifting, upending, driving and bolting in open water, that’s a pretty wild rhythm to sustain.<\/p>\n It also wasn’t one ship doing it alone. At the peak, Heerema had about 15 vessels working the site at once, out of roughly 35 support vessels across the campaign: heavy transport ships shuttling monopiles out from port, noise mitigation vessels, crew transfer boats, and teams handling grouting and bolting behind the main ship. Sif and Smulders built the monopiles and transition pieces themselves.<\/p>\n The foundations are the half of a wind farm you’ll never see again. The visible half comes next: 100 Siemens Gamesa turbines rated at 14.4 megawatts each, the SG 14-236 DD model according to offshoreWIND.biz<\/a>. They’re scheduled to start going up in 2027, and the developers say each machine’s going to stand roughly 850 feet tall, which strikes me as a genuinely silly height for something with moving parts. We’ve also covered another giant crane wrestling steel tubes into the seabed for a German wind farm<\/a>, so this corner of the Baltic is getting pretty crowded with machines like these.<\/p>\n Heerema says it’ll be back this winter to set the topside on the Ba\u0142tyk 2 substation, with the Ba\u0142tyk 3 topside scheduled for summer 2027. First power from Ba\u0142tyk 2 and 3 is due on the Polish grid in 2027, and the full 1.44 gigawatts, enough for about two million homes, should be running by 2028.<\/p>\n","protected":false},"excerpt":{"rendered":" Americans got a pretty good look at the Thialf last year, when the giant crane ship dropped anchor in Narragansett … <\/p>\nSo what did it actually put in the water?<\/h2>\n
Only one crane vessel out there is bigger<\/h2>\n
So how do you get a ship like this into the Baltic?<\/h2>\n
One foundation every day and a quarter, give or take<\/h2>\n
The turbines are the 2027 job<\/h2>\n