SSCV Thialf: The Unbelievably Big Crane Ship
The SSCV Thialf is one of the largest and most powerful crane ships in the world. Its full name stands for Semi-Submersible Crane Vessel. It belongs to Heerema Marine Contractors (HMC), a Dutch company known for heavy offshore construction.
The Thialf is not just big, it is a floating giant, capable of lifting entire offshore platforms and wind turbine structures in one piece. It has been working for four decades, yet it remains modern and relevant thanks to continuous upgrades. Even in 2025, it continues to take part in some of the biggest energy projects on earth.
History of SSCV Thialf
The story of the Thialf began in 1985, when it was built in Japan by Mitsui Engineering & Shipbuilding Co. It was originally called DB-102, built as a heavy-lift semi-submersible barge.
In 1997, Heerema Marine Contractors acquired and renamed it Thialf, after a figure from Norse mythology known for great strength. From that moment, the vessel became the pride of the Heerema fleet.
It was designed to perform extremely heavy offshore lifts — tasks that are impossible for ordinary ships. Over the years, Thialf has been used for building and removing oil and gas platforms, installing subsea structures, and, more recently, constructing massive offshore wind farms.
Size of SSCV Thialf
Everything about the Thialf is huge. It is 201.6 meters long and 88.4 meters wide, nearly the length of two football fields placed end to end. The vessel weighs over 136,000 tons when fully loaded.
Thialf has two huge cranes, one on each side of its deck. Each crane can lift thousands of tons, and together, they can lift up to 14,200 metric tons in a single operation. That’s like lifting more than 7,000 family cars at once.
It can carry and accommodate up to 736 people on board, including engineers, operators, divers, and crew members. The ship has cabins, offices, control rooms, workshops, and even a helideck large enough for a heavy-lift helicopter.
How does the SSCV Thialf work?
The Thialf is called a semi-submersible vessel because of its special hull design. It has two large floating pontoons connected to the upper deck by eight vertical columns. When it needs to perform a lift, the vessel takes on seawater into its ballast tanks and sinks lower into the ocean. This lowers the pontoons below the surface, making the ship very stable, even in rough seas.
It also has a Dynamic Positioning (DP) Class III system, which uses six powerful thrusters to hold the ship steady in one position. These thrusters can rotate 360 degrees, automatically adjusting to wind and waves. This precision is vital when lifting and placing massive structures at sea.
When the cranes are ready to lift, operators in control rooms monitor everything down to the centimeter. The cranes slowly raise the load from barges or from the seabed and position it with great accuracy. The Thialf can perform these heavy lifts even in harsh offshore environments such as the North Sea.
Famous Projects Around the World
Since its first mission, Thialf has worked on some of the world’s most famous offshore projects. In 2000, it lifted the 11,883-ton topside of the Shearwater platform in the North Sea, one of the heaviest lifts ever done at that time.
In later years, the ship worked all over the world — from the Gulf of Mexico to the Norwegian Sea. It installed and removed oil and gas platforms, subsea modules, and bridges. But in the last decade, its focus has shifted toward renewable energy projects.
Moving Into the Offshore Wind Era
In recent years, Thialf has become a key player in the offshore wind industry, helping build the foundations for massive wind farms.
In 2023, the vessel worked on the Dogger Bank A and B offshore wind farms in the United Kingdom. It helped install the jacket foundations for the offshore substations, each structure weighing thousands of tons.
In 2024, the Thialf completed a major assignment in the He Dreiht offshore wind farm in Germany, which is the country’s largest offshore wind project. The ship installed 64 monopile foundations, each 70 meters long and weighing around 1,350 tons. It also placed the transition pieces, which connect the monopiles to the turbine towers.
These projects proved that Thialf, even though it was built decades ago, remains one of the most capable offshore construction vessels in the world.
The Historic Baltic Crossing SSCV
A major highlight in Thialf’s career came in 2022, when it crossed under the Storebælt Bridge (Great Belt Bridge) in Denmark to enter the Baltic Sea for the first time.
Because the bridge is very low, the ship had to lower its A-frame crane towers temporarily. The operation was carefully planned and executed, allowing Thialf to reach new markets in the Baltic region for the growing offshore wind sector.
This event showed the flexibility and engineering skill of the Heerema team. After the crossing, Thialf began working in the Baltic Sea on several projects, expanding its reach beyond its traditional North Sea territory.
Upgrading for the Future
Although the Thialf is forty years old, Heerema continues to invest in upgrades to keep it at the cutting edge. In early 2025, the ship received a new motion-compensated pile gripper (MCGF), designed by Ulstein.
This new system allows Thialf to install monopiles up to 12.5 meters in diameter and weighing up to 3,200 tonssome of the largest ever used in offshore wind projects. The gripper keeps the monopile steady, even in waves and wind, ensuring safe and precise installation.
The upgrade prepares Thialf for the next generation of giant offshore wind turbines, which require even bigger and heavier foundations.
Crossing the Atlantic
After finishing its European projects, Thialf crossed the Atlantic Ocean in spring 2025. It arrived in Narragansett Bay, Rhode Island, USA, in May 2025, to support the Empire Wind 1 project, one of the first large-scale offshore wind farms in the United States.
According to recent tracking data (AIS), the vessel was last reported off the U.S. East Coast at around 41.0° N, 71.3° W, with the status “restricted in ability to maneuver” meaning it was working on site.
This move marks a major milestone for both Heerema and Thialf, as they join the emerging American offshore wind market. The ship’s presence in U.S. waters shows how important global cooperation has become for clean energy projects.
Life on Board
Working on the SSCV Thialf is like living in a small floating city. The ship can house over 700 people, each with their own job. Crew members include crane operators, welders, engineers, safety officers, cooks, and marine specialists.
Inside the ship are cabins, dining areas, gyms, and recreational rooms. There are also offices, workshops, and control centers where engineers plan every operation. Because the Thialf often stays offshore for months at a time, life on board is designed to be as comfortable and safe as possible.
A helipad allows helicopters to bring in crew and supplies, while smaller boats deliver equipment and materials. The vessel follows strict safety and environmental rules, as every lift and movement must be carefully controlled.
Challenges and Innovation
Operating such a massive vessel comes with challenges. Heavy-lift operations depend heavily on weather and sea conditions. Strong waves and winds can delay or limit lifts. The ship uses its semi-submersible design and dynamic positioning system to reduce motion, but timing remains crucial.
Another challenge is the transition from fossil fuels to renewable energy. Many of Thialf’s earlier projects were in the oil and gas sector. Now, most new work involves wind energy. This change requires different equipment, training, and planning, but Heerema has managed the shift successfully.
The Thialf is no longer the world’s largest crane vessel, that title now belongs to Heerema’s newer ship, the SSCV Sleipnir, which entered service in 2019 with a lifting capacity of 20,000 tons. Yet Thialf remains one of the most trusted and flexible heavy-lift vessels in the world.
Why SSCV Thialf Matter?
The SSCV Thialf is more than just a big ship. It represents human engineering at its best. It shows what can happen when technology, teamwork, and creativity come together to solve impossible challenges.
From oil platforms in the North Sea to wind farms in the U.S., Thialf has helped build the energy infrastructure that powers modern life. It has adapted to new technologies, new industries, and new environmental standards.
It also plays a symbolic role: showing that older, proven equipment can be updated for a greener future instead of being retired. The fact that a ship built in 1985 is still vital to renewable energy in 2025 is a testament to good design and smart management.
The Future of SSCV
Looking ahead, the SSCV Thialf will likely continue working in both Europe and North America on offshore wind projects. Its new motion-compensated pile gripper allows it to take part in the next generation of large wind farms planned for the North Sea, the Baltic, and the U.S. Atlantic coast.
Heerema Marine Contractors has made sustainability a key focus, and Thialf plays a part in this strategy. The vessel operates under strict emission-control measures, and the company is exploring the use of cleaner fuels to reduce its carbon footprint.
Even as new ships enter the fleet, Thialf will remain one of the most experienced and capable heavy-lift vessels ever built.
Conclusion
The SSCV Thialf is truly an unbelievably big crane ship, a floating legend that continues to shape the world’s energy future.
From its birth in 1985 as DB-102 to its life today as a modern heavy-lift champion, the Thialf has proven that great engineering can stand the test of time. It has lifted some of the world’s heaviest structures, crossed oceans, and adapted to serve a cleaner, greener planet.
As of 2025, the Thialf sails proudly under the Dutch flag, currently working off the U.S. coast for the Empire Wind 1 project, helping build the foundations of a new era in offshore renewable energy.
It remains a symbol of strength, precision, and innovation, a giant of the seas that continues to remind us just how far human ingenuity can go.
