Rock solid challenges: How jack-ups are adapting to tougher seabeds

As offshore wind expands into new frontiers, jack-up vessels face increasingly difficult working environments. Beyond the sandy soils of the North Sea, projects are now being built on dense tills, coral limestone, and even exposed bedrock. These hard seabeds are testing the limits of conventional jack-up design and installation practices — and calling for new approaches in engineering, simulation, and digital operations.

The global growth of offshore wind is pushing development into regions with very different seabed conditions. From the North Atlantic and the Mediterranean to Asia-Pacific and Australia, new sites promise vast renewable energy potential — but beneath the waves, conditions grow more complex.

Hard or uneven seabeds, combined with greater water depths and long-period swells, introduce challenges. Successful installation and operation in these areas demand a deep understanding of how jack-ups interact with the ground beneath them. For companies like GustoMSC, long recognized for jack-up design and engineering expertise, this evolution is an opportunity to help the industry adapt safely and efficiently to new geological realities.

In soft soil, spudcans — the footings at the base of each jack-up leg — penetrate easily, distributing loads over a broad area. On rock or very dense soil, penetration is minimal or nonexistent. When a spudcan first contacts a hard surface, it can create instantaneous peak loads that reverberate through the legs, jacking system, and hull.

These impact loads can lead to overstress or local damage if not carefully managed. Uneven or sloping seabeds add another layer of risk, as partial contact or eccentric loading may trigger sliding. In areas affected by long-period swell waves, the risk of resonant motion further amplifies impact forces during leg touchdown.

To mitigate these effects, jack-ups must operate within tighter environmental limits during installation. Crews need to continuously assess sea states, jacking speeds, and vessel response — a process that requires both experience and reliable engineering guidance.

With minimal penetration, contact pressures are concentrated in smaller areas, increasing local stress on the structure. Once elevated, jack-ups on hard seabeds face another challenge: maintaining stability without the benefit of soil embedment.

The seabed’s ability to resist tilting is reduced, making the vessel more sensitive to environmental loads. In shallow waters, where breaking waves impose strong horizontal forces, the risk of sliding is higher, particularly on smooth rock with low frictional resistance.

Still, hard seabeds offer advantages too: extremely high bearing capacity, eliminating concerns about excessive settlement. And in seismic regions, jack-up on rock foundations typically perform better under earthquake loading due to lower resonance risk.

Mitigating these challenges begins long before a vessel arrives on site. Site-specific soil investigations provide critical data for jack-up operations.

Using these inputs, GustoMSC engineers run advanced time-domain simulations that model the full dynamic behavior of the jack-up, including wave loading, soil response, and structural flexibility. These analyses help define safe operating envelopes, predict impact loads, and assess potential overstress scenarios.

The outputs translate directly into practical offshore guidance: weather and sea-state limits, safe jacking speeds, and operating procedures tailored to each location.

Such site-specific engineering provides the foundation for safer, more predictable operations — particularly when entering new geographic regions with unfamiliar seabed conditions.

Digitalization now plays a pivotal role in connecting engineering models with real-world performance. Onboard sensor systems monitor key parameters during installation, including leg loads, hull motions, and jacking forces.

By comparing live data with pre-simulated models, engineers can verify performance, identify deviations, and refine future designs. Over time, this feedback loop accelerates learning across the industry, improving both safety and efficiency.

GustoMSC’s vision for the future is a fully integrated digital environment where simulation, monitoring, and decision support tools work seamlessly together. This allows operators to visualize and predict loads in real time — enabling faster, data-driven decisions during critical operations.

In some cases, site conditions demand more than operational control — they call for hardware adaptation. Physical measures such as seabed preparation, gravel placement, or customized spudcan geometries can reduce installation risks.

Engineers at GustoMSC have developed and tested alternative spudcan designs that distribute loads more evenly and incorporate features to absorb impact energy during touchdown. Parallel research has refined the dynamic models that simulate complex leg-soil interactions and jacking system responses, improving prediction accuracy and reducing uncertainty.

These design and modeling advances already demonstrate tangible benefits, allowing operators to work safely in areas that would previously have been considered too challenging.

Progress in this area depends on collaboration across the offshore industry. GustoMSC works closely with operators, classification societies, and research institutions to develop best practices and align standards with the realities of operating on hard seabeds.

As offshore wind continues its global expansion, hard soils and rocky seabeds will become a defining feature of the next generation of projects. Lessons learned in Japan, Australia, and the US will help shape future global standards and influence how jack-ups are designed, operated, and certified. This transition marks a new chapter for offshore engineering — one that values adaptability as much as experience. With advances in simulation, digital monitoring, and collaborative development, the industry is proving that even the toughest ground can support a sustainable future.

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