Heerema Cuts Sleipnir Atlantic Transit by 2.5 Days With Voyage Optimization

Heerema Marine Contractors has cut the Atlantic transit time of its crane vessel Sleipnir by 2.5 days using Amphitrite's vessel-specific voyage optimization platform. The pilot combined five years of Heerema operational data with high-resolution ocean intelligence to predict the vessel's speed and power consumption under changing weather, wave and current conditions. Applied during a demanding North Atlantic winter crossing to install an offshore wind substation, the approach delivered measurable time savings and reduced emissions during one of the most energy-intensive phases of offshore operations.

 

Background to the Pilot

 

The pilot brought together offshore expertise and specialised routing technology. It combined Heerema's offshore experience with Amphitrite's vessel-specific voyage optimization platform. Heerema supplied five years of operational data to underpin the project. This data was used to develop a model predicting Sleipnir's speed and power consumption. The model accounts for changing weather, wave and ocean current conditions.

The approach differs meaningfully from conventional weather routing. Standard weather routing typically relies on generic vessel assumptions. By contrast, Amphitrite's method combines vessel-specific performance modelling with detailed ocean intelligence. This intelligence includes high-resolution ocean current, wave and weather data. The combination allows routing decisions tailored to the individual vessel's behaviour.

 

The Vessel and Its Voyage

 

Sleipnir is among the largest vessels of its kind in operation. It is one of the world's largest semi-submersible crane vessels. During the pilot, the vessel was mobilising from Rotterdam to New York. Its purpose was to install an offshore wind substation on arrival. This mobilisation formed the setting for testing the optimisation model.

The timing of the voyage created challenging conditions for the trial. North Atlantic winter conditions put the vessel to a demanding test. The crossing involved rapidly changing winds, waves and ocean currents. These volatile conditions provided a rigorous proving ground for the routing model. Success in such an environment offered a strong test of the technology's value.

 

Optimising the Outbound Crossing

 

The system began delivering benefits soon after departure. Shortly after leaving port, it identified the optimal sailing window for the English Channel. This timing allowed the vessel to benefit from favourable tidal currents. Taking advantage of these currents improved the early stages of the voyage. This demonstrated the model's ability to respond to short-term conditions.

The routing adapted as the crossing progressed and weather developed. The system recommended a more northerly route around a developing storm. This adjustment allowed Sleipnir to make use of favourable tailwinds. At the same time, the vessel remained close to the great-circle route. This balance minimised added distance while capturing weather advantages.

 

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Leveraging the Gulf Stream on Return

 

The return crossing highlighted a further advantage of the approach. Rather than following the shortest route, the model directed the vessel toward the Gulf Stream. This meant the vessel covered a greater overall distance. However, the favourable currents increased its speed over ground. The vessel reached 14.6 knots by using these currents to its advantage.

This strategy illustrates the value of dynamic voyage optimisation. Despite the longer route, the overall transit time was reduced. The gain came from exploiting favourable ocean currents rather than minimising distance. This counterintuitive approach demonstrates the sophistication of the routing model. It shows how ocean intelligence can outweigh simple distance considerations.

 

Operational and Environmental Benefits

 

The pilot delivered gains beyond the immediate time savings. It gave Heerema new insights into how Sleipnir performs during transit. The company's decarbonisation engineer described fleet efficiency as fundamental to its strategy. Understanding the vessel's behaviour creates further opportunities to optimise fuel consumption. This is especially valuable during the energy-intensive transit phase of operations.

The collaboration forms part of a wider use of ocean intelligence at Heerema. It draws on Amphitrite's Ocean Bulletin to support crews and operational teams. This intelligence assists with voyage planning and offshore project preparation across the fleet. Amphitrite framed the project as showing the value of vessel-specific modelling. By factoring currents, waves and weather into routing, operators can reduce transit time, fuel use and emissions.