During the winter transit of the semi-submersible crane vessel (SSCV) Sleipnir, from Rotterdam to New York end of 2025, Heerema Marine Contractors demonstrated how data, technology and offshore expertise can significantly improve both vessel performance and sustainability. In close collaboration with start-up Amphitrite, the team piloted advanced weather routing and voyage optimization, delivering tangible results under challenging North Atlantic conditions.
Following the summer, Heerema and Amphitrite initiated a pilot project to test a machine learning-based routing tool during Sleipnir’s voyage to the United States, where the vessel installed an offshore substation for a large wind farm.
The preparation phase was intensive. Heerema provided five years of historical voyage data, enabling Amphitrite to develop a dedicated Machine Learning model of Sleipnir. This model predicts vessel speed and power consumption under varying environmental conditions and is combined with AI algorithms to optimize routing.
By integrating this vessel-specific model with accurate weather forecasts, the system identifies the most efficient route by making optimal use of wind, waves and ocean currents.
The value of the tool became clear from the start of the journey. During departure from Rozenburg, the system supported decisions on timing and power settings to take advantage of tidal currents in the English Channel.
Further into the North Atlantic, the optimization tool advised a more northerly route to pass above a storm system moving from Greenland towards Europe. This enabled the vessel to benefit from tailwinds while staying close to the great circle route.
While conditions remained demanding – with large waves and vessel motions of up to five degrees – the crew experienced the expected tailwinds, supporting higher speeds and efficient progress across the Atlantic.
On the return trip of Sleipnir from America to Europe a couple of months later, the vessel rerouted to reach the Gulf Stream, and make use of the warm currents moving north-east. The vessel reached an impressive speed over ground of 14.6 knots while “surfing” the Gulf Stream. For a conventional vessel these speed is nothing special, for Sleipnir this is a truly out of the ordinary. Even though the total voyage distance was longer, the increased speed due to the Gulf Stream made the voyage shorter, further illustrating the impact of real-time optimization.
Although direct comparisons at sea are inherently complex, benchmarking against the originally planned route provides a clear indication of the gains achieved: For the voyage from Europe to America:
240 nautical miles shorter route
2.5 days reduction in voyage duration
14–18% reduction in CO₂ emissions
Higher average speeds without increasing fuel use
These results highlight how advanced routing can translate directly into operational efficiency and emissions reduction.
Reflecting on the pilot, Captain Willem van Herwaarden notes the practical value onboard:
“It’s a huge help in the transition from making choices based on weather reports, experience, and gut feeling to making decisions based on accurate environmental forces acting on a dedicated vessel model. This combination of human expertise and advanced analytics ensures that crews remain firmly in control, supported by better insights.”
On another note, Alejandro Velez Isaza, Decarbonization Engineer at Heerema Marine Contractors comments on the other aspects of the succesful collaboration:
“As an offshore contractor we focus so much on understanding how our vessels behave while lifting. The pilot together with Amphitrite is not only a success in routing optimization, but has also brought new insights on how our vessel sails, enabling new opportunities for fuel optimization in this fuel-intensive mode.”
For Heerema, the pilot goes beyond a single successful voyage. It demonstrates how combining in-house expertise with innovative partners can unlock new ways of working.
Every optimization, whether through smarter routing, vessel analytics or performance monitoring, contributes to improving fleet efficiency and reducing emissions. In doing so, we take responsibility for our operational impact and actively support Heerema’s broader decarbonization ambitions.
The collaboration with Amphitrite underlines the strength of teamwork, working as one with forward-looking partners to accelerate innovation and deliver better outcomes for our operations and the environment.