Spring Marine, a leading Greek ship management company, first introduced Sulnox Eco on selected vessels in 2023 and subsequently conducted a two-year evaluation programme using Coriolis mass flow meters, torque meters and engine performance monitoring systems.
The evaluation recorded average fuel consumption reductions of approximately 5%, and on vessels where monitoring conditions permitted full specific fuel oil consumption (SFOC) analysis - one of the most rigorous measures of combustion efficiency - improvements of 3.6% to 5.9% were recorded.
Following the successful evaluation, Spring Marine approved fleet-wide rollout. The initiative is estimated to reduce annual CO₂ emissions by approximately 23,000 tonnes, while also supporting improvements in Energy Efficiency Operational Indicator (EEOI) and Carbon Intensity Indicator (CII) performance.
Operational benefits reported by onboard crews included:
Cleaner combustion components with reduced carbon build-up on piston crowns, rings and grooves
Injectors remaining clean and in good condition
Purifiers operating efficiently with minimal sludge
Consistently clean exhaust emissions with no visible black smoke
These results led to Spring Marine winning the "Industry Partnership Leader Award – Bronze" at the 2026 ESG Shipping Awards.
In announcing the award, the judging panel highlighted:
Fleet-wide rollout of Sulnox Eco across Spring Marine vessels
Measurable fuel consumption reductions averaging approximately 5%
Estimated annual reduction of approximately 23,000 tonnes of CO₂ emissions
Improved combustion efficiency and lower visible emissions
Achieved without vessel modification, retrofit or capital expenditure
"Measurable fuel savings, cleaner engine components and lower emissions — all confirmed through onboard monitoring and crew observation, and all delivered through a drop-in solution requiring no capital expenditure or dry docking. We are delighted to see that approach recognised, and look forward to what the next phase of this partnership delivers."
Captain George Chondronikolas, General Manager, Spring Marine
See our extensive results across vessel segments and fuel types - and discover the impact Sulnox Eco could have on your fleet.
