Take a BOW: the eSAIL® impact on CII compliance

With current industry focus firmly fixed on FuelEU Maritime and EU ETS compliance, you’d be forgiven for temporarily losing sight of CII (the IMO’s Carbon Intensity Indicator), another key industry tool aimed at accelerating decarbonisation. But don’t stress… 

Advanced wind assisted propulsion systems (WAPS) deliver advantages that pay powerful dividends across all key efficiency regulations – unlocking CII benefits similar to their compelling FuelEU gains.  

Real-world rewards 

bound4blue is on a mission to communicate the commercial, environmental and regulatory power of WAPS to the industry at large. We’ve just presented a special report and case study, focusing on the chemical tanker BOW OLYMPUS, at the Royal Institution of Naval Architects, showcasing the real-world regulatory impact of our eSAIL® technology on CII ratings. You can download the full report here:

➡️ Download the full report ⬅️

This post will give a high-level overview, illustrating how your vessels can voyage alongside BOW OLYMPUS towards cost-effective CII compliance with eSAILs®. 

Making the grade(s) for CII compliance 

As you probably know, CII applies to all vessels over 5,000 GT, calculating carbon intensity based on annual CO₂ emissions, distance travelled, and cargo capacity. Ships are then rated, from A (most efficient) to E (least efficient), with emission limits growing more stringent from year to year. Those falling into the realms of D and E ratings over three consecutive years need to submit a “plan of corrective actions” to up their grades into the A to C zone. 

 Wind power delivers a natural advantage here. With bound4blue’s DNV Type Approved eSAILs® onboard, vessels can take advantage of proven, readily available and completely zero emission wind propulsion to radically reduce fuel consumption, emissions and operating costs, achieving double digit percentage savings.  

 The BOW OLYMPUS case study translates this promise into reality. 

Data driven insights 

BOW OLYMPUS is a 30,488 GT chemical tanker, operated by Odfjell and constructed in 2019. In 2025 this liquid bulk chemical transporter will set new standards for the segment with the installation of four 22 metre eSAILs®. 

To illustrate the impact of the technology, bound4blue’s team utilised detailed historical data (from 2023) of the vessel’s routes, operational experience, wind and other weather and ocean conditions, feeding the information into an advanced simulation and modelling approach. When combined with our proprietary aerodynamic modelling of the planned eSAILs® (based on the panel method) this unlocked valuable understanding of how the vessel would perform following the installation… and the effect on CII. The results make for riveting reading. 

Significant savings 

Based on the BOW OLYMPUS’ effective days at sea in 2023, bound4blue’s simulation showed a forecasted potential reduction of some 1,616 tons of CO₂ per annum with the four planned eSAILs®. Furthermore, if advanced weather routing is introduced the suction sail technology could enable an average increase in CO₂ reductions of up to 80% (c. 2,908 tons of CO₂). 

So, what does that mean in terms of CII compliance? 

Comparing how the vessel would perform over the coming years with and without the planned retrofit, with a 3% annual reduction in CII limits from 2027 onwards, created a stark picture. With the eSAILs® BOW OLYMPUS would achieve a B rating up to, and including, 2026, with a C rating afterwards. Without, operations from 2024 to 2028 would all be rated C, falling to a D in 2029 and 2030. 

And, it’s worth bearing in mind, these forecasts were made without the introduction of weather routing, which, as previously highlighted, greatly augments eSAIL® impact. 

BIG benefits 

There’s far more to this case study than we can cover here, so do please download the report for all the details. What we can underline, in simple terms, is the HUGE difference eSAILs® make in achieving, and maintaining, CII compliance. 

As more and more leading shipowners and operators are waking up to, eSAILs® drastically reduce fuel consumption and emissions, unlocking both commercial and environmental benefits. In doing so they open up a practical, cost-effective pathway to compliance with a new generation of maritime regulations.  

This is important today and absolutely essential tomorrow, as these regulations* (including CII) grow increasingly stringent over time, penalising underperformers with a sliding scale of penalties. This means vessels scraping by now will not make the grade in the years ahead, leaving ‘wait and see’ shipping companies with a major compliance headache. 

By adopting wind power ahead of the curve you can access strong competitive advantage, future-proofing your assets for the choppy regulatory waters ahead as the drive to decarbonisation gathers pace. 

The BOW OLYMPUS is already one step ahead. Please contact us to find out how your vessels can take a similar route to greener, more cost efficient and CII compliant operations.   

*Although we’ve used this post to underscore the CII benefits of introducing eSAILs® across fleets it’s important to keep the big picture in mind. The propulsive power of wind unlocks myriad advantages, with the significant fuel savings benefitting your bottom line as much as the environment. The cost of compliance for both the EU ETS framework and FuelEU Maritime is greatly reduced too, with improved fuel efficiency (less emissions) enabling ETS benefits, while reducing overall GHG intensity combines with the ‘wind reward factor’ to unlock powerful FuelEU advantages. The incentives to adopt WAPS have never been as attractive as they are now and, in the evolving regulatory landscape, will continue building into the future.  

About the author

Simone Saettone is a Vessel Performance Manager at bound4blue, specializing in optimizing vessel performance using data analytics and predictive modeling. He holds a Double PhD in Ship Hydrodynamics from the Technical University of Denmark and the Norwegian University of Science and Technology, with research focused on improving marine propulsion systems in waves.