Wind propulsion pioneer bound4blue has secured an independent methodology review from ABS for its proprietary Pwind force matrix calculations, validating its advanced CFD and wind-tunnel-tested approach. This landmark verification provides shipowners with a credible, regulation-ready pathway to accelerate compliance and accurately quantify the financial and environmental benefits of eSAIL® installations under EEDI, EEXI, and FuelEU Maritime frameworks.
Barcelona | July 2, 2026 – Wind propulsion pioneer bound4blue has secured a major regulatory milestone, obtaining an independent review from the American Bureau of Shipping (ABS) for its proprietary force matrix methodology. The approval focuses on how the company calculates Pwind values, the critical metric used to quantify the effective power contribution of wind-assisted propulsion systems (WAPS) under international maritime frameworks.
By verifying the computational fluid dynamics (CFD) framework used to generate these values, the ABS review provides shipowners with a standardized, audit-ready pathway to integrate eSAIL® performance into mandatory efficiency indexes and regional emissions accounting.
De-Risking the Wind Business Case
Historically, proving the exact aerodynamic output of a wind propulsion system required protracted, expensive physical testing or full-scale sea trials. bound4blue’s approved methodology bypasses this bottleneck by blending advanced Reynolds-Averaged Navier-Stokes (RANS) CFD simulations, wind tunnel data, and potential-based interference analysis.
This computational approach maps out how multiple eSAILs interact with each other and the vessel’s superstructure, creating a highly customized aerodynamic force matrix for individual ships without sacrificing accuracy.
While these matrices do not directly measure dynamic hydrodynamic resistance or day-to-day fuel voyage savings, they serve a more immediate financial and compliance purpose:
- EEDI & EEXI Compliance: Formally lowering a vessel’s certified Energy Efficiency Design Index (EEDI) or Energy Efficiency Existing Ship Index (EEXI).
- FuelEU Maritime Leverage: Providing the mathematically verified foundation needed to claim the Wind Reward Factor, directly reducing a fleet’s compliance penalty exposure under the EU’s tightening greenhouse gas intensity limits.
“In a transitioning and increasingly complex industry, third-party reviews deliver both certainty and transparency for shipowners considering suction sail installations,” said José Miguel Bermúdez, CEO and co-founder of bound4blue. “Independent review from leading Class Societies such as ABS gives stakeholders confidence that the aerodynamic methodology behind our Pwind calculations is robust, credible, and suitable for regulatory use.”
The Aerodynamic Mechanics
The review specifically evaluated how bound4blue generates its aerodynamic polars (lift and drag coefficients across various apparent wind angles).
According to Alberto Llopis, Head of Aerodynamics at bound4blue, the methodology accounts for complex, multi-sail interactions and wake development downstream of the sails. The assessment was conducted in strict accordance with applicable International Maritime Organization (IMO) regulations and International Towing Tank Conference (ITTC) guidelines.
| Phase | Input / Driver | Core Process / Mechanism | Regulatory & Commercial Output |
| 1. Environmental Capture | Wind Flow | Interaction with eSAIL 1 and eSAIL 2 | Raw aerodynamic force generation |
| 2. Interference Mapping | Boundary layer flow | Accounts for downstream Wake Interaction and Sail-to-Sail Interference | Real-world fluid dynamics modeling |
| 3. Analytical Processing | Combined flow field | Synthesis of RANS-CFD simulations and empirical Wind Tunnel Data | Physics-based performance validation |
| 4. Certification | Validated data structures | Compilation into a Verified Pwind Matrix | Independent ABS methodology approval |
| 5. Value Realization | Certified matrix | Integration into statutory ship efficiency calculations | EEDI/EEXI compliance & FuelEU Maritime Wind Rewards |
By validating the underlying process rather than just a single vessel layout, ABS has effectively streamlined the engineering pipeline for future installations. Future eSAIL projects can utilize this approved framework to accelerate project development timelines and class approval phases.
Scaling Up Commercial Traction
The ABS review lands as bound4blue aggressively scales its commercial footprint. The company’s automated, lift-generating suction sails, which utilize a boundary-layer control system to generate forward thrust up to seven times greater than conventional rigid sails of equivalent size, are gaining notable traction in the liquid and dry bulk sectors.
| Parameter | bound4blue eSAIL® Specifications & Track Record |
| Thrust Efficiency | Up to 7 times greater than conventional rigid sails of the same surface area |
| Design Type | Mechanically simplified, non-ATEX units (suitable for hazardous cargo decks) |
| Vessel Versatility | Tankers, bulkers, Ro-Ros, LNG/gas carriers, cruise, and general cargo |
| Current Footprint | 11 ships deployed to date; 7 additional vessels on the order book |
| Total Units Secured | More than 50 eSAILs® ordered or installed globally |
The company’s roster of clients now includes heavyweight operators such as Eastern Pacific Shipping, Maersk Tankers, Odfjell, Klaveness Combination Carriers, and Louis Dreyfus Company (LDC).
As compliance costs under the EU Emissions Trading System (EU ETS) and FuelEU Maritime begin to bite, the ability to present financiers and charterers with an ABS-vetted performance model removes a significant friction point for wind-assisted retrofits.
About bound4blue
bound4blue is a wind propulsion technology company supporting the maritime industry to reduce fuel consumption and emissions. Its eSAIL® system is an automated suction sail that uses wind as a clean energy source to deliver direct thrust to vessels. Founded in 2014, bound4blue is headquartered in Cantabria, Spain, with offices in Barcelona, Singapore, Shanghai, and Suzhou. The company works with shipowners, yards and industry partners across newbuild and retrofit projects. Its client portfolio includes Eastern Pacific Shipping, Maersk Tankers, Odfjell, Klaveness Combination Carriers, BW Epic Kosan and Louis Dreyfus Company, among others.
Source: bound4blue