bound4blue Model 3-24 eSAI Receives DNV Type Approval

bound4blue has received Type Approval Design Certification (TADC) from DNV for its Model 3-24 eSAIL, the company’s largest and most powerful installed suction sail. The approval, formally presented during a handover ceremony at last week’s Posidonia in Athens, confirms the system’s compliance with DNV’s classification requirements for safety, structural integrity, and design robustness.

bound4blue’s Model 3 range is designed for larger vessels and projects looking to maximize the possible propulsive contribution from wind power. Units range from 24 meters to 36 meters in height. The Model 3-24 is the first of the new design to be installed, with two units fitted on the DNV classed Klaveness Combination Carriers newbuild MV Baltazar in April. With an expanded sail surface area and optimized aerodynamic profile, the system maximizes lift generation, enabling shipowners to achieve greater fuel savings and emissions reductions across a wide range of vessel types.

Built on bound4blue’s established Model 2 platform, the new 3-24 eSAIL®features a wider chord and increased sail surface area compared to earlier designs. This enables enhanced aerodynamic efficiency and higher propulsion output, while maintaining the system’s ease of integration, with limited additional system complexity, such as tilting mechanisms.

With fully autonomous operation, eSAILs utilize boundary layer suction technology, drawing air across an aerodynamically optimised surface to generate propulsive force and reduce main engine fuel consumption and CO2 emissions. This supports both cost reductions and regulatory compliance, including frameworks such as FuelEU Maritime and the EU Emissions Trading System (EU ETS), as well as contributing directly to Carbon Intensity Indicator (CII) ratings and compliance with EEXI requirements.

As regulations tighten and pressure mounts to reduce emissions, wind propulsion is increasingly used as a solution for both retrofit and newbuild decarbonization strategies.

Designed as a simple, plug-and-play solution, the fully autonomous systems can operate alongside conventional propulsion systems while also supporting the adoption of future fuels such as methanol and ammonia, helping shipowners reduce fuel consumption, emissions, and regulatory exposure.