Page 19: of Maritime Reporter Magazine (February 2026)

can support selective activation. Operating pressures, diam- eters, and jet incidence angles can be tuned to balance power consumption and air-sheet characteristics. Current industrial high-pressure waterjet systems demonstrate the feasibility of operating in the required ranges.

Research is ongoing on optimizing nozzle con? guration, pressure tuning, and jet inclination angles. Future work in- cludes physical experiments on hull panels, model testing, scaling studies for full-size vessel applications, and sea trials.

Advantages of the Coanda Jet System con? guration: • Retro? t-friendly (external installation) • Low sensitivity to sea state • Multi-regime operational ? exibility • Minimal mechanical complexity • Potentially signi? cant drag reduction

Conclusion

The Coanda-effect jet system represents a new class of hy- drodynamic ? ow-control technology for ships. By combining jet adhesion, natural air entrainment, low-pressure driven air- sheet formation, and multiphase boundary-layer manipula- tion, this concept offers a transformative method for reducing hull friction, representing a major step change in resistance reduction. By decreasing viscous drag and propulsion power demand, the system allows vessels to reduce operational fuel consumption, reduce carbon emissions, improve EEXI mar- gins, meet EEDI targets for new builds, and directly support

IMO carbon-intensity reduction goals. Its simplicity, stability, and retro? t potential distinguish it from existing air lubrication solutions. The technology offers a promising pathway toward measurable drag reduction and compliance with IMO decar- bonization requirements. In addition, the system can be used to necessarily achieve higher vessel speeds when ? tted to the existing vessel using the same amount of propulsion power.

References

System and Method for Reducing Drag on the Hull of a

Vessel, US patent US 12,280,854 B2, 2024.

The Authors

Hussain

Mohamed Hussain, PhD, PE, specializes in marine hydrodynamics, multiphase CFD, and innovative energy-saving concepts, with a focus on reducing hull drag and improving energy ef- ? ciency solutions for the shipping industry.

Karmous

Kal Karmous is a mechanical engineer with a BSc in

Mechanical Engineering from North Carolina State

University and over 30 years of experience in oil and gas drilling operations, now focused on developing and advancing practical engineering inventions. Con- nect with Kal at [email protected]

MR #2 (18-33).indd 19 MR #2 (18-33).indd 19 2/5/2026 6:59:59 PM2/5/2026 6:59:59 PM