Lloyd’s Register (LR) has granted Approval in Principle (AiP) to Dutch firm Rondal for its Aero Wing Sail, following completion of concept-level assessment work in line with LR’s 2025 Guidance Notes on Wind Assisted Propulsion Systems.
The Aero Wing Sail is a rigid wing-sail concept developed for large yachts and multihull vessels, designed to provide wind-assisted propulsion while allowing easier integration into vessel layouts.
LR said the AiP confirms the concept has been reviewed against key safety, structural, mechanical and aerodynamic requirements. The assessment included Computational Fluid Dynamics (CFD) analysis, structural design review and mechanical system evaluation to identify operational and integration risks, with recommendations provided for further development.
“This Approval in Principle reflects Lloyd’s Register’s commitment to enabling innovative technologies that support decarbonisation and operational efficiency. Wind-assisted propulsion is a vital step toward reducing emissions, and we are proud to collaborate with Rondal in bringing this solution closer to market readiness,” Tom Wolodarsky, Senior Surveyor and Lead Specialist WASP at LR, said.
“This Approval in Principle is an important achievement for Rondal. It demonstrates the maturity of the Aero Wing Sail and that we are ready for application in new yacht projects,” Hermen de Jong, Innovation Manager at Rondal, said.
LR said the AiP forms part of its wider work to support the safe and scalable adoption of wind-assisted propulsion technologies. Further guidance on deployment and retrofitting is covered in the report Applying wind-assisted propulsion to ships, produced as part of LR’s Retrofit Research Programme.
