Iperen Direkci discusses the first yacht specific, internationally developed method to assess and compare environmental performance on a consistent and credible basis
With publication now imminent, ISO/TS 23099 marks a major step for the large yacht sector within our industry. The International Organization for Standardization (ISO)has approved ISO/TS 23099, a Technical Specification developed under ISO Technical Committee 8, Subcommittee 12 for large yachts.
The work builds on the outcomes of the Yacht Environmental Transparency Index (YETI) Joint Industry Project, led by Water Revolution Foundation, and reflects several years of collaboration between shipyards, naval architects, technical experts, research institutes and classification societies.
That matters because environmental claims in yachting have too often lacked a common reference point. It is easy to talk about greener design, lower impact or improved efficiency. It is much harder to compare yachts on a fair basis using a method that is transparent, repeatable and tailored to how large yachts actually operate. ISO/TS 23099 is important precisely because it starts to solve that problem.
National standardization bodies representing major yacht-building nations, including Italy, the Netherlands, Germany, Turkey, Poland, the United Kingdom and the United States, supported the approval of the specification. It is also the first project delivered by ISO TC8 SC12 Working Group 6 on Large Yachts Sustainability & Environment, which signals that this is not a one-off exercise but part of a broader effort to create more robust environmental references for the sector.
At its core, ISO/TS 23099 provides a methodology for yachts of 30 metres and above to be assessed on environmental performance, compared across the fleet and rated according to defined formulas and criteria. In plain terms, it creates a common framework for measuring what has previously been discussed in far vaguer language.
One of the strongest aspects of the method is that it is built around a yacht-specific operational profile rather than borrowed assumptions from commercial shipping. That distinction is critical. Large yachts do not operate like merchant vessels. They spend significant time not only cruising, but also at anchor and in port, where hotel loads and onboard systems continue to drive energy demand and emissions. A methodology that ignores that reality would miss much of the picture. ISO/TS 23099 does not.
This also makes the specification relevant well beyond design offices. For yacht managers, it offers a more credible basis for evaluating environmental performance and comparing options during refit planning or operational review. For captains and senior crew, it reinforces the importance of energy use while alongside or at anchor, not just underway. For shipyards and designers, it provides a structure for testing whether proposed solutions actually improve performance in measurable terms rather than simply sounding impressive in a brochure.
Another strength is that the method does not stop at a single headline carbon figure. It is intended to support a broader environmental assessment, helping identify which aspects of a yacht’s profile are driving impact and where meaningful improvements can be made. A credible assessment method is not only about producing a score. It is about enabling better decisions.
There is also a strategic point here. ISO/TS 23099 is a Technical Specification, not yet a full International Standard meaning that the method is ready for use but still expected to evolve through application, feedback and further validation. In practical terms, publication is not the end of the job. The more it is being used and tested the more fair it becomes for future.
