ISO15016:2025 Improved Standard for Speed/Power Trials

Creating a level playing field for EEDI, Newbuilding Contracts and EEXI

Speed/power characteristics of ships determine their operational performance, fuel economy and exhaust gas production. Prior to delivery each new ship is subjected to speed/power trials to verify she meets the contractual agreements between owner and yard and (if applicable) that she is compliant with IMO MEPC EEDI regulations. Shaft power and vessel speed over ground are derived from on board measurements. As trials are often conducted in non-ideal conditions, the measurement of the actual environmental conditions and the availability of reliable correction methods for shallow water, wind and waves are essential to achieve the required accuracy. In 2015 IMO MEPC adopted ISO15016:2015 as the standard for the assessment of speed and power for the Energy Efficiency Design Index (EEDI).

Over the last decade important developments in on-board measurements and correction methods have been achieved by the Sea Trial Analysis Group (STA) and by the specialist committees of the International Towing Tanks Conference (ITTC). The recent revision of the ISO standard is based on the foundations of the work of STA and ITTC. The application of correction methods for wind, waves and shallow water have been made consistent while ambiguities are avoided. Measurements of wind and waves have been specified and new limits for allowable weather conditions in relation to ship size have been agreed. The resulting ISO15016:2025 was published in January 2025 and replaces and cancels the 2015 edition. The improved standard offers a practical and more reliable standard for speed/power trials and enables a level playing field for EEDI and new building contract trials as well as for EEXI-trials on existing ships. In this paper the main revisions are presented.