Speed and power trials and ISO 15016
Speed trial conduct and analysis: ISO 15016:2025, ITTC 7.5-04-01-01.1 (2024), the MEPC.403(83) transition on 1 May 2026, and what the new edition changed.
A speed and power trial establishes the contractual relationship between shaft power and ship speed in a defined condition, and it is the reference curve every later performance assessment is measured against. The analysis standard changed in 2025 and the change is not cosmetic.
ISO 15016:2025, published 3 February 2025, superseded ISO 15016:2015 and was retitled from Guidelines to Specifications. Resolution MEPC.403(83), adopted 11 April 2025, amended the EEDI survey and certification guidelines to require either ISO 15016:2025 or ITTC Recommended Procedure 7.5-04-01-01.1 (2024) for trials conducted from 1 May 2026, with the 2015 edition valid only for earlier trials. The 2024 ITTC procedure supersedes the 2017, 2021 and 2022 revisions.
The 2025 edition made Annex K normative, adopted a different wave correction method, replaced the shallow-water correction, moved the wind profile exponent and tied maximum trial wind speed to ship length. The practical consequence is that reported trial speed generally rises by up to 0.2 knots on the same measured data, so trials analysed under different editions are not directly comparable. The full article will cover trial conduct, the correction chain, and the interaction with ISO 19030 hull and propeller performance and slow steaming .