ABSTRACT
Modern classification rules, that are used to assess the safety of hull structure of ships, are heavily based on direct calculations, i.e. numerical simulations. The range of waves that a ship should withstand, together with the operational profile (speed and heading), is a crucial input to those calculations and is currently provided in the IACS “Rec. No. 34”. This is used as a basis for the designs of almost all of the world’s commercial shipping. IACS has recently undertaken significant work to update this standard to reflect technical advances and knowledge accumulated over the last decades. An updated wave scatter diagram of wave height and period is now proposed, together with a slightly narrower spectral shape and directional spreading. The recommended heading and speed profiles remain mostly the same. This paper presents the technical justification for those changes.
