Section 3 Materials

3.1.1 The materials used for major structural and machinery components are to be manufactured and tested in accordance with the requirements of the Rules for the Manufacture, Testing and Certification of Materials, July 2022 (hereinafter referred to as the Rules for Materials). These components include hull support structure, pod body, pod strut, shafting and propellers.

3.1.2 Components of novel design or components manufactured from materials not covered by the Rules for the Manufacture, Testing and Certification of Materials, July 2022 are to be subject to evaluation and approval by Lloyd’s Register (hereinafter referred to as ‘LR’) prior to manufacture.

3.1.3 Material specifications, see Pt 5, Ch 9, 2.2 Plans and information to be submitted 2.2.1.(f), for propulsion shaft and slewing ring bearings, gearing and couplings are to be approved by LR prior to manufacture. The specification is to include details of the grade of material, including the target range of chemical composition that is to be reported on the certificate, the required mechanical properties, heat treatment details including temperatures and hold times, details of necessary non-destructive examinations including acceptance levels. Additionally, any steel cleanness or microstructure requirements are to be included. These components are to be manufactured under survey.

3.1.4 For propulsion shaft rolling element bearings, the amount of retained austenite is to be determined and is not to exceed 4 per cent for nominally bainitic structures.

3.1.5 Where load carrying threaded fasteners screw directly into structural castings, the integrity of the casting is to be such that there is no porosity or shrinkage in the area of the connection.