This part of ISO 12215 specifies requirements for core materials for structural use and materials that are embedded in sandwich construction. It is applicable to small craft with a hull length (LH ) according to ISO 8666 of up to 24 m. NOTE The underlying reason for preparing this part of ISO 12215 is that sandwich structures of small craft require careful selection of core materials from a multitude of choices, and that the manufacturing has to follow certain procedures to achieve the intended long-term durability under the expected loads and environmental conditions.