Regulatory Developments in Structural Keel Design:A Revised ISO 12215-9

Abstract

The design of yacht keel structures is governed by the ISO 12215-9:2012, which is concerned with the loads and scantlings of monohull sailing craft appendages up to 24 m hull length. However, the significant advances in sailing yacht performance, appendages design, materials and manufacturing of the past decade now warrant a revision of this crucial international standard. Consequently, this paper presents the technical background and impending developments in regulatory yacht keel structures. The proposed revisions include (i) a new load case for lateral impact; (ii) compulsory and more stringent fatigue assessment; (iii) enhanced structural arrangements for bolts and backing plates; and (iv) informative guidelines regarding keel installation procedures. This is the first public introduction of the current developments inherent to the forthcoming ISO 12215-9:2025, which aims to support the design and manufacturing of safe and reliable keel structures for sailing yachts. Furthermore, it is envisaged this work may contribute to the development of future guidelines and regulations for the structural design of hydrofoils and internal supporting structure.