English

Abstract

SUMMARY This paper outlines challenges in the development of the International Association of Classification Societies (IACS) Common Structural Rules (CSR) for bulk carriers and oil tankers regarding the modeling techniques used and incorporated into the load prediction, structural response and acceptance criteria. The paper also outlines how IACS is responding to the need for consistent implementation and future maintenance of the Rules. As a document that contains rule requirements, a balance had to be made between the incorporation of highly technically advanced methods and practical deterministic application needs, noting that industry has been increasingly calling for the use of advanced predictive models while at the same time asking for a format that will lend itself to quick determinations of initial designs and quick design and building cycles. All the while keeping in mind the main objective; developing Rules that produce safety, robustness and longevity levels expected by society at large. During the criteria development of the CSR a similar balance had to be made in incorporating existing Rule requirements or incorporating risk-based approaches to identify hazards and consequences to concentrate the new rule development attention to the most critical areas. While the CSRs tend to incorporate elements of the existing Class rules and IACS Unified Requirements, it is noted that many areas have been developed or validated using more advanced techniques and employing analysis of hazards and consequences. At the same time the CSRs were being developed, the International Maritime Organization (IMO) were starting to develop broad reaching goal-based standards (GBS) aimed at determining the basic standards used during vessel design. The CSR developers continuously monitored the GBS developments at IMO in order to incorporate pertinent criteria into the CSRs. This paper describes the new relationships which resulted between the classification societies and industry as a consequence of the consultation processes during the development phase. Implementation of CSR by all ten members of IACS represents a step change in the way that IACS functions and the governance requirements of the individual members are satisfied. Also as a result of the CSR implementation, IACS is in a new phase where the CSR rule set has to be maintained. Processes have been established to ensure that the CSR will be maintained effectively, with proper industry consultation. Interpretations and feedback have to be gathered from all IACS members and industry and the response has to be accepted and adopted by all members. Thereafter, there is a program which intends to harmonize the current versions of CSR for oil tankers and bulk carriers to establish a platform for possible future extension into other ship types. NOMENCLATURE