Structural Safety of Ships

Abstract

This chapter explores the structural safety of ships, focusing on tankers and bulk carriers, two ship types that have been the subject of structural safety in recent years. The motivating forces behind many of the technical developments that have affected structural design and safety of tankers and bulk carriers over the years are discussed by considering several questions about the economic and regulatory forces, the industry, and the future of structural safety. MARPOL 73 Convention and amendments established the need for segregated ballast tank capacity for new tankers over 73,000 deadweight tons, to be implemented in a phased manner by 1979. The amendments placed a limit on the size of cargo oil tanks, set limits on the oil outflow in the event of a collision or grounding, and set other operational requirements to minimize pollution. Following Oil Pollution Act (OPA)-90 and the requirement for double hull tankers, the regulatory pressure had shifted to a new emphasis on the human element in the marine safety equation. Within International Maritime Organization (IMO), two initiatives were developed. One was the International Safety Management (ISM) Code, which defined a management system approach for the management and operation of all vessels. The other was major revisions to the Convention on Standards of Training, Certification, and Watchkeeping (STCW) of seafarers. Structural safety has been largely reactive, rather than proactive. In some cases, this is necessary because the types of problems encountered are new and unexpected, such as the fatigue problems in very large crude oil carriers (VLCCs).