Damage stability and survivability - 'nailing' passenger ship safety problems

With artefacts on human endeavours at sea dating as far back as 6500 BC, it is mind boggling to think that it was not until 250 BC when the first recorded steps to establish the foundation of naval architecture, floatability and stability, were made by Archimedes. It is even more astonishing that practical pertinence and function of these two very basic principles remained dormant for nearly two millennia after this, before the first attempts to convey the meaning of stability to men of practice took place in the eighteenth century by Hoste and Bouguer. Pertinent regulations, especially after accidents involving water ingress and flooding (through subdivision and damage stability), were introduced even much later. Notably, the first Merchant Shipping Act of 1854 addressed subdivision and led eventually and after heavy loss of life to the adoption of the first internationally agreed system of subdivision in SOLAS 1929 (Safety of Life at Sea), while the first specific criterion on residual static stability standards was introduced at the 1960 SOLAS Convention. This 'tortoise' pace gave way to the steepest learning curve in the history of naval architecture with the introduction of the probabilistic damage stability rules in the late 60s as an alternative to the deterministic requirements. Prompting and motivating the adoption of a more rational approach to damage stability and survivability necessitated the development of appropriate methods, tools and techniques capable of meaningfully addressing the physical phenomena involved. Within 50years, this new impetus has climaxed to the 'zero tolerance' concept of Safe Return to Port, introduced in July 2009, and to an open proclamation by the Secretary of the International Maritime Organization (IMO) that deterministic requirements have no future. More important, the use of a probabilistic framework and of first-principles tools to address ship safety quantitatively and consistently has given rise to aspirations and henceforth capability in identifying and evaluating the key contributors to passenger ship safety. The revelation was plain and clear, namely: damage stability or, more precisely, lack thereof constitutes by far the key risk contributor for passenger ships. Resolving this problem will be equivalent to solving ('nailing') passenger ship safety problems. The author, having played a protagonist role in contemporary developments on damage stability and survivability and having been involved closely in implementing such developments to the design of modern mega-ships, will attempt to provide a succinct account of pertinent developments on damage stability and survivability and demonstrate their implications on passenger ship design and operation.