Improvements and updates to Intact Stability Standards applied to domestic vessels in Australia

摘要

The National Marine Safety Committee has recently revised two standards on intact stability, the first dealing with intact stability criteria, the second with stability tests and stability information. The revision incorporates a more performance-based structure with lessons learnt from the application of the previous standards over a 25 years period. The standard on intact stability criteria has been formulated to widen options for compliance by distinguishing between so-called comprehensive and simplified criteria; and between criteria of general application and criteria for special operations. As an example of the last of these, there are criteria for vessels engaged in towing rather than being applicable to just tugs. Likewise there are criteria for vessels engaged in trawling rather than being limited to trawlers. Significant changes have been made to ensure simplified and comprehensive criteria provide similar safety outcomes; for example heeling moments are now directly comparable. A more performance based approach has been taken for determining the maximum allowable angle of heel resulting from a static heeling moment. A major change has been a significant increase in the minimum assumed mass of persons to take into account the changing demographic characteristics of the Australian population and serious incidents that occurred in the USA. The standard for stability tests and stability information has also been significantly revised. It has replaced discretionary clauses with specified criteria for the application of inclining experiments, lightship measurements, simplified stability tests, draft markings, stability books, abbreviated stability calculation methods and other forms of stability information. Procedures for inclining experiments and other stability tests have been revised to comply with standard experimental procedure. Both standards have been prepared with significant input from both government and industry stakeholders.