Risk based rulemaking and design - Proceed with caution

The trend towards a risk based regulatory framework at IMO and within classification societies is expanding while some voices claim that a full ship risk based scantlings design approach can be immediately implementable. This paper attempts to clarify some widely used, but confusing to many, notions such as Risk Based Rulemaking vs. Risk Based Design, and IMO's Goal Based Standards Traditional Approach vs. Safety Level Approach, and the implications of their use, or misuse, to future ship rulemaking, design and safety. The paper elaborates on some identified weaknesses of Formal Safety Assessment and the risk based approach which must be corrected. It further cautions on the over eagerness of some rule makers and designers to drop all prescriptive rule formulations and haphazardly adopt risk based formulations borrowed from other industries which may not be appropriate for ships. A reliable risk based approach involves avoidance to cut corners and thus avoidance on relying on a large number of arbitrary assumptions. To be applied properly, the risk based approach requires a significant amount of future research in order to reliably link from first principles the ship risk model with the desired acceptable Risk or Safety level.