As a result, attaining a sufficient safety level through opera-tional measures is linked with various aspects of the vessel (hull shape, ship handling, subpision, cargo handling, systems design, etc。), with different phases of the vessel’s life (from concept design to actual operation at sea), and with different stakeholders (ship officers, ship owner, cargo owner, shipyards and designers, class, administration)。

It can therefore be understood that the concept of “ship sta-bility and safety through operational measures” embraces a variety of conceptual, theoretical, technical, regulatory and educational challenges, calling for associated research and development efforts。 The combination of passive design measures with active operational measures can therefore represent a virtuous holistic approach for increasing, in a cost-effective way, the overall level of safety of the vessel, and this concept is further elaborated in this paper with specific attention to the intact condition。

Present intact stability IMO/SOLAS regulations and class rules are mostly “design oriented” and based on an implicit “passive safety” concept, giving a limited attention to operational aspects, often in the form of qualitative, more than quantitative, indica-tions。 As a result, operational measures aimed at increasing the overall safety level of the vessel are put in place by ship owners and operators on the basis of a mostly voluntary, and not har-monised, approach。

This situation, where operational safety measures are neither facilitated nor sufficiently normed by the regulators, does not promote the implementation of approaches aimed at increasing safety through proper and cost-effective operational measures。 The eventual result is a lack of promotion of holistic approaches to safety, with consequent missing of opportunities for a potential increase of the fleet safety level。

An example of what the shipping system is possibly missing in terms of potential increase of safety can be found by looking at the experience from a European PCTC operator (Huss, 2014; Ovegård et al。, 2012; Söder et al。, 2012, 2013)。 In such case, the occurrence of large amplitude motions, associated with phenomena driven by variations of restoring moment in waves, have been significantly decreased by implementing a holistic pro-active framework including a chain of activities: design optimisation to ascertain ships’ hull forms which are sufficiently robust for their intended service (using extensive numerical simulations and model experiments); continuous recording of ship motions and wave measurements with associated analysis and follow up (particularly in case of occurrence of dangerous events); education of all officers (with particular reference to the dangerous phenomena the vessel can be prone to); and onboard installation of operational guidance systems。 As can be noticed, such activities embrace all the phases of the life of the vessel, and are targeting the vessel design, the vessel operation, and the education of the crew。 The imple-mentation of such a framework was eventually successful, leading to a reduction of parametric rolling events to a very low rate。

There are therefore many opportunities for research and development associated with the idea of giving a more systematic and quantifiable importance to operational measures。 At the same

time, however, there are also numerous challenges。 Originally prepared as a contribution in support of a workshop organised at the 12th International Conference on Stability of Ships and Ocean Vehicles (STAB2015), and herein extended and revised, this paper therefore aims at capturing recent trends of research targeting operational safety measures in intact condition。 Furthermore, the paper discusses potential benefits and shortcomings of different possible options and explores needs and possibilities for further developments in this area。 In this context, some ideas regarding opportunities and open challenges have been collected in the following, where the discussion is split in three sections, namely: design, regulatory and classification aspects; tools and methodol-ogies; implementation in operation。 However, a sharp separation proved to be very difficult since several of the given considerations are actually conceptually spanning more than one, and in some cases, all the three sections。 As a result, some topics appear in more than one section taking, however, a different flavour depending on the perspective they are looked from。