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The SGISC have been developed to account for dangerous dynamic phenomena in waves. Five failure modes are defined, and a multi-layered structure, consisting of vulnerability criteria and Direct Stability Assessment, is adopted to check the ship vulnerability against each phenomenon. If the ship does not comply with one or more criteria, Operational Measures can be provided to reduce the likelihood of stability failures. The present paper provides an overview of Operational Measures and focuses on the application of the Simplified Operational Guidance (OG) for four different ships, each vulnerable to at least one of the failure modes. OG are derived according to IMO Interim Guidelines, by limiting ships’ operation in terms of sailing conditions. The original contribution of this work is the development and application of simple procedures to account for the effect of heading variations, leading to less conservative results in the evaluation of sailing conditions to be avoided. Results are presented in tabular form, reporting the critical speed for which the ship is vulnerable in defined headings, and in polar diagrams, identifying safe sailing conditions for given sea states.

The modelling of planing craft dynamics in waves and related fluid-structure interaction is a hard challenge due to the highly nonlinear, transient and stochastic nature of the whole process. This paper explores the prospectives of detailed experimental modelling of the local structure responses for high-speed planing craft in waves. A novel experimental setup is presented where a well-defined model structure is integrated into the hull bottom of a typical planing craft model. The model is instrumented for measuring strains in the model structure, related slamming pressures, craft rigid body motions and accelerations. The experimental setup is thoroughly described and motivated and crucial aspects of the setup are verified through testing in idealized static loading conditions and by modal analysis. The capabilities of the experimental setup are demonstrated through systematic experiments in regular waves. The most indicative results are presented and discussed in relation to corresponding results from time-domain simulations. The presented experimental modelling approach is concluded to enable uniquely detailed studies of the complete slamming related fluid-structure interaction process and provides a good tool for further research and development towards establishment of first principles-based methods for hydrodynamic and structure design of high-speed planing craft.

A series of hard chine planing hull forms was developed at Department of Naval Architecture, University of Naples. Three warped and one monohedral hulls were designed and four 6 ft long models were built. The models have the same transversal section at 0.25 L from the stern with 16.7 degrees deadrise angle. Warped models had deadrise angle linearly varying along the hull length. Aim of the experimental program is the evaluation of the effect of deadrise angle variation along the hull length on hydrodynamic resistance and on seakeeping although this work presents calm water performances only. The models have clear polycarbonate bottom to allow flow visualization and accurate wetted surface assessment. Resistance tests were performed for speed coefficient CV ranging from 0.56 to 3.92 and for two load coefficient values: CΔ=0.428 and 0.392. Reported results are wetted lengths of pressure area and whisker spray area, projected angles of stagnation line, wetted surface and whisker spray area, residual resistance coefficient, sinkage, presented in standard non-dimensional form, and running trim.