An assessment is made of the stress distribution and the hydrodynamic response of the preliminary structural design of the tension leg platform of a 10 MW wind turbine. The platform supporting a 10 MW turbine is modelled and analysed by the finite element method. The stress distribution of the platform is determined in still water with the turbine at above-rated conditions, and the response of the tension leg platform is estimated in the time domain. The results of the time domain analysis show reasonable agreement between the present results and the available data. To check the design stiffener dimensions, span, and spacing against stress distribution, classification societies’ recommendations are used. The results of the stress distribution analysis indicate that the critical locations of the platform are the interaction of the lower columns with the upper columns and the connection of the tower of the turbine.

A new uncertainty quantifier is presented for linear transfer functions of wave-induced ship motions and loads obtained by various seakeeping codes. The numerical simulations are conducted for the high-speed Flokstra container ship in regular waves at various heading angles, and the results are compared with existing experimental data. The study employs five numerical codes that are based on three different seakeeping theories, namely strip theory, 3D frequency-domain method, and 3D time-domain method. Multiple measures are applied to quantify the uncertainty in the calculated transfer functions, such as frequency-independent model error, coefficient of determination, and the total difference. In addition, a new measure of uncertainty, termed modified total difference, is proposed for determining the uncertainty of individual seakeeping codes based on experimental data rather than the mean of results obtained by numerical codes. Results show that the uncertainty measures can identify differences between the codes. The predicted wave-induced loads have higher uncertainties compared to motions. The uncertainty assessment shows that none of the applied codes can produce accurate estimates for all wave-induced motions and loads at all heading angles at the same time.

A comparative study is presented on ship hull resistance and propulsion power prediction using empirical formulations and a Computational Fluid Dynamics (CFD) based solution. The paper studies three benchmark ship hull models, two containers (KCS and DTC) and a tanker (KVLCC2) ship, using the commercial numerical tool, NavCad, and the open source CFD toolkit, OpenFOAM. Since experimental data for ship resistance are mostly available in model scale, validation of full-scale results generated using empirical formulations and CFD becomes difficult. Thus, model scale CFD simulation results were initially validated against the available experimental data in literature. Then, the CFD results were extrapolated to full scale for comparison with three methods based on different empirical formulations namely, series 60, Holtrop and Andersen. The results show reasonable agreement between NavCad and OpenFOAM results, indicating that in these cases NavCad simplified procedures yield sufficiently accurate results for different ship models with a substantially less effort and computational resource requirement than CFD models.