Design of hulls is typically undertaken on the assumption that the pressures applied are the same as if the hull was rigid. Understanding the effect a flexible structure has on the loads and responses during slamming events will improve the design process for high speed marine craft. In reality the loads may vary due to fluid-structure interaction during the impact. This work characterises the variations in both applied pressure and panel response due to hydroelasticity. Water impacts of flat panels have been undertaken using a purpose built servo-hydraulic slam testing system with impact velocities up to 6.0 m/s and a deadrise angles of 10°. The unsupported panel area was approx. 1000 x 500 mm with simply supported boundaries along all four edges. Clear trends between a panel's flexibility and the total force and applied pressure have been observed. The changes in both loads and responses are largest at the centre and chine edge of the panel. These variations can be related to the significant changes in local velocity (centre) and deadrise angle (chine).

There are many factors critical to the success of a Whitbread Round The World Race™ campaign. One of the most significant is the design, construction, and selection of an individual leg inventory of offwind sails. As a result of the technical challenges to the experimental and computational analysis of offwind sails, shape development for this class of sails has historically relied upon empirical efforts. An added element for any advanced, state-of-the-art, sail development program is the extensive reliance upon wind tunnel results to guide sail shape improvement and leg inventory selection of offwind sails. Lessons regarding improved offwind sail shapes, construction techniques, use of exotic materials, and sail trim learned or reinforced during the 1997-98 Whitbread Round the World Race sail development program for Swedish Match, are described with particular emphasis placed on the role of wind tunnel testing. Current methods for assessing slamming of ships in head seas are generally based on constant-velocity wedge impact results for each hull section. A 2D Smoothed Particle Hydrodynamics (SPH) method is described for calculating slamming loads on realistic hull section shapes and impact velocity profiles. SPH is a particle-based method that is mesh-free and is therefore able to accurately simulate large free surface deformations such as jets and splashes, which are an important factor in slamming events. It is shown that large slamming pressures are predicted on wedge shaped hull sections and the concave part of flared monohull sections. Similarly, cross-deck slamming of catam aran hulls can produce large slamming pressures at the top of the arches. The nature of relative vertical velocity profiles during slam events is also discussed. Hull sections with varying velocity profiles are modelled using SPH to show the effect on slamming pressures as compared to the commonly used constant velocity profile. Slotted Headsail Luff Support System - the development of these systems has proceeded at an extremely rapid rate. Starting with the Sea Stay and proceeding through the Stream Stay, Head Foil, Sail Leda, and Micro Foil, etc. Some of the new systems replace the headstay entirely while others fit on over (around, etc.) the existing headstay. This report establishes a framework for analysing these systems and reports on certain physical features of the more prominent ones. Wind tunnel test results of a winglet keel model are presented. Results including force measurements and wake surveys for several winglet pitch angles and two winglet longitudinal positions are shown. The measured trends as well as the absolute values of the forces and the wake fields can be used for validating CFD codes. An aerodynamic numerical optimisation procedure for an AC72 rigid wing sail was developed. The core of the method is the geometric parameterisation strategy based on a mesh morphing technique. The morphing action, which uses radial basis functions, is integrated within the Reynolds-averaged Navier-Stokes solver and provides an efficient parametric sail aerodynamic nanalysis method which is integrated in an optimisation environment based on a velocity prediction program. A hydrodynamic model is coupled to the parametric numerical solver in an iterative procedure. The shape modifiers operate on angle of attack and twist of nthe fore and aft wing element. For each true wind condition, the velocity of the boat is maximised by iterating between the solution of the velocity prediction program and the solution of the fluid dynamic solver. The effectiveness of the proposed method is demonstrated testing a range of wind speeds.

Smoothed Particle Hydrodynamics (SPH) is a mesh-free Lagrangian computational method suited to modelling fluids with a freely deforming surface. In the present work, SPH has been applied to the problem of slamming, focusing particularly on the impact of two dimensional wedge forms on a free surface contained in a hydrostatic tank. Results from the wedge simulations have shown good agreement with previous experimental studies, paving the way for the work to be extended to mono-hull and catamaran hull forms. The completed validation of the SPH algorithm as applied to the two-dimensional dam beak test case is also discussed.