There are many uncertainties in the interpretation of full-scale sailing vessel data taken under dynamic conditions, and even more uncertainties when forensic analysis is attempted based only on survivor’s recollections. Frequently, the analysis is based on static equilibrium assumptions, sometimes modified to steady-state motions of the wind and heeling response of the vessel. Dynamic conditions are generally non-deterministic and statistical methods must be used. Even more complicated is the non-stationary random process nature of most accidents. In the wind-heel research carried out on Pride II, it has been shown that wave action frequently adds uncertainty to the correct attribution of contributions to establishing the cause of the resulting heeling action. The best data are found in steady 10 to 20 knot wind strengths in minimum waves found in the lee of a shoreline. This criteria can be interpreted as minimizing the uncertainties in characterizing the wind-heel performance of a given sail combination at normal angles of heel...

Static pressure tests on sections of yacht hulls, manufactured to copy the structure of certain yachts which failed in service due to slamming loads, are reported. The materials of construction were aluminum, steel, plywood and fiberglass. The failure modes and pressures are discussed. In addition, some tests in which mild steel plates, corresponding in construction to the mild steel hull tested under static pressure, were loaded impulsively by the shock wave from an explosive charge detonated in air. The design of hull plating should take into account the impulsive nature of the loading, and the actual mode of failure. Neither the design impulse, however, nor the means for predicting the hull plating response to it are available from the current literature. If resort is to be made to the design of plating for simple static pressure, then a design pressure of at least 350 kPa (51 psi) is suggested for the bottom plating of yachts of about 13 m (43 ft) length overall. This is about five times the pressure required by the ABS Guide.