High-speed planing boats are subject to repeated slamming impacts, which can cause structural damage and discomfort or injury to passengers. The structural and seakeeping aspects of the design of high-speed craft are mainly determined through empirical estimates of mean and peak pressures. The primary structural guideline (Allen and Jones, 1978) relies heavily on semi-empirical criteria that are not always accurate and have limited application. The Allen and Jones guidelines provide conservative estimates leading to sufficient structural design, but do not provide enough guidance to allow strategic reduction in structural weight. Structural design depends on the hull bottom pressures while information about the magnitudes of peak pressures, time durations, and locations along the hull is generally not available. Model tests conducted at the US Naval Academy have measured bottom pressures on a prismatic planing hull geometry during operation in waves (both regular and irregular). Pressures were measured at point locations and using a two-dimensional pressure pad to examine how pressures change in both time and space during a water impact. Rosen (2005) presents a method for reconstructing the momentary pressure distribution during a hull-water impact. This method allows the measurements of a propagating pressure segment in one position of the hull at one instant in time to be associated with other positions at other instants in time (as determined from several different point pressure measurements). Morabito (2014) presents an empirical method for calculating the pressure distribution on the bottom of prismatic planing hulls. The method can be extended to the impact problem by use of an “equivalent” planing velocity. This paper compares the planing pressures predicted by Morabito's empirical method with the recreated pressure distribution determined from Rosen's method.

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