Development of a Method for Computing Wave-Impact Equivalent Static Accelerations for Use in Planing Craft Hull Design

Figure 1 illustrates the exhilarating experience of riding high-speed planing craft in waves. Riders experience motions in six degrees of freedom including heave, surge, and sway plus the rotations about the three principle axes. The challenge for the developers of current craft hull design methods was to analyze these complicated motions to understand the fundamental cause and effect relationships between wave impact loads and craft response motions. They then had to synthesize lessons learned with simplifying assumptions to make tractable an otherwise seemingly unsolvable problem: what pressure values to use in design calculations to minimize the risk of structural damage. This paper summarizes recent developments that are generally applicable to planing craft that weigh up to approximately 46,000 pounds with overall lengths 55 feet or less. Typical average planing speeds for these craft can vary from 25 knots to 40 knots or more in head seas characterized by significant wave heights typically in the range of 2.0 feet to 5.5 feet.