The need exists for a simplified structural review guide to enable U.S. Coast Guard marine inspectors to verify the structural adequacy of aluminum crewboats. The authors have developed such a guide. Typical existing crewboat forms and service speeds have been used to reduce the determination of impact pressures to a function of length and displacement. A design stress limit for the cyclic loading of the bottom structure has been determined based on wave observation data. Plating design has been verified by a comparison of sizing by beam theory versus elastoplastic analysis. A simplified grillage analysis has been used to determine the level of support provided by longitudinal plate girders or keelsons. A worked example and tables of section moduli for typical extrusions attached to plating are included as appendices.

This paper was originally prepared to provide discussion material for a proposed senior-level course in advanced stability considerations at the University of Michigan. The author has since revised and restructured the paper. The theory and history underlying existing intact stability criteria based on initial GM, righting moment balance and righting energy balance are discussed. Application of these assessment methods is shown and the critical weaknesses of each are addressed. Examples are drawn from current U.S. Coast Guard and IMCO requirements.