Injury criteria of the IMO and the Hybrid III dummy as indicators of injury potential in free-fall lifeboats

During certification of free-fall lifeboats, it is necessary to infer the injury potential of the acceleration forces exerted on the occupants during water entry. Such an evaluation is required by the International Maritime Organization (IMO) and most regulatory authorities. The dynamic response model and the square-root sum of the squares method are two criteria included in the IMO recommendation for testing lifeboats. At least one national authority requests use of the Hybrid III human surrogate when inferring injury potential. The purpose of this paper is to compare the potential for injury as indicated with the IMO criteria and that obtained through use of the Hybrid III manikin. The comparison is based on data obtained during prototype tests with full-scale free-fall lifeboats launched from heights of up to 30 m.