Impact of Pontoon Vessel Geometry on Allowable Passenger Weight Using USCG Pontoon Simplified Stability Test

A parametric analysis of stability was performed for more than 30,000 geometric variants of cylindrical-hulled pontoon vessels to quantify the impacts of vessel geometry and prepassenger displacement on the maximum passenger weight allowed by the US Coast Guard (USCG) Pontoon Simplified Stability Test (PSST). Variables examined included pontoon diameter, pontoon length, pontoon separation, deck height, passenger deck width, location of forward and aft edges of the passenger deck, prepassenger displacement prior to loading, and trim. Each pontoon vessel variant was evaluated using General Hydrostatics Software to apply the PSST to determine the maximum passenger weight allowed for that vessel. Graphical analysis of the data demonstrated that a vessel's allowable passenger weight increases with: an increased pontoon diameter or length of pontoon, a decreased deck height, a limited increase in pontoon separation or beam ratio, and a symmetrically decreased passenger deck width or length. Additionally, it was found that each specific vessel has an optimum prepassenger displacement, unique to its pontoon diameter and length of pontoons, which maximizes the allowable passenger weight. Finally, a method is provided to correlate the present results with prior related work by other authors that characterized pontoon vessel stability in the context of pontoon percent submergence.