Conceptual design recommendations to improve seakeeping of small high-speed craft providing interisland transportation in Galápagos

Abstract

To reduce the negative effects on passengers of the high-speed craft motions in Galapagos inter islands service, an optimization procedure at conceptual design level is developed. First, time histories of vertical acceleration of midship and forward end are first measured and analyzed. Weighted acceleration signals are compared with those from well-known experimental tests and are also used to evaluate the index of motion sickness with ISO 2631 standard to determine the number of persons affected by craft motion. The report from the sea trials includes the number of persons vomiting and those experienced dizziness because of the motions during the two-hour inter islands trip. Then, an optimization procedure using feasible directions is implemented with a combination of resistance and CG acceleration of the vessel to be minimized. Both functions were evaluated using well-known empirical formulations. The results show that increasing length and deadrise angle, and moving LCG forward, it is possible to reduce the acceleration by 20% while obtaining a 4% reduction in resistance.