Efficient and sustainable naval design: Exploring the impact of vessel lengthening on propulsion and stability

Enhancing sustainability in ship design requires innovative solutions that improve environmental impact and operational efficiency. This study evaluates the impacts on propulsion and stability of lengthening five meters at midsection an offshore field support vessel FSV. The primary goal of this modification is to increase deck cargo capacity and reduce the Energy Efficiency Design Index EEDI. However, this hull modification introduces technical challenges related to the vessel's stability and operational performance, particularly in maneuvers requiring precise positioning. The comparison between the original vessel and its lengthened version using the same propulsion system assessed parameters such as intact stability, brake power, performance under dynamic positioning systems, and potential resonance during dynamic anchoring conditions. Results highlight an increase of 138 tons in deck cargo capacity, working with the same draft of 4.25 meters and a significant 19,67% improvement in the EEDI, positioning the lengthened vessel as a sustainable and competitive alternative. On the other hand, a 2.23% increase in brake power BkW required at 14 knots was observed, along with a slight 0.36% reduction in propeller efficiency due to alterations in hydrodynamic flow.