Converting motorised sailing yachts to carbon-neutral vessels

Abstract

Electric motors powered with batteries that are charged by solar panels provide an attractive alternative to internal combustion engines as an auxiliary propulsion method for cruising sailing yachts, especially when shore electric power is not available. This project explores the conversion of existing yachts to the solarelectric alternative, making them quiet, clean and carbon neutral during operations. More specifically, we address the question under what circumstances currently available solar panels, controllers, batteries and motors present a viable option for converting conventionally powered cruising yachts to solar-electric auxiliary propulsion. We argue that small sailing yachts provide a more promising target for conversion than larger ones and that tropical conditions favour solar-electric propulsion. Thus, a small cruising sailing yacht operating in the tropics serves as a case study for conversion. The dimensions of the chosen boat, along with requirements on the desired range and charge time inform the choice of motor, battery and solar panels. We describe the design of a custom-made truss for solar panels, considering the required solar panel size, as well as ergonomic, aesthetic and mechanical design constraints. A finite element analysis of the truss simulates the wind load in severe weather conditions. We conclude with a preliminary evaluation based on test voyages in Singapore and Indonesia.