Boats are an important mean of transport, for passengers and cargo, mainly in countries with high water wealth. Nowadays, electrification of transport includes water alternatives, but the efficient use of energy is still a key issue. Energy consumption in electrically–powered boats is highly influenced by several technical domains (e.g. Hydrodynamics, Battery, Propulsion, etc.). As literature reports advances in some of those domains, this paper focuses in the “Propulsion System (PS)” (Motor-Transmission-Propeller) design and optimization. When implementing an electric motor, the interaction of mechanical components may be analyzed to find the optimal variables that will define the boat performance and the optimal motor-transmission-propeller combination. This paper presents a methodology for multivariable optimization to maximize the overall efficiency of the PS, and therefore autonomy, in electric boats design. It proposes an approach from the physical variables that define the performance of the PS’s components, through an optimality problem formulation and an exhaustive search model that considers all possible values of the key design parameters. A case study is presented for an electrically powered river boat, where the proposed methodology enabled an improvement between 4-5% in the overall efficiency of the PS. This allows a better use of the limited available energy with a gain of 2.9 km (7%) in the most favorable case.

Eco design and sustainable design are words with increasing relevance in the development of new products. One of the main reasons is the growing worry about the environmental issues that the planet is having nowadays, hence the demand for products with this aspect included. Now designers have the opportunity to adapt useful tools to estimate the environmental impact of a design concept in order to develop environmentally friendly products. However, it is only in the last stages of design process where design teams have enough information to calculate the impact of a proposal. This calculation is a tedious, expensive and demanding activity and involving a high level of knowledge about materials, manufacturing processes and eco-design strategies. For this reason, environmental impact estimations gain relevance in the early stages of the design process, where more risks can be taken with a lower cost. This article suggests a taxonomy to analyze product’s shape; in order to offer a structured and systematic way of performing a morphology classification, being able to integrate this subjective aspect to other necessary variables needed to estimate the environmental impact. It offers a way to understand how shape, material and Manufacturing process are key aspects to make environmental impact estimations of preliminary concepts during the Conceptual Design.