This work serves as the initial base for a new vessel for Mermaid Boat Trips, undertaking day trips to the island of Klein Curaçao. The research aims to overcome two significant challenges: 1) Improving seakeeping, as the current vessel has too many passengers who suffer from seasickness, and 2) improving the sustainability of the company’s operations through battery propulsion. It is noted that ship design is a complex, multifaceted field with many contradictory and interdependent aspects. A few significant findings could be concluded: 1) A good frame of reference is needed in a project with this many unknowns. 2) A result can be achieved where less seasickness is achieved relative to the baseline, partly by applying slender catamaran hulls with axebows, and in part by reducing the ship speed from 17 to 13 knots (while in rough seas). 3) The ship structures and consequent mass play an essential role in the effectiveness of battery-powered vessels: the vessel needs to be as lightweight as possible to save on battery weight and cost. Further work is required to find true vessel motions (non-linear) and resistance in waves, to proceed to further iterations and detail engineering. It can be said with reasonable confidence that a solid foundation is laid in the design for a new vessel for Mermaid Boat Trips that mitigates the effects of seasickness and operates sustainably.