Designing ships for open water and ice requires a suitable design method to account for the distinct challenges in open water and ice. Ships with multienvironment capabilities are of high complexity as a result of design-coupling, which is illustrated by design matrices. In this context, this article presents a method that includes a ship performance evaluation method based on the Ship Merit Factor (SMF). The method combines the SMF with a route specific ship-dependent productivity and allows to compare the technoeconomic performance of ships operating in open water and ice. Consequently, the method is applied to a case study comparing the performance of different ship designs operating along the route Rotterdam to Yokohama through the Suez Canal and the Northern Sea Route. The resulting design approach indicates the necessity to include and develop novel simulation-based methods for the reliable assessment of ice-capable ships is discussed.