In maritime shipping, weather routing systems are popular to reduce fuel consumption and emissions. One of the most comprehensive overviews of applied optimization approaches to date has been compiled as part of this thesis. To ensure applicability for various types of ships and to reduce data requirements, weather-dependent ship motions and fuel consumption are frequently considered in a simplified way. Since simplifications are often regarded as insufficiently accurate, the objective of this thesis is to analyze the impact of ship performance methods on weather routing. Therefore, a graph based ship weather routing system is developed in C++. It aims at minimum fuel consumption by route and/or speed optimization. When optimizing a voyage, either a rather simple ship performance method, referred to as added resistance method, or a more advanced, so called added power method can be selected. The latter includes a maneuvering model as well as propeller and engine characteristics. Calculation runs for various routes, arrival times and weather conditions are performed and selected results are compared to data collected on board of container ships.