In our paper, we present a new model for PV boats named RhinoSimSol, which is supposed to support simulation of the design of PV boats to evaluate PV boat performance in an early design stage. The model comprises various algorithms such as for solar trajectory and irradiance calculations to determine indicators of the PV boat's performance in an early design stage. In order to determine these indicators for PV boats, scenarios can be used which let the user chose various options, such as a sailing route, start time of sailing and time of year. In order to demonstrate the functionality of RhinoSimSol, we executed 54 simulations with various combinations of 9 PV modules and 6 batteries. The performance parameters we compared were 1) maximum average speed for a 30km trajectory, 2) autonomy of the PV system with an average speed of 12km/h and 3) the PV system component cost. The results of these 54 simulations, speed, autonomy and cost for the PV system, were compared with an actual PV system on an existing PV boat. Performance of PV boats are optimistic compared with real monitored data: 76% overestimated. This suggest the following could be improved: more PV system components, such as MPPTs, and a more accurate irradiation model. Our simulation approach in Rhino shows that it can help determine and improve the performance of PV boats in an early stage of development.