The potential benefit of predictive information for navigation support was investigated in a simulator study. Twelve participants had to guide a medium-size vessel across a traffic separation scheme. In the simulator, critical vessel traffic scenarios were created, where participants were provided with: (i) baseline Automatic Radar Plotting Aid (ARPA) information, and (ii) baseline ARPA information supplemented with capability prediction information. This is information that shows the predicted manoeuvring margins of the vessel, indicating the predicted boundaries of safe operation. Results of the experiment indicate that capability prediction allows better anticipation by the navigator, significantly improving ship navigation performance.