Several navigation systems of large high speed vessel were evaluated by the evaluation method introduced in the former paper titled “An Evaluation Method of Navigation System of Large High Speed Vessel in Congested Water Area”. The main components of these navigation systems are radar, ARPA, information aid of a navigation assistant. In this paper, first the limit density of running ships was obtained by simulator experiments. The value is 6 ships/nm². Next by the simulator experiments on the scenarios with traffic condition of 6 ships/nm² and several navigation systems to be examined the effectiveness of the navigation systems was evaluated. By the evaluation the effectiveness of ARPA and information aid for collision avoidance decision from a navigation assistant can be pointed out. And when the index is only the limit distance to start collision avoidance, the examined large high speed craft may be able to run in the area density of which is smaller than 6 ships/nm² at 50 knots, and the most effective navigation system would be composed of RADAR the period of which is 3 second, ARPA, information aid for collision avoidance decision from a navigation assistant.