Mental workload is useful for evaluating the performance of a ship's navigator and a bridge teammate: a captain, a duty officer, a helmsman, or a pilot. The heart rate variability, the nasal temperature, and the salivary amylase activity predict performance well based on pre-experiments. However, most of the research was carried out for a professional's skill. A student's skill has not been evaluated yet. In this work, we evaluate a student's heart rate variability (R–R interval) as he guides a ship from a narrow channel to an open sea for a simulator training, and consider simulator training effects. The experiment was carried out using a ship bridge simulator, not a real ship. We show that the R–R interval is a good index for the evaluation of the simulator training. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.