The evaluation of mental workload using a pysiological index is useful to read the performance and the stress of ship bridge teammates: a captain, a duty officer, a helmsman, and a pilot. The heart rate variability (HRV) and facial temperature are fine indices for picking up during their ship handling. Moreover, in recently, the Micro Electro Mechanical Systems (MEMS) is popular worldwide, we can get a sensor by moderate price, and we are easy to compose some sensors freelyair temperature, humidity, air pressure, acceleration, and so on. We are able to evaluate the mental workload and the performance together without the stress of wearing the sensor, and it will lead to develop a healthcare monitoring system for navigators. We think we can prevent the human error by the monitoring system. In this study, we measure the HRV and body accerelations using a large model sensor, and show the results of pilot as a first step of the research.