抄録
In order to grasp visibility characteristics of helmsmen, visual observation distance error characteristics of the navigation officers and cadets were investigated. The investigation revealed the following items : Average error of the visual observation distance was 6% for navigation officer and 41% for cadets. Absolute value average error is 21% for navigation officer and 46% for cadets. Compared to relative distance in true value, the visual observed distance error tended to recognize remote places and tended to increase in proportion to the relative distance.
