1987 Volume 77 Pages 125-132
A Ship survey was made on evasive actions and mental load on board the Seiunmaru aiming to decrease the load at evasive action in congested waterways. Here, analysis is made on the relation of the Collision Judgement Index and human reactions, the former having been proposed by Kobayashi and Endo. It gives results as following: (1) The upper limit of the Collision Judgement Index at starting time of evasive action is approximately equal to 100 (×10^<-4>) and most of DCPA is less than 500m (=5L, L*ship length). Almost all evasive action are finished before TCPA reaches 2 minutes which roughly corresponds to 7L. (2) The frequency of heart pulse increases by 26±5% from the ordinary value which indicates increase of mental load. Above consideration leads a proposal to display an equialtitude map which enables quick look of the Collision Judgement Index.