Effects of 60 hours of total sleep deprivation on two methods of high-speed ship navigation.

This study investigated how workload and performance in high-speed ship navigation was affected by sleep deprivation using methods based on either paper charts or electronic chart display and information systems (ECDIS). In two separate weeks, five navigators sailed 10 routes in high-fidelity simulators while undergoing progressive sleep deprivation for up to 60 h. Results showed that navigation performance was better using ECDIS, but was largely unaffected by sleep deprivation in both. There was significant interaction between speed, sleep deprivation and navigation method, indicating that navigators using ECDIS reduced their speed more while sleepy. Secondary task performance was reduced by sleep deprivation, but was equally affected in both conditions. Workload was higher in the ECDIS condition, as indicated by subjective ratings and heart rate variability. No significant differences in sleepiness were found, but electroencephalographic recordings indicated more frequent microsleep episodes in the ECDIS condition. This may be influenced by lower overall arousal while navigating with ECDIS.