Assessment of a Novel Watchstanding Schedule on an Operational us Navy Vessel

Abstract

One watchstanding schedule used in the US Navy is the modified 6-hr on/18-hr off, a 6-hr watch followed by an 18-hr non-watch period. In this four-section watchbill, rather than standing the same 6-hour period each day, two 3-hr watches are “dogged”, resulting in a day shorter than 24-hrs in length. We assessed the 6-hr on/18-hr off schedule to determine its affordance of rest/sleep and psychomotor vigilance, comparing it to a 3-hr on/9-hr off schedule. Results show the 3-hr on/9-hr off schedule is superior, affording 0.63 more hours of rest daily (p=0.054), 0.89 more hours of sleep daily (p=0.024), and decreased variability in psychomotor vigilance (i.e., reaction time and lapses) compared to the standard schedule (p<0.05). Variability of daily rest and sleep is also reduced (p<0.05). Subjective assessments between the 3-hr on/9-hr off and seven other watch schedules showed that participants preferred the 3-hr on/9-hr off schedule. The 3-hr on/9-hr off schedule yields better sleep hygiene, more stable performance and is well-accepted by crewmembers.