Merchant Crew-Rest Provisions Should Not Be Applied to Navy Ships

Recently, the National Transportation Safety Board (NTSB) released the findings from its investigation of the 2017 collision of the USS John S. McCain (DDG-56) and the tanker Alnic MC. One of the report’s recommendations was that the Navy adopt the crew-rest requirements of the Standards of Training, Certification, and Watchkeeping (STCW) for all ships.¹ The STCW holds that sailors standing navigation and engineering watches must receive a minimum of 10 hours of rest in any 24-hour period, and 77 hours of rest in any 7-day period. In addition, required rest may be divided into no more than two periods in any 24-hour period, one of which must be at least 6 hours long, and the interval between consecutive rest periods must not exceed 14 hours. Since 2017, the surface navy has made improvements to crew-rest policies, but it has not adopted the NTSB-recommended STCW standard. Below, we describe the root causes undermining sailor well-being on surface vessels, assess the strengths and weaknesses of the STCW provisions, and contrast STCW provisions with current Navy efforts to improve crew endurance and operational effectiveness.

Root Causes that Undermine Sailor Well-Being

In 2001, the Naval Postgraduate School (NPS) Crew Endurance Team embarked on a multiyear effort to improve operational effectiveness in the naval environment through the optimization of crew performance. Based on data collected from more than 35 ships and approximately 1,700 sailors, NPS identified the first major root cause of poor sailor well-being: excessively long workweeks and rotating, non-circadian-based watchbills.² Based on these findings and combined with earlier research, the Crew Endurance Team recommended switching to circadian-based watchbills—fixed watchstanding schedules that result in a 24-hour work/rest day in which a sailor works and sleeps at the same time each day.³ Circadian-based watchbills are associated with less pronounced split sleep, higher alertness, less daytime sleepiness, less severe insomnia, better sleep quality, better mood, and better psychomotor vigilance performance.⁴ Sailors working on circadian-based watchbills, however, were not sleeping more than their peers on legacy non-circadian-based watchbills; they were sleeping better. This finding refuted the common argument levied against circadian-based watchbills—that sailors on those watchbills would have fewer hours to work.

In observing sailors’ work schedules, NPS identified a second major root cause of sailor fatigue: excessive workload and tasking requirements. Sailors worked about 12 hours per day, with approximately 25 percent of them working more than 13 hours per day and approximately 10 percent working more than 14 hours per day.⁵ Fifty percent of sailors worked more than 84 hours per week, and 10 percent worked a staggering 98 hours or more per week. One reason for these long work hours is that some of the tasks performed when ships are under way are not fully accounted for by Navy manning models.⁶ Yet another reason is that various higher authorities each impose requirements on ships, and no centralized oversight authority assesses how the requirements cumulatively affect sailor workload.⁷

STCW Provisions Contrasted with the Circadian-Based Watchbill Effort

The STCW crew-rest provisions are simple rules with specific minimum-rest criteria. The STCW provisions do not address the root causes of fatigue at sea but focus instead on guidelines that are easily assessed for compliance. By contrast, the circadian-based watchbill approach—integrated in the Navy’s Comprehensive Fatigue and Endurance Management Policy (CFEMP)—directly addresses the root causes of fatigue at sea, considers the specifics of the ship’s daily schedule, and provides guidance on factors known to affect sailor well-being. This approach is more holistic and tailored for the
Navy’s operational environment.

Furthermore, the typical civilian seafarer is not subjected to the chronically high workload and stress seen in the military naval environment. NPS research found that Navy sailors are besieged with persistently high workloads, driven by both scheduled tasks and unplanned events. Even though Navy sailors and seafarers sail the same oceans, the daily schedules of Navy and civilian vessels differ significantly. Hence, using research findings from, and regulations optimized for, civilian vessels should be done with caution.⁸

Notably, the NPS Crew Endurance Team recently concluded an assessment of the underway workload of Navy sailors as compared to various seafarer regulations, specifically, the Maritime Labor Convention, the U.S. Code, and the STCW.⁹ Results showed that Navy sailors worked more than the provisions in these seafarer regulations on approximately 25 percent of their workdays, 50 percent of any three-day work period, and 80 percent of any seven-day work period.

The NPS team’s findings suggest it would be impractical for the Navy to adopt the STCW crew-rest provisions at the ship level. Dictating rest criteria without addressing the root causes of fatigue will not improve crew rest at sea. More important, optimizing work/rest patterns by using appropriate watchstanding schedules seems more likely to generate spare capacity (in terms of improved alertness, better mood, and better psychomotor vigilance performance), which would be available in case of critical operational procedures and emergencies. The NPS Crew Endurance Team recommends against adopting the STCW crew-rest provisions for Navy ships. A better approach is to intensify current efforts to improve the underway daily schedule of ships based on the 2017 crew-endurance policy change and further optimize underway workload by reassessing the requirements imposed on ships.¹⁰