Rules and regulations are written in blood. The 1963 sinking of the USS Thresher (SSN-593) led to major changes in the way the Navy conducts maintenance and builds ships.1 The Navy needed a similar adjustment after the 2017 USS John S. McCain (DDG-56) and Fitzgerald (DDG-62) collisions.2 The lives lost were not the only price to be paid; millions of dollars were required to repair both ships.3 Reports on the collisions list several similar contributing factors.4 One stands out: sleep management and rest. Sleep management instructions and guidelines have been implemented across the aviation, submarine, and surface communities, but the Navy needs an improved servicewide policy.
Submariners and Sleep Management
The Navy understands the merits of sleep management. Prior to the John S. McCain and Fitzgerald tragedies, the submarine force changed its sleep rotation to account for the body’s circadian rhythm and developed watchbills to allow for a better rested crew.5 Previously, submarines operated on an 18-hour day: 6 hours on watch, 6 hours doing maintenance or for personal time, and 6 hours of protected sleep. When I arrived on board the USS California (SSN-781) in September 2018, the boat was operating on a 24-hour day: 8 hours on watch, 8 hours of maintenance or personal time, and 8 hours of protected sleep. Sailors who had experienced the previous 18-hour cycle noted that the shift to the 24-hour cycle was a welcome change.
Unfortunately, it took two fatal collisions before the surface fleet directed changes to manage rest. Under ComNavSurfPac/ComNavSurfLant Instruction 3120.2 released in 2017, watchbills were written to allow for a 24-hour schedule. This allotted sailors 7 hours of sleep in a 24-hour day as either 7 hours of uninterrupted sleep or as 5 uninterrupted hours with a 2-hour nap in the workday.6 This instruction also emphasized that there is a noticeable drop in a sailor’s performance after being continuously awake for greater than 16 hours and discouraged keeping sailors operating for prolonged periods. This policy was revised in 2021 to adjust the numbers to 7.5 hours of sleep, either in whole or as 6 hours uninterrupted with a 90-minute nap.7
While the changes are welcome, more can be done. A 2003 study found that 14 continuous days with 6 hours or less of sleep per night resulted in a cognitive performance deficit on all tasks. The performance of participants getting either 4 or 6 hours of sleep was equivalent to those experiencing two nights of total sleep deprivation. In addition, subjects were unaware of their increasing cognitive deficiencies. The study concluded that wakefulness for more than about 15.84 hours predicts a decline in performance.8
While the current instruction discourages keeping sailors awake for longer than 16 hours, it gives an option for watchbills to be written with a protected sleep period of only 6 hours. As shown in the 2003 study, 6 hours of sleep per night is not enough to prevent cognitive impairment. The submarine community also pushes the boundary of having sailors operate up to 16 hours per workday if a service member completes an 8-hour watch and finishes his or her day with 8 hours of maintenance. Both communities need better margins for safety.
The data does not stop there. A 2020 study compared automobile driving performance in three categories of people: those fully rested, those deprived of sleep for 24 hours, and those under the influence of alcohol. The study showed that individuals who went without sleep for 24 hours had reaction times 0.63 seconds slower for breaking and lane changing than the average, with alcohol impairment reducing reaction times by only 0.12 seconds.9 The conclusion was undeniable: Individuals who were sleep deprived had a higher deterioration of overall driving performance than those who were intoxicated. Shockingly, the study also concluded that coffee does not counter the effects of sleep deprivation. It should cause concern to know that sailors with severe sleep deprivation are effectively operating drunk.
In the early morning of 2 October 2021, the USS Connecticut (SSN-22) struck an undersea mountain, resulting in injuries to 11 sailors and millions of dollars’ of damage.10 The investigation listed many factors contributing to the collision, including poor navigational judgment and a lapse in procedural compliance.11 The report did not mention how rest and sleep were being managed on board the Connecticut. While proper sleep management may not have prevented this accident, it would have been to the Navy’s benefit to determine whether the crew and its leaders were experiencing any cognitive impairments because of the ship’s sleep management. That day the ship was damaged. In the next incident, the whole crew may be lost.
There is good news: The Naval Postgraduate School (NPS) released version 2.0 of its Crew Endurance Handbook in 2021 to help Navy leaders design watchbills around circadian rhythms that maximize sleep and minimize time on watch.12 However, more can be done. Protected sleep periods should stretch greater than 6 hours. Vessels that do not have the manning to support the NPS recommended watchbills could use a submarine’s schedule: Approximately a third of the crew would be asleep at any given time, as opposed to having a day-to-day routine during which there is a period when all hands are expected to be awake.
The aviation community already has moved to allow for more sleep. As of May 2016, the general flight and operating instructions require sailors to receive 8 hours of sleep per day.13 This instruction even covers what should be done to treat fatigue in the event a crew must continuously operate past 18 hours: provide 15 hours of continuous off-duty rest. Of course, larger margins for time expected to be awake ought to be given. However, the aviation community has the most effective sleep-management policy—offering long sleep periods, providing actions to take when the crew is operating past useful wakefulness, and emphasizing maintaining the crews’ circadian rhythm.
Looking Forward
The Navy needs a universal policy directing all communities to implement effective sleep management. A new policy can refine watchbills by requiring sleep periods to be at least 7 continuous hours (regardless of whether service members take a nap in the day), with sailors only allowed to have less than 7 hours of sleep at a time for two consecutive days. When operational commitments require sailors to be awake for greater than 16 hours, actions should be taken afterward to ensure they have time to rest. Investigations from mishaps and incident reports should investigate whether if sailors got adequate sleep. While the proposed policy improvements may not always be feasible on all ships, it is imperative to improve sleep management guidance and models for the Navy to build a system that maximizes safety, efficiency, and warfighting readiness.
1. Sam LaGrone, “After Thresher: How the Navy Made Subs Safer,” USNI News, 4 April 2013.
2. Megan Eckstein, “How Far Has the U.S. Navy Come since the McCain, Fitzgerald Collisions?” DefenseNews, 22 August 2022.
3. Sam LaGrone, “Stricken Destroyer USS John S. McCain to Be Repaired in Japan,” USNI News, 4 October 2017; and Sam LaGrone, “Repair for USS Fitzgerald after Collision Will Cost More than Fix to USS Cole after Terror Attack,” USNI News, 27 July 2017.
4. National Transportation Safety Board, Collision between U.S. Navy Destroyer John S. McCain and Tanker Alnic MC, Singapore Strait, 5 Miles Northeast of Horsburgh Lighthouse, August 21, 2017, Marine Accident Report NTSB/MAR-19/01, June 2019; and National Transportation Safety Board, Collision between U.S. Navy Destroyer Fitzgerald and Philippine-Flag Container Ship ACX Crystal, Sagami Nada Bay off Izu Peninsula, Honshu Island, Japan, June 17, 2017, Marine Accident Report NTSB/MAR-20/02, March 2020.
5. David B. Larter, “This ‘Life-Changing’ Shift Has Made Submariners Much Happier,” Navy Times, 28 October 2019.
6. U.S. Navy, ComNavSurfPac Instruction 3120.2, Comprehensive Fatigue and Endurance Management Policy, 30 November 2017; and U.S. Navy, ComNavSurfLant Instruction 3120.2, Comprehensive Fatigue and Endurance Management Policy, 1 October 2017.
7. Gidget Fuentes, “Latest Surface Navy Sleep Policy Aims for Better-Rested, More Alert, Healthier Crews,” USNI News, 28 January 2021.
8. Hans P. A. Van Dongen et al., “The Cumulative Cost of Additional Wakefulness: Dose-Response Effects on Neurobehavioral Functions and Sleep Physiology from Chronic Sleep Restriction and Total Sleep Deprivation,” Sleep 26, no. 2 (March 2003): 117–26.
9. Joanna Lowrie and Helen Brownlow, “The Impact of Sleep Deprivation and Alcohol on Driving: A Comparative Study,” BMC Public Health (June 2020).
10. Craig Hooper, “Congress Authorizes Millions for Repairs of USS Connecticut,” Forbes, 20 December 2021.
11. RADM Christopher J. Cavanaugh, USN, Command Investigation of the Apparent Striking of a Submerged Object by USS Connecticut (SSN-22) While Underway in the U.S. Seventh Fleet Area of Operations on 2 October 2021, U.S. Navy Pacific Fleet, 29 October 2021.
12. Naval Postgraduate School, NPS Crew Endurance Handbook: A Guide to Applying Circadian-Based Watchbills (Monterey, CA: 2021).
13. Office of the Chief Naval Operations, NATOPS General Flight and Operating Instruction Manual, CNAF M-3710.1, Department of the Navy, 2 May 2016.