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FAQs for Circadian-Based Watchbills and Shiftworkers

A circadian-based watchbill is one that assumes a work and rest schedule based on a 24-hour day—one in which you go to bed and wake up around the same time each day. For shiftworkers (that is, someone working other than a 9 to 5 routine), two common challenges exist: how to get good sleep outside the typical nighttime sleeping hours; and how to adjust to the "jetlag" experienced when rotating to a different shift. 

These frequently asked questions have been designed to facilitate US Navy shipboard operations. However, the principles apply to other operational environments.

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Frequently Asked Questions about Circadian-based Watch Schedules

  • Obtain 7-8 hours of uninterrupted sleep per 24-hour period, preferably at the same time each day
  • Compensate for any sleep loss with naps of 30 mins or 2 hours in length
  • Exercise, but no later than 2-3 hours before your bedtime
  • Avoid large meals and beverages—especially caffeinated and alcoholic beverages—before bedtime
  • To the extent possible, use a 24-hour circadian rhythm to set the foundation for your daily work and rest periods
  • Build a stable daily work schedule that maximizes rest opportunities
  • Minimize shift rotations to allow your circadian clock to adjust to your work schedule
  • Use caffeine during the first part of your shift to promote alertness at night
  • Learn the effects of good sleep habits and put them into practice
  • Get supporting analysis before you make a final decision to change the work and rest schedules of your crew
  • A circadian-based watchbill is based on a 24-hour day in which watchstanders work and sleep at the same time on subsequent days. 
  • The sum of all duty and off-duty periods, including sleep, should equal 24 hours.
  • The timing of the major sleep period is considered closely; whenever possible, opportunities are given to sleep during nighttime hours.
  • Work periods are aligned with higher circadian alertness for the individual worker.
  • If sleep must be split into two segments, care must be paid to the sleeping conditions and the timing of the sleep periods to ensure that sleep opportunities can be utilized effectively.
  • Requires 4 qualified watch teams
  • Watches are 3 hours long, with 9 hrs off between watches
  • Teams stand the same two 3-hour watches each day.
  • To best leverage circadian-based schedules, spend at least 3 weeks on the same rotation
  • Consider rotating the watchbill to coincide with port visits
  • Ona 3/9 watchbill, rotate forward by adding an additional hour of watch to each of three watch sections on rotation day
  • Lengthening the day is easier on the body than shortening the day (think about the difference you feel in flying from the east coast to the west coast versus flying west coast to east coast.)
  • Circadian sleep makes for more wakeful and attentive watchstanders, especially on the night watches
  • Shorter (3 hour) watches allow better focus while on watch
  • Standing the same watch each day provides stability and increased proficiency.
  • A stable routine improves morale, allows more time for PT and Qualifications
  • Sleeping at the same time each day reduces long term fatigue and sleep debt
  • 9 hrs off  watch allows adequate time for sleep (7+ hours) as well as personal time
  • Shorter time in hot environment reduces heat stress for engineering watch standers -  PHEL curves are not invoked
  • Allows stable team building across several watch stations (bridge/CIC/engineering).
  • More turnovers per day require more diligence in turnover process
  • Requires modifications to daily routine to allow sleep periods for every watchteam 
  • Requires 4 qualified watch sections—this must be a deliberate goal
  • Challenging to incorporate extended or unplanned evolutions like Underway Replinishment or VBSS
  • Some divisional manning cannot support a 4 section watch (for example, technicians/first division).
  • Codify business rules in a ship's instruction: build the daily routine to support the watch teams vice asking the watch teams to adapt to the schedule. 


  • Hold quarters later in the day—before lunch
  • Establish mandatory sleep periods for each watch rotation
  • For divisions with less manning, consider splitting the division between "pure" watchstanders (for example, the 6 on/6 off  schedule synchs nicely with 3/9 rotation) and standard "work force" for - PMS and maintenance. These roles can rotate/swap every week to maintain proficiency
  • Eliminate reveille call to allow 12-03 watch standers to sleep in
  • Eliminate taps to allow 00-03 watch to sleep in
  • Move evening prayer to lunchtime
  • Avoid admin meetings before 0900 and after 1600
  • Adjust meal hours to serve breakfast at 0530 and dinner after 1800
  • Add a healthy "midnight snack" at 0000 for night watch teams
  • Hold the Ops/ Intel brief at 1530
  • Delay XO messing and berthing until later in the morning.

Do not:

  • Require all hands to be awake during certain periods of the day
  • Require the night watch teams to attend morning quarters
  • Hold meetings after breakfast or dinner that require attendance by watchstanding personnel who are scheduled to be asleep
  • Ignore "off-duty time" by calling off-watch personnel while they are sleeping
  • Refuse delegation of duties by CO/XO to principal assistants
  • Refuse delegation of duties by Department Heads to principal assistants
  • Try to apply the same watch template to all situation
  • Fail to seek frequent feedback from watchstanders and other crew members.
  • Any circadian rotation (a 24 hr day with stable sleep periods) is generally preferable to rotating watches. 3/9 and 6/18 are good 4-section rotations.  8/16 and 4/8 are 3-section circadian options.  One size will not fit all.
  • Leaders should hold frequent informational calls both before and after implementation to solicit feedback and address issues.

1. Start planning 6 months prior to deployment.

2. If you have the manning, establish a skeleton 4 section watchbill

3. Identify special teams (VBSS, etc. based on expected mission) that may be non-watchstanders

4. Identify divisions where 4 section watch is impossible - look at contingency plans

5. Empower the CPO and First Class Mess to devise a workable daily routine and submit to the XO and Senior Watch Officer

6. Establish priorities early in case something must fall off the schedule

7. Examine communications paths in case quarters is not planned every day

8. Assign PQS to support 4 section watch bill

9. Tailor ship's instruction to cover both watch bill and briefing/meeting policy

10. Consider berthing arrangements to accommodate watch standers on similar rotations

11. Establish a crew training plan to share with the crew - benefits, challenges and lessons learned.  Revisit occasionally to get feedback and check progress.

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Crew Endurance Team
Naval Postgraduate School


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Share Your Experiences

If you have been on a ship that implemented a circadian-based watchbill, consider sharing your experience with the fleet.  

Contact the Crew Endurance Team at NPS to pass along Lessons Learned and Success Stories.