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Choosing the Right Rotation

Several alternative schedules exist to ensure that crew and staff are well rested and better prepared to perform their duties. Numerous shipboard studies have shown the value of a circadian watchbill and schedule.

No one size fits all!

There are several common variations of watch schedules, each with its own merits and tradeoffs. Become familiar with some of the considerations below before choosing a schedule for your crew. Refer to the Crew Endurance Handbook and remember: the NPS Crew Endurance Team is also available for further consultation. 


Watchbill Selection


Common Circadian Schedules

  • 3/9 -- 4 Section Watchbill
  • 6/18 -- 4 Section Watchbill
  • 4/8 -- 3 Section Watchbill
  • 8/16 -- 3-Section Watchbill

Common Non-Circadian Schedules to be avoided

  • 6/12 -- 3 Section Watchbill, commonly used on USN Submarines, results in 18-hour day (6 hours of jetlag per day)
  • 5/15 -- 4 Section Watchbill results in 20-hour day (4 hours jetlag each day)
  • 5/10 -- 3 Section Watchbill results in 15-hour day (9 hours jetlag per day)

A circadian watchbill is any schedule which is built around a 24-hr day with stable sleep periods each day. Any circadian-based watchbill is generally preferable to rotating watches that are built on 15, 18 or 20 hour days. The 3/9 and 6/18 have been shown to be good 4-section rotations. The 8/16 and 4/8 are good 3-section options that result in better circadian alignment. Of course, the type of watch activity and the number of qualified watchstanders must always be taken into consderation when choosing a watchbill.

Download more circadian watchbills here.

Other 24-hr rotations:

  • 4/8, 6/18, 8/16 schedules can also be employed, depending on the type of watch and the number of qualified watchstanders

See also, these relevant links: Choosing the Right Rotation, and Planning and Implementation for more details.

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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.