Sleep Science and Watch Keeping Schedules

[packeteer]

I cant stand shifting schedule. that's why on my last delivery I asked for the midnight to 3am watch every night

[boatman61]

Originally Posted by BlueBuddha

Thanks Chris, I was wondering about this issue. This makes my original idea a bit tricky to pull off in rough weather because the long 5h shifts during the day. Although there are easy ways to split or share the day shifts into smaller chunks without entering a shifting schedule (Although I know some like you like the shifting schedule) :-).

What I would do is have watch and standby watch for the periods of bad weather.. basically keep the same routine but it gives everyone a 3hr and 5hr sleep and the same rest/activity period.. and there's always someone to hand who's alert and rested if you need spelling during your watch.. or a sail change.. lets face it.. the AP does the hard work.
Royal Navy influence.. half the watch works the ship while the other half deals with everyday tasks and sail changes and the just relieved Off Watch sleeps

Having said this however, I find I sleep on average 4-5hrs a day.. solo or crew..
I usually crash 11pm-2am.. with permission granted to leave me another hour if all is well and they are not fading.. then I may grab an hour in the day.. or not.
The rest of the time I'm on watch.. even when someone else is.. I can't help myself..
Great for losing weight..

[IRG]

After about 40,000 miles and employing many watch schedules, I've actually come back to the traditional dogged 4-hour watch with the rotating shift. Offshore I find sleep times to be arbitrary anyway and crew don't like to have the same watch over and over again, preferring to get the sunrise/sunset times occasionally. Offshore, no matter how you try, people's sleep is going to be interrupted by something including "all hands on deck" calls. 5 hours on or more can be very onerous, I find that fatigue sets in after 4 hours and a captain doesn't want that.

I've run the dogged 4-hour watch for extended periods with only 2 crew and we settled into it after a couple of days with minimum fatigue. I'm with others and as skipper I find that 4 hours is a pretty extended sleep. As for sleep science, that's all well and good in the lab or a nice calm bedroom but in a randomly moving boat? All variables are thrown out of the window I think enough to make it irrelevant.

Originally Posted by BlueBuddha

Hi all, I was having a conversation with a friend of mine who is a sleep scientist about watch schedules during offshore passages. I know this issue has been discussed extensively and I am familiar with most of the most common schedules. Yet, this conversation made me wonder how much the standard schedules have been informed by sleep science.

Take for example the common “3 hours on 6 hours off” schedule often used by 3 person crews. This schedule correctly allows someone to sleep for 6 hours, thus benefiting from all sleep stages and waking up during REM (and refresh). Yet this schedule forces the cycle to shift every day, so that your circadian clock never settles. This apparently is a big “no-no” in sleep science. My friend said “if you want to really mess up with their schedules, keep shifting their sleep every day. Your clock never sets and you’ll get disrupted sleep every day. It’s like sleeping in a new place every night”. The 3 on 6 off plan sounds like a good idea because no one is "stuck" with the bad shift every day, but this shifting of schedules can create havoc with people's sleep quality. Apparently the science of shifting schedules suggests that doing so keeps people from getting to deep sleep and do not feel rested even after sleeping for 6-8 hours.

Apparently, the key, from a sleep science perspective, is to provide 1) consistency 2) ability to sleep uninterrupted no less than 4.5 hours in 1.5 hours increment, with 6 hours being optimal.

I looked at multiple watch schedules and did not find anything that provides such set up for a 3 person crew.

So I played with different options and came up with this for a 3-person crew: Three 5-hour shifts during the day starting at 0600 and three 3-hour shifts during the night starting at 2100. This allows for all crew members to experience 6 consecutive hours of sleep sometime during night hours and yet keep the night shifts manageable at 3 hours each. This is also a stable schedule that remains the same day after day which helps the crew’s circadian clock to “set” and thus facilitate restful sleep. The plan would look like this:



As you can see, every crew gets to sleep during the night for 6 hours. Crew 1 from midnight to 6, crew 2 from 3am to 9, and crew 3 from 2100 to 3am. Every crew also gets a long period of off time of 8 to 10 hours.

For those of you who have done offshore passages with 3-person crews, any thoughts on this schedule? Any major problems you see?

Thanks! bb.

[captmikem]

It is very simple, don't make it so complicated.

The basic 3 person 4 on 8 off has been used on commercial ships for many years, and works. It is simple, you get used to it and it gives you plenty of sleep, you always know what time you are going on watch. No confusion.

If you listen to your ships clock, it gives you the watch, one bell each half hour until it finishes at 8 bells. It is very simple, it is tried and tested and it works.

I have used this system on yachts, ships, tugs, megayachts and have zero complaints.

Of note, on a circumnavigation with just two of us, 6 on 6 off works good, but when the weather is up or one gets tired, we change to 2-4-6-6-4-2. which works out well as you are only up in the middle of the night for 2 hours, and you are up for six during daylight.

Michael

[jackdale]

I like rotating shifts as well. I also like 2 people on watch.

With a two watch system I use 2 6 hour shifts during the day, then reducing the next 3 shifts by an hour each shift

0600-1200, 1200-1800, 1800-2300, 2300-0300, 0300-0600

With a 3 watch system - I like 4 hours on, 8 off during the day; 3 on, 6 off at night.

As many of my passages involve instruction, I try to keep myself off the watch system so that I can spend time with all crew / students. One of my former students was Lt. Commander in the Canadian Navy; he told me that naval captains are not on watches and show up on the bridge as needed. My standing orders include scenarios in which I am to be awaken.

Our circadian cycles evolved on the savanna. On the ocean different factors come into play.

[a64pilot]

I can't sleep four hours, but then again, I can't do a four hour watch in that after midnight, before dawn time either without a cat nap or two.
I don't have a good answer though, still evolving

[jackdale]

Originally Posted by a64pilot

I can't sleep four hours, but then again, I can't do a four hour watch in that after midnight, before dawn time either without a cat nap or two.
I don't have a good answer though, still evolving

With 2 on a watch, one of them can cat nap.

[gjordan]

Snowpetrol hit on what I think the most important variable in watch keeping is. THE TEMPERATURE!!!! I think rough weather is less hard on people than being cold. 4 or 5 hours of warm night watch is much easier than 2 hours of being cold. Warm clothes, jackets, foul weather gear, all help, but having done up-wind deliveries in January , the term cold to the bone becomes real. If your mate can only handle 2 hours, you dont get enough sleep. A couple of days of that and your brain doesnt function. I delivered a trawler yacht up the Calif coast in the winter, and found the warm pilot house almost enough to make me want to go over to the dark side and buy a stink-pot. The motion was terrible but the warmth made up for it. ___Just another opinion. ____Grant.

[bravenewworld]

Many very good comments here. You must be kidding with the schedule thing, really. I've been around the planet twice with two and three persons ad nauseum. I have always been a strong proponent for regularity regardless of whether you use UTC or local time. I always take midnight 'til 3 or 4 AM and someone else from 4 til 8 or so and then it is anyone who feels up to it. Pretty quickly, that "schedule" resolves itself with almost anything goes during the daylight hours. Why? just because everything else that needs getting done is at least as important as the watch cycle itself. That is hundreds of crew over the years that agree with the regularity and determining everything from the midnight watch component. I have been at sea for a month or more at a stretch in every ocean condition and weather type. Forget the whole "schedule" thing and have a raise of hands or simply appoint the watch schedule and let it go for a few days before making any changes at all. Not surprisingly, the body adjusts and the pain of it goes slowly, slowly away:-) The key is flexibility, flexibility, flexibility. Pretty quickly you find out who is more or less sleep tolerant, a very good thing to know on long ocean passages.

[a64pilot]

Originally Posted by jackdale

With 2 on a watch, one of them can cat nap.

Tried that, that was the professional capt's plan I hired.
Problem was, it was two hours on, two hours off with a four person rotation. Your dead beat on day one, we were hand steering, no autopilot, no Radar, no AIS, no map on the plotter.
I changed it on the second night to two hours on with one standing watch and four off as that was tolerable.

I liken it to standing guard in the military, same or similar concept.

[cenicero]

At least if you have a plan you can change it!!

[a64pilot]

Now that I remember it was three people, two hours sitting waiting to go on watch in the cockpit, then two hours watch, so you were in the cockpit for four hours, then had two off, then back in the cockpit for four more, then sun is up.
But we were hand steering so that means of course someone at the wheel at all times.

[hellosailor]

And then there is the USN. Who put the crews of nuclear submarines on 18-hour "days", literally. Three six-hour shifts (one for sleeping) make up one "day" on a nuke boat, and you can stash your conventional 24-hour watch someplace ashore because it won't have much use in your submerged life.


Along with sleep science you'll find things like a twenty-minute limit for acute concentration, i.e. helming a racing boat flat out in a storm. Or, more typical "high" concentration lasting no longer than two hours before performance degrades. And when you are "on duty" for a 12 hour shift instead of an 8-hour workday? At 12 hours, the accident and error rate actually doubles. Which fails to impress hospitals, who routinely put workers on a "12" hour shift, plus an hour of turnover at each end (so that's 14) plus overtime.


On a recreational sailboat, your best bet it to consider alternatives, ask the various crew what they need or prefer, and work it all out in whatever way keeps everyone most efficient and happy, if you can. No hard rules. A six hour "big sleep" is a very nice concept--unless your big sleep starts at six or eight AM on a windless bright summer day, and you've got to try ignoring some damned diesel in order to get it.(G)

[CarinaPDX]

I like the 4 on/8 off for three man crews. Personally for ocean crossing I have had 2 total, and use 6 on/6 off at night with a more flexible alternation during the day. After a few days it feels very comfortable, and keeps crew rested. On landfall mistakes are less likely and adaptation back to shore schedules is easy. Having seen the results of other schedules I insist on everyone getting a 6 hour rest every night, barring an emergency. Anyone who thinks they can make good decisions with 20 minute catnaps for 20 days is delusional - and the science proves it.

Greg

[secrabtree]

In my younger days I did deliveries between Hawaii and the mainland, usually San Francisco Bay, and Usually but not always from Hawaii. Crew size varies. The usual crew schedule was a very flexible "stay on watch as long as you feel right and call the next watch before you get fatigued". And I would have a printed watch schedule that I threatened to impose if anyone complained about someone taking advantage - either by shirking with short watches or by staying on watch longer than others thought that the long watch crew was really safely capable of standing watch. This usually worked well as everyone got enough long sleep and no one was on watch longer than safety allowed. With more than 3 I would not take a watch, but I did find that I woke about once an hour to check on things, including the person on watch.
On one delivery, a Farr 40 with no autopilot and tiller steering, I had the luxury of a six person crew and they wanted set watches. As I remember each person was on 4, but watches changed each 2 hours. So there was always 2 on watch, 1 was already fully awake and the other was waking up at the second hour. It seemed to work well.
An "aside". On that delivery one guy was a performer in musical productions. The lady that eventually became my wife followed him on the schedule, so she was on during the second half of his watch. She still remembers fondly that he sang show tunes to her while she was steering. I guess that I was lucky that he was and still is happily married.