Even though the hunter-gatherers slept less, their daily rhythms were not identical to those of people living in modern societies. While the three groups often went to sleep after sunset, they woke long before first light. They also stuck to a regular sleep pattern, waking-up at the same time from day-to-day.
It turns out temperature is also important. People from all three groups fell asleep as the night grew colder and woke up when it was coldest out. Temperature may be one of the oldest evolutionary signals that help regulate our sleep patterns… But modern lifestyles, complete with shelters and heating systems, have at least in part eliminated these temperature rhythms…
Older folks were typically morning larks, and the younger adult members of the group tended to be night owls. The authors speculated that chronotype variations may be an evolutionary adaptation to maintain a state of vigilance in communities of humans.
The hunter-gatherers are also much healthier. Not a single one is obese, and the mean BMIs among the tribes were between 18.3 and 26.2, which is considered quite slim. They also tend to have lower blood pressure, better heart conditions and higher levels of physical fitness.
Thus comes a critical question. If we can’t blame the lack of sleep as causing our obesity, mood disorders and the like, could it it be that the reason we feel so unrested is because of poor health?
The US military used to give Halcion to help with sleep. That likely still goes on though possibly with a different drug… Get called out on short notice, get on the plane for a 12-14 hour trip and before landing pop a different one to get you ready to go. They know sleep is important.
If a watchstander gets all their sleep in one block at night then a call-out in that period is going to result in more fatigue.
On the other hand when the sleep schedule is in two segments than if the so-called anchor sleep is interrupted than the nap can be longer to compensate.
For example when I sailed third mate (0800-1200 and 2000-2400 watch) I generally slept from about midnight till 0600 hrs with a nap sometime after noon before 2000 hrs. If I got called out at night I would sleep longer in the afternoon if possible.
I should add that I sailed as mate on tugs with the two-watch system before I sailed third mate.
Matthew Walker, had a good podcast on Joe Rogan. Hes a neuroscientist and one of the world highest regarded sleep experts. Defintelty worth a listen. Im sure there are other avenues if you dont care for the Joe Rogan part.
I changed some habits after listening to Matthew Walker…one of the best podcasts that Ive listened to and actually took something away from.
Hes currently working with the WHO to get sleep highlighted in health education. They just completed a study where young students didnt start class until 0900am to guarentee a natural sleep cycle. Their grades were over 40% of the national average.
Edited to add that I worked 6/6 on tugs in the early 90’s. You can have that. But, Matt Walker does highlight benefits of biphasic sleep cycles, but not at the cost of 7 hours uninterupted sleep which is the recommended minimum for adults to go through the entire brain chemistry cleansing process.
Well of course WHO would find student performed better if they didn’t start class until 9AM, I doubt that was due to natural sleep cycle, they likely just became more coherent at 9AM. The natural sleep cycle of an undergraduate is a a misnomer. There is nothing natural about the sleep cycle of a 18-21 year old person.
I believe the point was that school start and stop times were driven about the work day of parents in modern society, to get the kids to school before the parents went to work versus no natural sleep cycle consideration. The group was younger, i think around the 13-17, still developing, not the typial college aged young adult. You pick your schedule at that point.
Anyway, that was the data across several seperated groups.
Having to work the 6 and 6 most of my 47 years at sea especially on 5 man tugs on the west coast and alaska there is never enough sleep between meals, washing clothes, bunkering the vessel and voyage maintenance along with making and breaking tow, I have work3d a 4 and 8 on a ATB and liked it the trip gave me time on my own for maintenance while my assistant stood his watch, getting 4 hours sleep of real sleep was a luxury on the 6 and 6.
On the Aleutian freighter it was about 8 days from Seattle to Dutch all on 6/6 watches. That part seemed OK to me.
In Dutch we’d work long hours, sometimes 24+ hours. Crew was very tired upon departure but after about 2 or 3 days at sea it was OK again. Gulf crossing was boring of course but the Inside Passage was interesting enough that the watches would go by relatively quickly.
I think the 2 watchstander system would be OK if it followed STCW work/rules.
Section A-VIII/l of the STCW Code states that watchkeeping personnel (i.e., all persons assigned duty as officers in charge of a watch, or as rating forming part of a watch) shall be provided a minimum of 10 hours of rest in any 24-hour period. The period of rest may be divided into two periods, one of which must be at least 6 hours. Also, the watch schedule is to be posted where it is easily accessible.
" Furthermore, the 10 hours of rest may be reduced to a single period of 6 hours for up to two days, as long as the seafarer concerned is provided with at least 70 hours of rest each seven day period.
I don’t know how many tugs etc meet this standard, not many I don’t think.
How times change. Now on an Aleutian freighter cargo ops in Dutch are usually a breakfast to dinner thing. Even the transit time to Dutch has been shortened by a day or two.
Sounds like it has changed a lot. When I worked for your former competitor, we’d get to Dutch and work until we were finished, and then leave. Sounds civilized now. Haha
Yes, it is compared to some of the tugs schedules I’ve been hearing about.
Anyway, the terms 6/6 and 4/8 are deceiving. At CTl both 6/6 and 4/8 watch schedules are encountered, but in either case the crew switches over to daywork once they reach Dutch Harbor, and average less than 11 hours a day for several days in a row. So the schedules aren’t really 6/6 or 4/8.
And watchstanders are different than crew. At CTI the cook just cooks, an average 10 hours/day. No watches. No cargo ops.
My bet is there are plenty of hybrid-schedule operations like this at other companies, and they shouldn’t be lumped in with operations where everyone works 6/6, 12 hours/day (maybe more?..) for a month.
2 years ago the company installed a fancy gizmo at the bottom of the Bridge stairs that we were supposed to wave a magic card at to record our working hours.
They never bothered to install it and the Chief Engineer took the tablet out to use in his cabin.
I got fed up with looking at the blank perspex on the box so put this in instead:
Myself and the Master have a combined seagoing career of 92 years so it seemed quite apposite, especially as we spend most of our time ranting and raving.
And dribbling.
That’s more or less what I"m saying. If the standard is: " After an accident was fatigue a factor?" than the STCW work/rest rule might be relevant. It’s possible to meet that standard with two watchstanders.
In practice meeting the work/rest rules with two watchstnaders is in many cases not going to leave enough time for call-outs, work in port and so forth.
The goal is to measure the actual fatigue level of the crew.
I was responding to @freighterman1 comment that to measure fatigue, just looking at whether the watch system is two-watchstanders or three watchstanders is not sufficiently granular.
I agree with this and in my experience tracking the work/rest hours and comparing it to the STCW work/rest requirements, while not perfect using actual work/rest hours is an improvement over just using watch hours alone.
The fact that in many cases crews often exceed these requirements is an issue which is separate from the problem of monitoring crew fatigue using work/rest hours.
During the last few years of working I had to sign a work hours document prior to leaving the ship, which I did not fill out, someone who I rarely spoke with filled out everyone’s hours, but it indicated I worked 12 hours a day which was bullshit. I corrected the hours one time. That didn’t go over well but since such papers were never looked at unless something untoward happened, no problem.
Where does the 12-hr requirement come from? I though it was OPA-90 but the internet says this.
The United States of America Oil Pollution Act of 1990 (OPA 90) states that on a tanker operating in USA waters, a licensed individual or seaman may not be permitted to work more than 15 hours in any 24 hour period, or more than 36 hours in any 72-hour period, except in an emergency or a drill.
That’s similar to STCW which allows only 14 hours work in any 24 hour period and no less then 77 hrs rest in a 7 day period.
The only other regulation I am aware of is the CG requirement for 3 watchstanders on voyages over 600 miles.
