Fatigue, Sleep and the 6 hr / 6 hr on/off watch schedule

I’m not defending the practice but I think some of the criticism misses an important point.

Biphasic sleep is distinct from monophasic sleep, which describes the way most people sleep. In monophasic sleep, a person attains all of their sleep in one block of time, typically at night.

Researchers hypothesize that monophasic sleep became the dominant sleep pattern during the industrial era, when artificial lighting began enabling people to stay up past sunset. Prior to that, many people across different continents and cultures followed a biphasic sleep schedule.

I have a fair amount of experience standing 6/6 watches. May be a better way to divide the watch with two watchstanders but as long as the total work day was only 12 hrs it was OK.

There is a problem of course having to work during rest periods or a noisy environment etc.

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We used to do 7/5, 5/7 which was much better.
On here they do 8/4, 4/8 which I wouldn’t like much.

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Dockings, drills, unannounced inspections in port, you name it.

There are too many added variables to make just about any watch system work in my opinion.


Don’t forget, you will always arrive and depart at meal times.
Unless it is the middle of the night of course.


My experience with the two-watchstander system was on a run with no drills, no inspections, more often then not no callout for mooring or unmooring. Basically there’s two officers capable of running the boat, the mate did not call the captain for any routine operations.

Again not trying to defend the 6hr/6hr system. Of course it’s possible to have very long work hours and not enough rest with the 6/6 system but I don’t think that the assumption can be made that watchstanders working 6/6 on a small vessel are going to necessarily suffer from more fatigue than those on a larger vessel with three watchstander and constant call-outs.

Unless of course, those on 6/6 are subject to constant call outs, as is common in the west coast/Alaska towing industry (harbor boats excepted).

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To make the logic more clear I edited my post to include “Of course it’s possible to have very long work hours and not enough rest with the 6/6 system”.

In some cases an effort to add a third watchstander to a boat working 6/6 is not likely to gain traction. Might be more productive, in some cases, taking steps to insure that off-watch crew do in fact get good rest.

Good post here:


I wonder what schedule tug boat and towing companies use in other countries. It’s always good to compare notes, perhaps someone can chime in.

I haven’t worked everywhere but I’ve never heard of a towing operation that worked 6/6 and ever called out crew for routine operations.

I edited my post to specify the geographic area I’ve seen it the most in.

To each their own, I guess? Never heard anyone who went to 7/5 asking to go back to 6/6 before, but, now I have.

In the good old days of course, 4 on/8 off which was much more civilized.
Just a distant memory now…

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Guess that will vary on how big the crew is, and if they are crewed up properly for their mission. For example, way back when I used to work on a tug towing dump scows. The AB on the back watch never had to get up off watch because the chief would help the front watch AB make/break tow. The AB on the front watch was the worst zombie on board, because he had to get up and help make/break on the back watch that only had one AB. He had the lionshare of the OT, but was exhausted.

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This is what I’m saying here. The AB on the back watch getting called out is a direct result of a short-handed crew. If there was additional AB or an assistant engineer on the back watch there would be far less problem with fatigue.

It’s high work-load and being short-handed that is a direct cause of high levels of fatigue here, not necessarily the 6hr/6hr watch schedule itself.

Years later, was sailing as an engineer on a harbor tug doing bunker work. When we were moving manned barges, no problems getting your six hours off usually. Then you’d get stuck with an unmanned barge for a few days, and the engineer was expected up off watch to help the ab/tankerman. Add to that a turd of a boat that needed constant maintenance/repair and whatever else popped up, I got no sleep. I suggested to the GM that they should add a 6th man. Make it an OS/entry level guy or an assistant engineer, whatever. I got laughed at and got told, and I quote ‘you don’t know what real tugboating is. You haven’t slept in a week? I haven’t had sleep in years.’


And here we have the crux of the problem in this industry. These attitudes that “real men” can withstand this kind of punishment and carry on unabated. Some sort of false pride in working in an unsafe manner but getting the job done anyway. It exists in trucking as well. Aviation seems to be the only one that has successfully transitioned to a more logical take on actual rest, but even then I am not so sure.

It boils down to my standard answer to anyone who asks me how we can fix the rest period problems. More people or more idle time where people can get actual rest. Both of which cost more money so we are all faced with dreaming it will be a reality.

Now I will await Herr Bugge chiming in with “not every company is motivated by money alone”. Well, I guess we are all waiting for that to be the rule, not the exception.


Or someone saying just tie-up / anchor the ship till everyone is rested up.

Way back in those “sleep when you are dead days” I have had a Captain, just barely miss a tide and have to anchor for 5 - 6 hours, and then take the anchor watch.

As others have pointed out, this is the meat of it. In the industry I mentioned, it’s 4-5 person crews on 6/6 with all hands for every berthing/unberthing and cargo ops, whether containers or anything else on the barge.

Until these outfits are required to man the vessels with enough people to work 6/6 with only rare callouts, exhausted tugboaters will be the norm. Changing that tough guy culture will take regulatory change (that subchapter M almost completely ignored), I don’t think anything else will do the job.

Sorry to take it off on a tangent, I think the point is that it’s not a particular watch schedule that is to blame for excessive fatigue, it’s undermanning while using less than optimal watch schedules that is to blame.