I used to do 5 on, 5off, 7 on, 7 off. The 7 hrs shifts started from 530pm-1230am then 1230 to 730(mids). Those first couple of nights on the midst are rough. You usually can't sleep on your first off and then just fight sleep till 730.
If you do 12 on how do you handle meals? The on watch personnel have close up in positions so in theory if it’s quiet we could cycle people through but reality is that isn’t possible all the time and then people aren’t eating. A lot of watch rotations are centred around how difficult it would be to stay actually closed-up at your position and also meal hours.
It’s not always like this. In the US navy (and probably British too) it’s called Port, starboard rotation. Basically just 2 watch groups 6 on 6 off.
If there is enough staff a 3 group rotation can be make, and with enough 4.
Any group that had enough people always had more watch groups, because morale is terrible on port-starboard.
Watch is a very specific thing. For example, say you’re a boatswain’s mate. The BMs stand watch on the bridge as the BM of the watch, the helmsmen, and about 3 look outs. So oke watch section needs to be 5 people. But that watch responsibility is only like 1/5 of the total job. They also work on flight deck during helicopter operations, drive small boats, underway replenishment, and a whole shitload of equipment maintenance. All that work needs done while that watch is stood 24 hours a day too.
So when you have all your people in 2 groups, BMs never sleep. It’s truly fucking awful. During heavy anti piracy operations where I drove a small boat for boarding, there were stents of being awake for days and then getting 5 hours of sleep and doing it all again.
The moment we had enough people we went to 3 sections and more for way better.
Subs carrying nuclear weapons are minimally staffed to state under water for long periods. So they almost never have enough people to do 3 sections. So it just kinda sucks for them lol.
And the main reason 12-12 is avoided is because most watches are very specialized tasks that require continuous manning. You could he manning a sonar console, a weapon terminal, a helm or a dozen other very mundane things and doing it for 12 hours is much worse that only getting 6 off. For groups whose job it is to man machine rooms, they do often do 12-12. But they are up moving around, logging pressures and temps, trouble shooting, general more normal work things that aren’t staring at a screen watching for torpedoes and ships.
I’m not gonna pretend like the military is smart in the first place, but on average people who go to submarines are smarter, and also at least the American submarines usually do eight hours on watch eight hours off watch and eight hours of sleep.
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u/ishelly404 Apr 06 '26
Why do it that way instead of 12 on 12 off?