Some of the sleep thing depends on where you are, & what vessel traffic is like. If traffic is light, & say you're out in the open ocean, out of the shipping
lanes, then "proper" watch keeping is less of a priority, & you can grab some chunks of "extended" sleep. Say, a few hours at a time... often in a bunk, but near enough to your radar alarms & such.
In more travelled locales, sleep periods are shorter, & often in the cockpit. Assuming that you're not in the N. Atlantic in Winter.
One simple trick for this, is to make a hot water
bottle or two to tuck into your foulies, just prior to going to sleep. So that the extra warmth helps you to get some shuteye. And when they get cold, so do you, causing you to wake.
Regardless, as has been said, it's something which requires a bit of training. Both sleeping in short stints, & adapting to sleeping on deck
in your foulies.
Much of both can be learned by becoming part of the crew on a racing
boat. Where you have to do these things in order to pull your own weight.
But by virtue of being on a crewed boat, you also get support in learning
these skills. As there are folks to wake you. In addition to morale & emotional support for learning
how to cope with these things. And a comraderie created by everyone dealing with the same hardships for "fun".
For example, on night watches, prior to me turning in, & leaving the next guy to handle things solo. I'll make him a big cup or thermos of tea, coffee, or hot chocolate. Such goes a long way to making his watch easier. Both in helping keep him warm & comforted via the beverage. And in knowing that other guys onboard really care about his welfare.
Such traits & habits tend to spread, & become mutual. Making for tight crews, & good morale.
Also, and this is key: Due to all of the sail changes & other evolutions which go on on a racer
, you learn to sleep with an open ear. AKA being awake enough when sounds change in order to discern if you're needed on deck
or not to assist with things. So that it becomes easy to either get up & help with things on deck, or quickly fall back to sleep, with little time or effort involved.
Deliveries are a good tool to use for this kind of training as well, especially short handed ones.
And for the hard core
, you can seek out professionals who specialize in training folks for these kinds of things. Including doing sleep studies, where you're wired up to all kinds of monitoring etc.
On Ellen McArthur's record
, solo circumnavigation
on Castorama/B&Q, she was wired up to bio-telemetry gear
for the whole trip. And they would suggest to her when it'd be smart for her to grab some down time, & when it was okay to stay awake in order to really push the boat.
Much of this information being based on lots of lab, sleep testing done on her for a good bit of time, & lots of sailing (while wired up), prior to doing the record
It's also fairly easy to put together some tests or yourself to carry out at various times (24/7), & sleep intervals on land, as well as @ sea (with crewed backup for the latter). In order to see how well you perform at various sleep intervals & sleep lengths, as well as at what times during the day & night.
Then you can use said information in order to create watch plans for when you're sailing. And if you've the energy, also noting how well the reality of such matches up with the testing, & modifying things accordingly. Including what works best to help you to get back on sked, when things get interrupted by weather, or other events
beyond your control.
PS: The better physical & emotional condition you're in, the easier it is to both handle living & working on less sleep, & to bounce back from extended periods with none.
For example, if I'm in shape, then 2 - 2 1/2 days sans sleep isn't much of a trial, albeit, of course, the reverse is also true.