Hotbunking is when there are more sailors on a ship than there are racks (beds). In this case, sailors have an assigned period they are allowed in the rack and under worse case conditions, three sailors are sharing the same rack each day for 8 hours each. This practice is called hot bunking because the bed is still warm from the previous guy, when you go to lay down in it. This arrangement is far more common on submarines, where space is at a premium and often reserved for weapons/engineering as the priority.
On one sub I was on (the Narwhal), one of my hotbunk mates sweat profusely, so much so that there was a yellow outline of his body on the sheets (reminding me of one of those crime scene diagrams when a dead body has its layout being marked on the street). Even though I was quite the hardy soul and sailor, I rejected such sleeping conditions and instead learned to wad up some blankets and sleep between two torpedoes that were racked together.
Sheets and laundry are only washed once a week, by the way. And everybody bathes on the same day, so that everyone has the same amount of body odor. It seems much more tolerable that way. In the meantime, we all wore 'poopie suits' which are lightweight jumpsuits with no underwear/undershirt (can't afford the laundry activities on a sub...).
The other activity I told him about was a 'cruise sock.' This was a dirty sock that you shove down the side of your rack, between the frame and the mattress. Most guys jerked off in bed and just packed their pecker into this sock and whacked off. By the end of a cruise (usually 45 to 90 days), this sock was stiff as cardboard. Sometimes there was one sock and multiple guys used it. Other times there were individual socks, stored at different places along the mattress in a personal system worked out by the guys assigned to that rack.
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