On a three-decker like the Victory, every deck below, 2 gun decks and probably one or more decks below would be strung every night fore and aft with hammocks, which I think were allowed a regulation 16 or 18 inches width so that they could string hundreds of hammocks on each deck. In addition to these sleeping quarters, there would be separate spaces for midshipman, lieutenants, bosun, carpenter and others. And that answers how they could have 1,000 men aboard.
Yeah, it was tight, cramped, full of people.
And these days we have huge steel ships.
And at times it’s hard to find anyone else onboard.