Only recently has beer been able to travel well. IPA , India Pale Ale, was the first beer that could survive the trip from England to India. I believe that the XXX mark designated a beer that could travel. That is where Double Diamond got their Logo. Beer is also very bulky and has a low alcohol content. Overproof rum was the drink of choice in the lower decks . It was cheap and did the job.The grog ration was very important, would be hoarded for special events. Sailors ashore is another matter, to this day sailors ashore are famous for getting in trouble.