The ancient Royal Naval tradition of alcohol at sea pre and post the 1740's period.

I am not going to go over the British naval way of issuing and therefore supporting inebriation of its sailors both in peace and war. It happened, often producing "Dutch courage" when battle ensigns flew, but also produced a reliance upon alcohol which was the downfall of many in an idle peacetime navy. It can be covered in a simple sentence - the need for water; water goes stale; beer and wine doesn't; barrels of beer and some casks of wine easy to carry, use and stow; drunkenness occurs; reduce or get rid of beer; was a gallon a day and now half a gallon; substituted by rum; reduced in quantity and strength from half a pint to a quarter and then an eighth, with a mixture in grog of 4:1, the 3:1 and finally 2:1. 

Before Admiral Vernon's* time [an IPSWICH MP as well as a very senior naval officer], a gallon of beer [eight pints] was the normal daily allowance for British sailors, but his initiative added to it, but later supplanted the beer issue. His name and garment was used to coin the word "grog", based wholly on the spirit rum, that was harvested in and sold from the West Indies or the Caribbean into Admiralty bondage on a contractual basis. Those in the know will know that grog is a mixture of neat rum mixed with twice the amount of water mixed in.

* History is indeed dealt a sad blow when Admiral Vernon is chiefly known for his association with introducing rum into the naval service, whereas in truth, he was a passionate patriot, a fighter and achiever, who was sacked by the King [George II] and struck off the Navy List, so isolating him for the service he served so well and loved so much. During one of his commands in 1741 [HMS Princess Caroline] during wars and skirmishes in the Caribbean, his captain of marines [a British Army commission and appointment] was a colonial, an American called Lawrence Washington the half-brother of George Washington. Lawrence was so impressed with Vernon as a commander, that on returning to the USA as a civilian, he purchased land and built a house which he called "Mount Vernon". Upon Lawrence's death, George took over the house/estate and lived there with his family as the first President of the USA. He knew the history of the house and why Lawrence had named it so, and saw no reason to alter things. Still to this day Mount Vernon is still the Museum to George Washington the defeater of the British under King George III. There was a handful of naval officers who served as MP's in between Service appointments, but only two, Vernon and Beresford were gutsy enough to speak out for the navy against others in the House, arguing that the government was not doing enough to maintain a strong and effective navy. This rankled the government as well as the Admiralty. Beresford actually defeated the First Lord of the Admiralty speaking in the house, a man called Winston Churchill.  

It was very much a naval thing, although in certain circumstances soldiers were allowed generous amounts of the liquid bliss. The RN story is well told on my page so we take that as read.

The mid 19th century saw a great deal of drunkenness at sea for all mariners notwithstanding nationality or purpose, and that led to ship losses, unnecessary drowning's, and great inefficiencies both in naval and mercantile vessels.

The United States Navy, Marines and Soldiers all had gratuitous issue of alcohol on a daily routine basis which was one gill of measure. It wasn't rum though, but whiskey [made in the USA some rough and some smooth] whereas whisky was made outside of the USA, in places like Scotland and Ireland

If it is your intention to understand alcohol in the Royal Navy vis-a-vis the United States Navy [although there are other comparisons with other navies], I would strongly advise that you bother to read all that follows.