Issuing the grog ration, c1900
The Grog ration was introduced into the Royal Navy by Vice Admiral Edward Vernon on 21 August 1740 in an attempt to limit drunkenness. A half pint of rum diluted with a quart of water, issued by the purser (or 'pusser') in two servings before noon and after the end of the working day became part of the official regulations of the Royal Navy in 1756. When the tradition ended on 31 July 1970, by which time the ration had fallen to just one-eighth of a pint, it is said that more tears were shed than fell on the bier of Nelson.
The 'Scots Magazine' of Jan 1790 gives: "ORlGlN or GROG - Written on board the Berwick a few days before Parker's engagement With the Dutch fleet on Aug 5 1781, By Dr TROTTER", suggesting that the name derives from 'grogram' a type of stiff canvas used for coats.
A mighty bowl on deck he drew,
And filled it to the brink;
Such drank the Burford's gallant crew,
And such the gods shall drink,
The sacred robe which Vernon wore
Was drenched within the same;
And hence his virtues guard our shore,
And Grog derives its name.
From the 'Scots Magazine', Jan 1790
Early usages include (OED): 1770 T. Norworth in 'Gentleman's Magazine'. "Groggy; this is a West-Indian Phrase; Rum and Water, without sugar, being called Grogg." 1773 Edward Ives 'A voyage from England to India' "A common sailor..having just been served with a quantity of grog (arrack mixed with water), had his spirits..much elated."
Admiral 'Old Grog' Vernon
by Thomas Gainsborough