Bubblyrat the "tot" that both you and I enjoyed in the Royal Navy bore no resemblance at all to what it was back in the 1740s when introduced to the Fleet by Vice Admiral Edward Vernon:

"Grog - a drink made with water or "small beer", lemon or lime juice and rum."

The purpose was two-fold:
1: The citrus juice and the rum helped make the barreled small beer or water that was likely to go off "drinkable".
2: The diluted spirit reduced drunkenness and accidents aboard.

"rum mixed 2 and 1 with water" - you must have sailed in "Big Ships" - small ships routine was 1:1 - On the Minehunters and in the Shore establishments that had a diving team attached the divers got their's late and neat on the days they were in the water.