I’ve written answers to similar questions before — here’s a pertinent link. Just going to drop it in here because formatting on the app can be weird:
The short version of that is that sailors would indeed drink alcohol during the working day — it was a perquisite that they guarded jealously — but they also had ready access to a barrel of water and could drink from it freely throughout the day. (The barrel was a butt that had been scuttled, that is, it had been opened, hence the term “scuttlebutt” for office watercooler talk today.) The daily rum ration was a quarter pint served twice a day, mixed with 3 parts water, which means the official ration would only be two quarts of liquid a day, which is obviously not nearly enough for a full day of hard labor.
There's always room for discussion but perhaps the section Hygiene And Healthy Lifestyles from our FAQ will answer your inquiry.