Among the euphemisms and colorful expressions used to describe extreme intoxication or drunkenness, the phrase three sheets to the wind often stands out as a particularly curious one. Some people might ask why three sheets as opposed to one or two, as well as what sheets have to do with overindulgence in alcohol. The answer lies in nautical history.
The original expression was actually three sheets IN the wind, not TO the wind. In the sailing world, the word sheet actually refers to a rope, not the sail it controls, although some nautical sources suggest the word did once refer to the corners of a sail. Specifically, a sheet rope controls the horizontal movement of a sail, while other types of ropes keep the sails vertically or statically stable.
If one sheet becomes loose or is improperly secured, the sail may flap in the breeze but the ship will still be relatively steerable. The loss of two sheets will make the sail too loose to maintain a straight course, but the captain may be able to compensate by manipulating other sails. By the time three sheets are in the wind, the ship will flounder and wobble, much like a drunken sailor on shore leave. If four sheets are in the wind, the ship is virtually dead in the water.
This is why a person in a drunken stupor would be described accurately as being three sheets to the wind. He or she would be just as unstable and uncontrollable as a ship with three sheet ropes flapping uselessly in the breeze. The expression most likely started with sailors who described their own state of public intoxication according to the number of sheets they were missing.
Being one sheet in the wind meant being tipsy, but still able to perform essential job duties. Two sheets would have meant being clearly intoxicated, but still able to walk unassisted back to the ship. Being three sheets in the wind meant extreme drunkenness, accompanied by unsteadiness and an altered state of consciousness. The worst case scenario would be four sheets in the wind, which usually meant total unconsciousness and possible alcohol poisoning.
Considering that the nautical scale of public intoxication only reaches four sheets, becoming three sheets to the wind after a night of wine, women and song may not be the best plan in the world. Cutting back a sheet or two might be a safer bet for all concerned.