3sheets to the wind

The old adage "3 sheets to the wind" comes from the sailing community.  The "sheets" in the phrase are not the sails, but the ropes. On board,they are never called "ropes ." They are named according to there function : halyards- move or hold things vertically, sheets-move ie hold things horizontally, and lines which hold things in a static position.  The sheets in this case are the ropes that hold the sails in place. If one sheet is loose, the sail will flap in the wind and the ships progress will slow. Two sheets loose( "in the wind,") and you have a real issue. With 3sheets in the wind,the boat acts like a "drunken sailor. "
     For the most part the total number of sheets is a rating system for inebriation among land-lubbers and sailors alike. One sheet meant tipsy,two sheets meant leaning to the left or right,four sheets was complete unconscious.  And of course three sheets,insert your own definition here.