"The Whole 9 Yards"

[svc40bt]

The explanation I have heard is that it is a sailing reference: a ship having three masts, each mast having three yards from which a square sail is hung thus, the whole nine yards is a ship under full sail.

[ForresterModern]

As Steve mentions there are a lot of stories but little science or documentation to support them. Below is a nice thorough if indeterminate discussion of the OP's question:

http://www.phrases.org.uk/meanings/t...ine-yards.html

[unixken]

The explanation I have heard is that it is a sailing reference: a ship having three masts, each mast having three yards from which a square sail is hung thus, the whole nine yards is a ship under full sail.

I would think that far too many variations in sail configuration exist for this to be the origin of the phrase (as interesting as it might sound.) For example, the Coast Guard's "Eagle" is a Barque design. It incorporates three masts, but only two have square sails. Each of the fore and main masts has 5 square sails (not three), and being under "full sail" includes far more cloth than just those 10 sails (the jibs, and everything on the mizzen mast, for example.)



And that's just one example of different sail configurations (a Cutty Sark would have 15 squared sails hanging from 3 masts, for example.) So again, I would have to doubt a maritime origin for the expression "the whole nine yards."

[The Wizard of BC]

As Unixken has pointed out the 9 yard phrase does not refer to a ship. If you use the definition of 'ship'. as codified but the time of the Napoleonic Wars, a 'ship' has three masts each with square sails rigged. (This is why The Eagle is a Barque)

For example: on just one representative ship from this period, a 'Full Rigged Ship', would have 6 yards on each mast. (Courses or Main Yard, Lower Topsail Yard, Upper Topsail Yard, Lower TopGallent Yard, Upper TopGallent Yard, and Royal Yard. To name just a few configurations.) There would then be numerous fore-and-aft sails. I know of at least one example of a ship which had 9 yards per mast, and which could set over 100 sails when 'under full sail" not counting Studdingsails.