Coaling from a Collier, something that isn't done these days. It's important to remember the old saying one hand overhauling the clewline is worth a dozen on the sheet, especially if you have any idea what it means. So far I have discovered that overhauling is to haul a fall of rope through a block till it is slack, a clewline is a rope that runs from the bottom corner of a square sail to the yard and is used when reefing to pull the corners of the sail up to the yard, and a sheet is a rope running from the clew to the deck and is used to trim the sail when its angle to the wind has been adjusted by moving the yards. So, I'd guess that what the saying means is that more can be achieved by a small amount of properly applied effort than a lot of brute force, one person slacking off the rope holding the clew is worth twelve trying to pull the clew down with the sheets?