Post by Tak To
Well, it seems that for a square rig, the lines that pull a sail
to the sides *and* down are indeed called the sheets. In other
words, there are just two out-and-down hauls (sheets) and not
two out hauls plus a number of down hauls and sheets.
No, the sheet doesn't pull the sail to the sides and down. It does
neither. It's purpose is to pull the corner of the sail aft. so the sail
is set and held at an appropriate angle to the wind.
For example, if a vessel, whether fore-and aft rigged or square-rigged
is sailing at an angle to the wind, its sails need to be trimmed
(sheeted), so that its aftermost corner on the side away from the wind
is pulled astern and held in that position.
It's hard to do pictures with text, but I'll try.
/ \ / Wind direction
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The picture is meant to be of a sloop sailing roughly at a 45 degree
angle to the wind. The wind is coming from the right side (starboard) of
the sloop, so the sloop is said to be sailing on a starboard tack.
Note the diagonal line in the middle of the sloop. That's meant to be
its mainsail. It's held in that position by the main sheet. The sheep
pulls the end of the boom, and the mainsail attached to it aft, and is
normally cleated down to hold the boom and sail in that position.
If the sheet weren't used to do that, the sail would flutter around
uselessly (luffing) and the sloop would make no progress. The sheet is
pulled aft until the luffing stops, the surface of the sail becomes
taut, and the sloop goes forward.
Much the same is true of the sheet on a sail on a square-rigger. I used
a fore-and-aft rigged boat as an example because it was easier to draw a
By the way, on a fore-and-aft rigged boat, any sail with a boom has a
single sheet, which can can be used pull the boom and sail astern to the
appropriate side. A sail without a boom (usually a jib) has two sheets,
both attached to the aftermost corner of the sail; only one of the two
sheets is used at a time, depending on whether the boat is on a
starboard tack or a port tack.
The square sails on a square-rigger also have two sheets, but they are
different from jibs. The two sheets are attached to the two bottom
corners of the square sail. Only one at a time is used, again depending
on whether the boat is on a starboard tack or a port tack.
If this confuses anybody, my apologies. It's hard to explain this
without being about to draw or show you real pictures.
By the way, I used to own a sloop.