If you have read and learned the first three lessons here then you already know the basics. Congratulations! All the rest is frippery. Now you have the rest of your life to wallow in the minutae.

The sails catch the wind (duh). You could argue ad infinitum about the proper shape. Sailors are forever tweaking the sails when underway to try and get the most power out of them. Enough about that.

Nowadays, almost all sails are triangular in shape. Each corner of the sail has a name:

Head- top
Tack-bottom
Clew- the other one

Also, each side of the sail triangle has a name

Luff -leading edge
Leech- trailing edge
Foot- bottom

You have to learn these names. Otherwise you won’t be able to communicate well with your crew members when underway, and mayhem will ensue.
you need to crank down on that thing there so that the thing isn’t flapping and causing that thing to come unhooked from the thing…

Here is a handy mnemonic for remembering the parts of the sail “Captain LUFF had a TACK in his FOOT, but he didn’t have a CLEW that there was a LEECH on his HEAD! 🙂

also helpful to know the ropes-
halyard- hoists the sail
sheets- control the sail
outhaul- stretches the foot of the sail
lazy jacks- lines that keep the sail in an orderly bunch when you drop the sail
topping lift- a line that holds the boom up off the deck