Out there on the water, there are two big forces working on vessels. The wind (when it blows) pushes on everything it touches — the bits of the boat above the water, and the water the boat is floating on. And the water itself flows and moves in three dimensions with the tides and currents and wind. The trick to getting somewhere in a sailboat (when you don’t have an engine) is to use your sails and rudder to make those forces work for you. The better you are at doing that, the sooner you will reach your destination.
The biggest challenge to moving a boat in water with just wind power is moving in the direction the wind is coming from. When the wind is coming from behind you, it will push you along in front of it. When the wind is right on the nose of your boat, it’s going to push you backward, of course. Surely, sailors have figured this out over the years, right?
They have, and the answer is to sail “off” the wind, but as close to it as you can if the wind is coming from where you want to go. That’s why sailboats zig zag. They’re cutting back and forth across the wind, switching their sails from side to side to work their way “to weather”. Some sail arrangements are better at doing that than others. Sails that line up along the center of the boat (most modern sloops, for example), help with staying on a close-hauled course. Square rigged vessels, where most of the sails are perpendicular to the keel (like a classic frigate), have a harder time.
So why have square-rigged sails? Because if the wind is pretty much behind you, you can throw up a whole ton of canvas and make incredible speeds to get where you want to go. The down side is, sometimes the wind will still blow you backward. Check out the plotted points for the brig Fawn on a voyage home from the Baltic in 1821 (see image above). The brig was traveling from right to left along that course.
How frustrating it must have been for the captain when his daily sightings showed they were headed back where they came from!