On Twitter yesterday, I got to assist another writer with a few maritime navigational requirements. After all was said and done, I realized what a complicated set of information exists for boats and for boating. So, in the interest of being semi-useful, here's a primer on modern sailboats. Different rigging configurations have different names. 'Rigging' refers to the mast(s) and the shrouds (wires) supporting the mast(s). The diagram at left gives you the idea. Most sailboats you see in the US are Sloops - they have one mast which carries the mainsail, and one forward shroud that carries the headsail. The second most common sailboat rig is the Cutter. It has one mast, but two shrouds in front, allowing for two headsails. The third most common rig is the ketch. If you look at the diagram, it's tough to tell the difference between the ketch and the yawl. Here's the difference: On a ketch, the shorter mast is stepped forward (in front of) the rudder post (where the rudder attaches to the boat). On a yawl, that mast is aft (or behind) the rudder post. On the west coast of the USA, I have never seen a yawl. Plenty of ketches. Not a single yawl. It's possible that you'll see a few yawls on the east coast.
What's the point of all the different rigs? Flexibility. A cutter has more sail plan options than a sloop. A ketch has yet more sail plan options. The trade off is that you have to carry more canvas (sails) the more options you have, which means more weight and more messing with sails. Sloops are popular because they're relatively easy. Most sloops carry four sails, a main, a jib (smaller, for lots of wind), a genoa (bigger for lighter wind) and a chute (or a spinnaker - the big, colorful sails you sometimes see flying way out in front of a boat - these are for running down wind only). Cutters and ketches carry more sails than that.
The type of boat you put your hero and heroine into depends on how they intend to use the boat. In brief, sailboats are divided into three kinds of uses: Day sailers, Coastal Cruisers and Blue Water boats. Day sailers are just that - smaller boats meant to be taken out in reasonable weather just for the fun of zipping around on the water. These boats are usually 25 feet in length or less. They have fewer amenities. Coastal Cruisers are boats of any size, though usually between 25 and 40 feet, designed to let you sail from port to port. They'll have things like berths (beds), a head (toilet) and a galley (kitchen), but they aren't designed for ocean crossings. People DO cross oceans in coastal cruisers, but the boats aren't designed specifically for that. Blue Water boats are built to cross oceans. They can be any size, but the construction is heavier. They tend to be slower boats as a result. But they're designed to handle just about anything (please note the 'just about') the ocean throws at them. These boats have berths, a galley and a head. The cookstove will be gimbaled (put on a series of pivot points so it stays relatively level regardless of wave and boat motion). Inside an ocean going sailboat, you'll likely find teak hand rails in the headliner (hooked into the ceiling). As a whole, these boats have more tankage - bigger water tanks or they have a water maker to keep fresh, drinkable water onboard. Some world cruisers swear that crossing an ocean in anything smaller than a 40 foot boat is uncomfortable, though plenty of people do it.
As you may imagine, cost increases as you move from Day Sailer to Coastal Cruiser to Blue Water. It isn't merely a function of how big the boat is, either, but that's a post for another day. Next up: How sails work.
Image Source: http://www.answers.com/topic/sailboat-rigs