The most important parts of a boat are arguably the rudder that steers the boat, the propellers or sails that drive the boat, and the frame and shell of the boat called the hull and keel. Other important components of a boat include the chine, stern, tiller and mast. There are many different types of boats, and the importance of their parts may vary.
The hull of a boat is the internal frame that gives the boat its shape. It is usually covered in metal or fiberglass. The spine of the boat that runs along the boat's bottom and center and juts out at the bottom to prevent the boat from tipping over is called the keel. Without the hull there would be no boat, and without the keel it would not float properly.
Without the tiller and the rudder, it would not be possible to steer boats that do not have a motor and steering wheel. The rudder sits in the water, and it is controlled with the tiller, which is comparable to a car's steering wheel. A sailboat has a mast, which is a long pole that holds up the mainsail, which is the largest sail that catches wind and propels the boat. The jib is a small, triangular sail that provides extra power.