The differences between a yacht and a boat lie in the length, purpose and expense of the vessels, and these distinctions sometimes overlap. A boat is a watercraft that is used for pleasure, commercial or residential purposes, whereas a yacht is used exclusively for pleasure and carries the connotation of luxury.
A boat is a watercraft that is less than 197 feet long from the tip of the bow to the end of the stern. A yacht is usually larger than 30 feet, but if it is luxurious enough, even a small boat can be referred to as a yacht. A ship is a watercraft over 197 feet long that can also be used for pleasure, commercial or residential purposes; therefore, a yacht can be either a boat or a ship, depending on its length. A yacht over 100 feet is referred to as a megayacht; one over 150 feet is called a superyacht. There are yachts as long as 400 feet.
The distinction between a boat and a yacht may be relevant for reasons such as buying and selling, ownership papers, or insurance coverage. Yachts tend to be more expensive, have more navigational equipment and be used for longer-range trips, and their insurance is accordingly more comprehensive and costly.