BOATS AND MOTORS 2 Boat Terminology Draft - the vertical distance from the bottom of the underside (the keel) to the water line. The draft determines the minimum depth of water in which your boat can operate-the larger the draft, the deeper the water must be for the boat to operate without running aground. If you're new to boating, there are many new terms, procedures, and rules to learn. This lesson will help you become familiar with the words and terms that describe parts of the boat and directions on the boat. Many of these are critical to safety. We will discuss a few of the most important terms in this lesson. Freeboard - the vertical distance from the waterline to the upper edge of the boat's sides. Boats with low freeboard may take on water in rough conditions or when crossing another boat's wake. Boat Measurements Centerline - an imaginary line drawn from the bow to the center of the stern along the middle of the boat. Length or Length Overall (LOA) - the distance from one end of the boat to the other end. It does not include outboard motors, brackets, or other attachments. Waterline length - the length of the boat from end to end when it is in the water Beam - the width of the boat at its widest point. Trim - The angle at which a boat rides in the water. A boat may be trimmed so it rides even, down at the stern, or down at the bow. Displacement-the weight of water that the boat must push out of the way to float. As you add gear or passengers, the boat's displacement increases and the boat sinks lower into the water. Knot - a measurement of speed on the water equal to one nautical mile per hour (1.15 mph). 4