What is the term for the depth of the water needed to float a boat clear of the bottom?

The term for the depth of the water needed to float a boat clear of the bottom is called the "draft" or "draught" of the boat. The draft is the vertical distance between the waterline and the bottom of the hull of a boat. It is important to know the draft of a boat in order to ensure that there is enough water depth to safely navigate and avoid running aground. The draft can vary depending on the design and size of the boat, as well as the weight of the cargo or passengers onboard.