Nordhavn 40/II - tawler:
Beam: 14' 6"
Draft: 5' 2"
Hinckley T40 - jet boat:
Beam: 12' 5"
Draft: 2' 3"
I would say that these are the extremes. A semi displacement hull would run anywhere between these two.
The average draft of a 30-foot boat typically ranges from 3 to 5 feet, depending on its design and purpose. The beam, or width, usually falls between 8 to 10 feet. These dimensions can vary based on the type of boat, such as a sailboat or powerboat, and its intended use. Always check specific manufacturer specifications for precise measurements.
a boat draft
Beam...the widest part of a boat
The beam of a boat is the measured width of the broadest part of a vessel
The definition of beam is the widest part of the boat
that is where the water level is when the boat is in the water.
The measurement of a boat is commonly referred to as its "dimensions," which typically include length, beam (width), and draft (depth). These measurements help determine the boat's size and capacity. Additionally, "tonnage" can be used to describe the volume or weight capacity of the vessel, often measured in gross tonnage or net tonnage.
The term you are referring to is "draft". The draft of a boat is the depth of water needed for it to float clear of the bottom.
transom
It is the boat's draft.
The distance between the bottom and the keel of a boat is the draught (British English).
To calculate the draft of a boat, measure the vertical distance from the waterline to the bottom of the hull (keel) when the boat is in the water. This measurement can be taken using a sounding line or by checking the boat's specifications if available. The draft can vary based on factors like load and water conditions, so it's important to take measurements under typical operating conditions. Additionally, ensure that the boat is level, as an uneven load can affect the draft.