That is a boat hull that does not have a keel beam or a defined chine.
round bottom hull
the flat bottom i think
Round Bottom hull
flat bottom hull
Flat Bottom Hull
A round hull.
A round hull.
the bottom
This depends on the hull. Also is it a vee hull, semi vee hull, or modified vee hull? Deadrise (the angle of the vee on the hull bottom) and strakes (outward ribs running along the length of the hull's bottom) also plays a factor in the drag force. The best bet is to call the manufacturer to determine this.
Deep v. Round. Square. Multi hull
Barnacles
a Hull