The following video is a simulation of a ship hull pushing water out of its path as it moves forward. The ship's bow parts water and pushes water aside in rough seas. A ship's speed is restricted as its bow always pushes water. Waves part and move around the ships hull assisting forward progress. Simulated waves change direction moving against the ship at first then with the ship later.
A speed boat planes on the aft half of its underside, with its bow out of water. The bow is vulnerable to high impact with high speed. At higher speed in larger waves, speed boats decelerate to avoid flipping. An impact can be hard enough to stop and damage a speed boat. The speed boat often leaves the surface at high speed and lands hard. Water resists parting with speed
The tipping of boats with a higher center of balance demonstrated in the previous video is similar to a surfer standing on a surfboard. Although a surfboard is unstable at lower speeds with an upright surfer, it becomes highly maneuverable. The surfer can carve hard turns by leaning and shifting his weight.
A flat bottom boat rides on the surface and is efficient in smooth clean conditions. The following video demonstrates the differences.
Like boats, flat bottom surfboards perform best in smooth water. They plane on their aft halves like a speed boat. When the bow impacts water at high speed, movement can abruptly stop, launching its rider. Many of the wipe outs featured in the next video are the result of a flat bottom board impacting water at high speed, often after a board gets airborne.
Surfboards are leaving the water and landing flat. Flight has become a part of surfing. This evolution requires a different bow shape being round, vee, or a combination of both.
The playing field has changed forever.