Polynesians traveled throughout the Pacific in dugout sailing canoes. They navigated through storms and high seas, plotting their paths relative to the Sun, Moon and stars. Polynesian did not have a written language, however; their early teachers embraced Science. Navigators utilized science to navigate and find tiny islands in a vast ocean.
Calculating the strength of wind combined with ocean currents, they successfully sailed against and with large ocean swells. Polynesians well understood Physics, the science of matter moving through space and time. Using this knowledge, their artists built stable double hulled canoes, like the Hokulea a proven replica. They also built ancient surfboards.
Surfboards and canoes were hand crafted by artists with primitive stone tools. Hawaiians tapered surfboard noses to a blunt point and rounded the sides or rails, features used in modern surfboards today. Ancient surfing was a sport for chiefs who rode surfboards 16 feet in length. Commoners used smaller surfboards called Alaia, but; could not enter the better surfing spots reserved for royalty.
During the short board evolution, modern surfing was born. This was an era of change, artists innovated and improved surfboards. They discovered a smaller board, some what like the Alaia, planned well on a wave, and increased maneuverability. High performance equipment produced modern surfing. The low rail shape or flat bottom design emerged during this period. The flat bottom is a popular design today and has been the primary bottom shape for almost 50 years. The flat bottom surfboard is truly a board. The bottom is flat like a wooden plank, except for the upward curve in the nose area. The upward nose bend is called nose rocker, as it mimics the curved wooden rockers of a rocking chair.
Nose rocker keeps the surfboard from diving underwater and stalling, commonly called pearl diving or pearling in surfer jargon. Rocker forms a bow on the underside of the nose. The bow is usually out of water when a surfboard planes. When the bow contacts water it pushes water aside, displaced water is called a bow wave. The surfboard follows in the path cleared by the bow and gains speed until it planes, then the bow rises above the water. Science calls this hydrodynamic force or lift. Daniel Bernoulli discovered this principle in the 1700's, hence; it is called the Bernoulli Effect. High pressure induced by speed, produces lift under a flat surface. Hydrogen atoms in water bond strongly together making it cohesive. When flat surfaces impact it at high speed, water resists parting. On the other hand, water parts very more easily with pointed or round objects.
Surfing is evolving as surfers incorporate flight in their rides. Surfboards fly in aerial maneuvers and fly down the face of very large and steep waves. When the surfboard gets airborne, the bow often becomes a landing pad, due to gravity. At high speed, the bow can make hard impact in the wave.
In a hard landing, water cannot move out of the way fast enough with a flat bow.
The flat bow can create a negative force against the forward thrust of a flying surfboard. This negative force is visible as a bow wave which forms directly in a flat board’s path. At the perfect angle, the flat bent bow can produce a counter force, abruptly stalling and pitching a surfer. The force is hydrodynamic lift, resulting again from high impact on water with a flat surface. Hydrodynamics can work against a surfboard. The wipe out is identical to a pearl.
Surfboards in the past, had round bows with higher rails. Duke Kahanamoku had a few boards with rounded bottoms. This design parts water and moves it out of the rider’s path. A surfer may ride further after a hard landing. I am now experimenting with bow shapes that are more boat like and less like a flatten board. Ancient knowledge is very relevant today.