Nose Poke Part IV/High Surf + High Nose Rocker = High Risk
The WSL Big Wave Tour Peahi Challenge featured innovative performances. In the final, Ryan Hipwood and Kai Lenny together, took off late under the lip on a giant wave. Take offs under the lip are usually attempted in waves of less magnitude.
Both surfers initially free fall; their boards impact the wave's face. The impact generates splash and spray in both rides. Spray flies over Ryan's board. In Kai's ride spray shoots to the side of the board. This difference produces opposite outcomes.
The boards land on their bows; the splashes are bow waves. Bow waves are not visible, but; the red arrows indicate the origin of the spray. Ryan is in a more vertical plunge, evident by the angle of his board. The steep angle of attack causes a harder impact, due to gravity force. This can be proven in an Inclined Plane calculation, from earlier posts. Ryan carries more gravitational force. Kai makes a more level landing in comparison; his bow is able to push water aside to keep the board moving. Water shoots to the side of his board. Spray shoots over Ryan's board and around his knees and continuing over his body. Unlike Kai, due to the angle of attack and speed on impact, water cannot move directly out to the side. Water moves forward, downward and upward before moving around the board. The sudden impact builds water or a bow wave which blocks and decelerates his board.
Due to the acceleration Ryan carries, water must move rapidly and efficiently, out of Ryan's way. Water accumulation and blocking occurs instantly, especially if the bow is flat. The sudden impact builds a bow wave in front of Ryan's nose, which abruptly halts his board. A large difference in impact is where contact occurs. They land on different curvatures of the bottom nose rocker bend. Ryan hits where the bend protrudes into the water line. Spray continues to flow over the nose of his surfboard.
Kai's landing being a little flatter, avoids hitting the curved underside of the nose rocker. Kai continues to move with his board displacing water to the side.
Bow shapes which displace water directly, can also cushion impact. This reduces the chance of launching a rider with an abrupt stop. The more nose rocker the board has, the more water it must displace when it makes high impact. At high speed, high nose rocker and a flat bow risks a catapulting nose poke. Ryan sustains an injury from his wipe out, which hindered his performance.
Photos and video from youtube.com. WSL Big Wave Tour/ Peahi Challenge