Evolution and the Planning Hull

The image below is of a surfboard planning hull. Most surfboards are flat from end to end. A few have concaves and Vee's in the tail for speed and maneuverability. At lower speed the underside of the nose rocker, known as the bow in boating, pushes water forward and around the surfboard. The bow section is painted red in the picture. With the evolution of vertical surfing and flight, surfboards frequently land on its bow. This is due to gravity force and the angle of attack. At high speed, the flat bow cannot push water out of the surfboard's path fast enough. Water accumulates in front of the surfboard, in the form of a bow wave, and blocks movement. At the perfect angle, with the

Fluid Dynamics

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 t

Hydrodynamic Resistance

Speed on water generates resistance. Water resists compression. Water does not compress due to inter molecular hydrogen bonding. Bonding of hydrogen leaves little space between molecules. Without space, molecules cannot be compacted or squeezed together. Water molecules push back when high force is applied. This is hydrodynamic resistance or hydrodynamic lift. Water can be parted by slowly moving a finger through it. When speed is introduced water resists parting. This resistance is strong enough to break speed boats apart on impact. Water becomes as resistant as earth, and can shatter a boat into pieces. High speed impact with water will also catapult passengers and cargo., A chop o


There are many surfboard hull shapes; most can be classified into three categories. Each category has conditions which optimize performance. The first is the Planing Category. Surfboards which are designed to ride on the water surface are planing boards. These are generally flat bottom with or without concaves and channels for added lift. The flat bottom generates hydrodynamic lift with speed. This board works well in smooth conditions, planning on its tail. The flat bottom also performs as a wing, supporting a rider in flight. The flat bottom is not the best for high impact flat landings. The board can abruptly stop and cause injury to the rider. The second hull category is Displacem

Featured Posts
Recent Posts
  • Facebook Basic Square
  • Twitter Basic Square
  • Google+ Basic Square