The Physics of Surfing By, Reilly Stone

Surfing!! Surfing has become one of the world’s biggest hobbies and sport. Millions of people around the world surf. From longboarding to shortboarding, windsurfing to body surfing, or finless, there are many ways you can surf. But, not everyone knows the physics of it. In this slideshow I will explain the physics of surfing.

Intro Although you may not know it, everything you do surfing has something to do with physics. Newton's laws of motion,which describe the movement of matter, is a key factor maneuvering and staying afloat. Newton's first law states that objects in motion, like waves, tend to stay in motion, while objects at rest, like a floating surfboard, tend to stay at rest. This means you have to paddle in order to get a wave. According to Newton's third law, every action has an equal and opposite reaction. When you lean on an edge of the board, that edge pushes into the water, which pushes back up against the board. As a result, the surfboard turns.

Board Comparison Longboard - 9’0 or longer - more volume - more mass (~18 lbs) - more planing surface Shortboard - length (depends) ~ less volume - less mass (~6 lbs) - less planing surface Same density!

Catching a Wave Paddling & Catching a Wave - Surfer must accelerate to wave velocity using a combination of paddling and gravity. Longboard - More flotation ---> Greater paddling velocity ---> Catch waves earlier, before they break. Shortboard - Less flotation ---> Lower paddling velocity ---> Depends on gravity for catching the wave.

Bottom Turn The bottom turn is usually used right after you catch a wave. After catching a wave you ride down to the bottom of the wave then lean on your back rail (building pressure) then you slingshot right back up to the face of the wave (how much you slingshot depends on your board). Usually, the lower your center of gravity is, the more speed you will gain on the turn.

Noseriding A Nose Ride is one of the most difficult but most appealing move you can do on a surfboard. Although easiest on a longboard, it can be done on other surf craft The physics of a nose riding board differs greatly from the physics of any other type of board. The shape of the board must generate forces both upward and downward to create a successful nose-ride. Upward (in the nose) and downward (in the tail).

Turning When you lean on a rail to turn your weight with the power of gravity, sinks the rail slightly. Depending on how much you weigh or how much you lean, a turn will vary. The buoyancy caused by the board will let the board sink a little in the water but not all the way. Having a lighter board helps you to turn faster while, a heavier board gives more smooth slower turns.

Trimming Trimming is when used for gaining speed or as a transition for different moves. Trimming is when you stand on a spot on your board and stay there while the board accelerates for you. Usually when the front half of the board is almost submerged by the rider, that is the best place to trim from. It all depends on the weight of the rider the buoyancy and weight of the board and the wave.

Doing an Air Airs, most commonly performed on shortboards, are when a surfer and his surfboard get airborn off of the wave. After gaining speed on the wave, the surfer will go up to the lip and ,well, fly. How high depends on, the surfer’s weight, the board’s weight, the wave, and wind direction. Although I have never done one, they are very interesting.

Stalling Stalling is a move most commonly used when waiting for the wave to wall up, or for slowing down. When stalling you lift some of the board out of the water breaking its trimming surface area into a much smaller area, until you place the board fully in the water again.

THE END Thank You!!!!!!