Quantum Surf Physics
Scientific Surfboard Design Study
Introduction to Fluid Dynamics
Archimedes, a third century B.C. Greek Mathematician, discovered that a body will displace a volume of water equal to itself to float. Buoyancy or the upward force, is equal in weight to the water it displaces. When a body moves in water, it takes the place of or displaces water from the space it formally occupied. Therefore, in order to move in water, a body must move water equal to its mass. The principle applies to vessels such as ships and schooners whose hulls extend deep below the visible water line. These vessels are speed restricted because they are always pushing water in the form of a bow wave. They cannot move fast enough to pass the bow wave, which their submerged hulls create. This is in contrast to speed boats which sit higher on the surface and can accelerate faster than water can move. Water needs time to move, and speed does not allow fluid time to move out of the body's path. Water resists penetration by speeding bodies and provides support or lift to speeds boats. These boats ride on the surface and create a trailing wake but no bow wave. Their speed is not restricted. Surfboards plane in this manner with speed providing hydrodynamic support. Surfers are supported by their speed on water. Water takes on an impermeable characteristic with speed.
As an example take skipping a rock on calm water. The rock must be flat to skip. A flat surface resists penetration into water with speed. This is known as Bernoulli's Principle. Speed generates upward pressure known as hydrodynamic lift. When speed diminishes the rock hits water and sinks. A surfer also sinks when he loses momentum. Surfers lack a power source; an abrupt stop usually ends their ride.
A flat surface can also abruptly stop movement of speeding surfboards with high nose rocker. The bend in surfboards exposes the nose underside to high impact in a freefall drop or high speed impact with chop. The area shaded red in the illustration is a common area impacted at high speed.
Hydrodynamic lift in the nose area, especially if the underside is flat, can push a surfboard backward or abruptly stop movement. A surfboard that is flat from nose to tail, as the one pictured above, optimizes lift by preventing water penetration at high speed. When pressure is applied to the nose in a dive, it resists penetration and generates pressure in the opposite direction. This is what causes a surfboard to stop in a high speed poke or pearl dive. A slow or gradual nose poke can be ridden through successfully. A deep dive below the surface will not recover. A shallow dive may recover on a surfboard with a round or VEE-like bow and less nose rocker may. The proof is in archived videos of our past, available in article. High nose rocker is successful when the underside does not impact water with force.
The photo below is of a surfboard in a shallow pearl or nose poke, the arrow indicates hydrodynamic force slowing forward movement. The nose is distorted due to light refraction. The bend in the bow is producing drag. Water over the top of the board is not a factor. It spills above the deck in an eddy. Pressure from the top is generated by the surfer's weight and speed, not water. Instead of preventing a nose poke or pearl dive, nose rocker can increase its chances. A high speed impact on a flat bottom with high nose rocker, can stop movement and catapult a surfer.
Both Archimedes' and Bernoulli's principles are discussed in depth later.
A Tragic Loss Can Save Many
RIP Mark Foo photo Bob Bobour/video available from youtube
Mark Foo left us long before the introduction of inflatable life-saving devices and jet ski support. Inflatable vests were developed after near-death experiences. Before surfers partnered with skilled jet ski rescue drivers, a surfer in distress was on his own. These safety precautions were introduced after many near-drowning experiences. Mark's death also led to a discovery that can save others.
Fellow legendary surfer Brock Little studied videos of Mark's ride and said, "He hit something". Mark fell after the underside of his surfboard nose, impacted the wave in a very steep drop. Nose rocker creates a bend in the surfboard bottom. At high speed, an abrupt impact on the bend can launch a skilled surfer. The underside of the bend is called a bow in boats. The boat bow is what impacts water in rough seas. Henceforth the realization: A surfboard may ride through a shallow dive if its bow is not flat and rocker bend is not severe. Flat bottom boats only perform well in flat water, where they do not buck swells or chops. If this theory is applied to surfboards, fewer surfers may be catapulted.
With a Final Breath
Mark Foo loved the ocean and the surfing lifestyle, his quotes expressed his love and commitment: "Surfing and Martial Arts are really similar. If you're into it, it's a way of living, a lifestyle. You live it; you don't just do it. My life is surfing." Surfing was Mark’s life as well as his career. He produced a TV series dedicated to surfing called H3O, his acronym for heavy water. Ironically, heavy water may have attributed to his demise. Science can prove that cold water is denser, heavier, and thicker than warm. A surfboard does not move through cold water as easily as warm. This difference is not significant at low speed, however; at high speed, the temperature may be a factor. Coldwater also affects the human body by restricting movement, making breathing difficult and slowing circulation. Thus cold water is more dangerous than warm Hawaiian water.
On December 23, 1994, Mark got off a flight in San Francisco, from Honolulu. He went directly to a very dangerous surfing spot known as Mavericks. The waves were beautiful, not exceptionally large, but deceptively inviting. Videos show Mark smiling as he entered the water, not knowing the dangers that lay ahead. He caught a warm-up wave and the nose underside or bow of his surfboard stuck. Mark successfully rode out of a shallow nose poke and intended to heed its warning by changing boards. When he disappeared friends assumed he went in to change boards. Mark did not make it to the beach as the bow stuck again on his next wave, this time with a harder impact. The board abruptly decelerated and launched Mark in the air, with his final breath.
Mark once said, "The life I've had has been good enough that I can die happily. Surfing's done that; surfing's given me that. So I can accept dying while I'm surfing." No one really knows how Mark drowned. There is speculation that he hit the bottom, but; it is not known when he hit. A bottom collision may have occurred after drowning or possibly led to drowning. An autopsy revealed some plaque buildup in his arteries. In warmer conditions plaque may not be a deadly issue. Blood circulation is restricted in cold temperatures by constricting veins, conserving blood for organs. When veins constrict with an interior build-up, blocked circulation may cause a loss of consciousness. Common dangers can become deadly in cold water.
Mike Parsons, a fellow big wave surfer, caught the wave immediately after Mark’s and wiped out. Mike says he bumped into another surfer while violently churning in the cold icy water. He later realized that he collided with Mark. This confirms that Mark experienced a two-wave hold down, and was likely still alive at their encounter. Mark did not surface, true to another quote that became his epithet, "If you want the ultimate thrill, you've got to be willing to pay the ultimate price." The truth is, using Mark's experience we may avoid paying the ultimate price.
Learning from a Wipeout
We better understand joy by experiencing grief and pain. A surfer's joy from a successful ride through a long hollow wave, is exhilarating after many wipeouts. A wipeout, although painful, is not failure. A wipeout is a phase of learning.
In a fall into the water, your body pushes water aside softening the impact. When you break the surface, water parts and moves from under your body as you decelerate. Your energy is transferred to the water as it provides layers of mattress-like support. Water cushions you in a low fall, but not in a fall from a great height. The higher the fall, the greater your speed. With a fast-moving body, water cannot move out of your way fast enough. When water cannot move, it provides a block known as hydrodynamic resistance. The same force that supports a speeding surfboard on the surface, stops your speeding body.
You can hit the water by launching from a speeding surfboards, so hard; that you hurt. Pain and even injury may occur when hydrodynamic resistance momentarily blocks your entry into and through water. The speed you carry from a diving surfboard, will cause you to briefly stop on the surface. Water does not move much with impact by speeding, flat objects. Water cannot compress, therefore; your body compresses. The water feels more like the earth with high impact. You can reduce resistance by landing in a dive or pin drop fall. This will reduce chances of you skipping on the wave surface like a flat rock. Unfortunately, these measures may cause you to hit the reef.
After a hard numbing collision with water, your body decelerates by compressing against water before penetrating the surface. The collision possibly wrenched your neck and vertebrate, this will hurt later. Your tissues and organs also took a jolting blow, when the water's surface did not give in. You probably feel a bit dizzy from a numbing blow to your head. As you come to your senses, you yearn and crave air, your lungs flattened and released the little air they held. Just when things start to calm, there is a roar and a thundering explosion. The wave breaks on you with a brutal and violent force that squeezes your sinuses and eardrums. They feel like they will burst. Water twists and bends your body into unimaginable shapes. You experience the forces of hydrodynamic resistance. It is hydrodynamic forces that bend and twists you. You are propelled against water moving all directions, straining muscles and joints as well as more distortion to your flesh and organs. The violent turbulence subsides and you feel weightless as you are sucked upward, and pitched over a large powerful waterfall. You land in turbulent frothing water still craving a breath of air. After a long struggle, you find the surface and take a deep breath, You can only take one breath as the next wave is about to break on you. You dive under for another beating, your body limp with exhaustion. You are fortunate, you are alive, Mark Foo was not as lucky. Mark experienced the beating twice with a two wave hold down in very cold water. Cold water is another danger factor discussed below.
The same hydrodynamic forces that causes injury and harm in a wipeout, can cause your surfboard to stop in a nose poke. Hydrodynamic force when applied to the bent nose of a surfboard, at high speed can block movement and pitch a good surfer. Pearling and nose pokes have been a problem for surfers since the first Polynesian rode a wave. All surfers have experienced nose pokes or pearl dives and know the feeling of being catapulted through the air, when their boards abruptly stop. Nose pokes have increased with aerial maneuvers and free fall drops. There is a solution for this, one which may have prevented Mark's wipeout. Note the nose rocker of Mark's surfboard below. It is typical of many surfboards in this era. High nose rocker was very popular in the 90's. The design prevents nose pokes, only if the underside does not contact water at high speed. In a free fall, impact to the flat underside, prevents penetration and creates lift. The force momentarily and abruptly stops movement, catapulting the rider. Reducing nose rocker or modifying the nose bottom shape will reduce nose poke catapults.
Hawaii's Fallen Surfers Shape the Future, RIP
Mark Foo left us an important revelation. It was not realized until 2013 when Kirk Passmore disappeared. Kirk was surfing at Outside Alligator Rock, with its deadly reputation. This is sadly where Todd Chesser perished. Kirk likely burst an eardrum and lost equilibrium after a crushing wipeout. He was last seen kicking his legs in the air, trying to swim the wrong way, toward the bottom. Both Mark's and Kirk's last rides were recorded with similarities. Kirk’s father allowed his son’s trailer to be posted on the internet. His gesture helped realize a discovery that may save others.
Warning: The following feature may be disturbing. The surfer's wipeout ended tragically. The trailer is made available by the surfer’s father, on youtube. Take a moment to remember Kirk Passmore. In the blurry image below, a chop is visible below his board. It is producing drag and generating a plume of spray. Seconds later the surfboard stops without submerging below the water line. Kirk is catapulted and the wave breaks on him.
During the passage of time between the tragic events, surfing changed. Successful airborne maneuvers and controlled free falls became common, as surfing evolved. Surfers were very successful flying at lower speeds, in small to medium waves. Progress came with a price, airborne surfers were enduring many bad wipeouts and injuries, due to hard flat landings. Surfers were injured as they pushed their equipment to performance limits. Thus a revelation was born, flat bottom surfboards with high rocker can stop in a high-speed landing. Modern surfing has taken the flat bottom as far as it can go. Extreme nose lift combined with a flat bow, can stall a speeding surfboard and pitch its rider. Mark's wipeout is the result of a flat bottom surfboard, making a high impact on water. The flat bottom does not always recover from a flat landing, at high speed. This is especially evident and common in colder water. Many examples of wipeouts at Mavericks are featured in this article. Cold water is denser than warm and more difficult to displace at high speed, according to Chemist Barrett Stoller. An analysis and explanation follow.
In 2011, a second beloved Hawaiian surfer drowned in Maverick's cold and violent waters. Sion Milosky, a well respected big wave rider, succumbed in a two-wave hold down, after a long session at Mavericks. Sion, a loving father of two daughters once said, "My wife, my daughters, they're what I live for." Many near-drownings occur at Mavericks, but; two deaths both Hawaiians may be more than coincidental.
Again another tragedy shocked Hawaii in 2015, not in the surf but in Lake Tahoe. Hawaii student Marc Ma, went stand up paddling with a group of college friends, in the cold Lake. The group got in trouble when gusty offshore winds strengthened, sending everyone further and further from shore. All were exhausted and approached hypothermia. Marc was the most experienced paddler in the group. In the true Hawaiian spirit of Eddie Aikau, he set out to get help. Wearing only shorts he battled the chilly wind and freezing spray. Marc was a member of his college football team; he was fit and in shape. Like Eddie, he disappeared seeking help and was not found. Rescuers spotted him but had to save the group first. When they went back for him, Marc was gone. We are certain that Marc went in peace, knowing the others were safe. He gave everything he had to help his friends and could do no more. Marc spared nothing, but; cold temperature took its toll. Expending all his energy in cold conditions may have caused a collapse due to exposure and fatigue. Marc Ma was the third Hawaiian to drown in cold water, following Mark Foo and Sion Milosky. The three loses brought awareness to the importance of cold water conditioning.
Hawaiians are not acclimated to cold water. They are well experienced in dealing with long hold-downs, extreme winds, and rough water, but; these situations become life-threatening when the temperature drops.
Our autonomic nervous system diverts blood circulation from arms and legs to our organs in cold temperature exposure. Organs continue to function but, limbs needed for swimming and survival become numb and useless. Regular exposure to cold water increases endurance and acclimates surfers and swimmers to colder environments. Casimir Pulaski, a conditioning expert, explains that surviving a perilous condition is dependent on cold water conditioning.
In the following video, Johanna Nordblad swims under the ice for 50 M without a breath. She is conditioned to her environment. Conditioning aided her recovery from a bad accident. Coldwater conditioning has other benefits: increased metabolism improved circulation and fortified immune system.
Surfboard Design Study
Surfing is constantly evolving. Recent accomplishments in large waves and success in aerials exceed the achievements of past eras. Surfers are riding waves, bigger than anything ridden in the past. Performance increased, speed increased, and aerials improved. The higher and steeper the drop, the greater the speed a surfer attains. Surfers are flying above waves through the air. This introduced hard flat landings to surfing. Many ending in horrible wipeouts. With progress came injuries and fatalities.
At lower speeds, the flat bottom surfboard with low rocker performs well. Surfers complete aerials in smaller waves on flat bottom boards, moving at lower speeds. Surfers cannot remain on their feet in an abrupt flat landing that abruptly stops a surfboard. In big surf, a long flat surfboard with high rocker, can suddenly stop and pitch the surfer in an airdrop.
Most vessels move water in order to move. They constantly push water limiting their top speed. Speed boats and surfboards attain a speed where water underneath it cannot move out of its way. The speed makes water somewhat impermeable so speeding vessels ride on top of it. These vessels are no longer supported by buoyancy alone. The hydrodynamic lift created by speed supports them.
Water needs time to move this is called transition. Speed removes time, and momentarily prevents water from moving. Water is trapped both under and in front of speeding objects. When water cannot move out of a speeding vessel's path, it generates resistance. Hydrodynamic force may be generated laterally and vertically. Lateral force affects forward speed. Vertical hydrodynamic force provides lift. Both are produced by water pressure induced by speeding objects. Hydrodynamic force is not produced by moving water, but instead by speeding objects generating pressure on the water.
An example of what happens is demonstrated when a paddler inserts his paddle broadside, into the water from a moving canoe, kayak, or paddleboard. The vessel decelerates and turns at a slower speed. Water flows around the paddle and decelerates one side of the vessel causing it to turn. The force generated against the paddle is hydrodynamic pressure. At lower speed, the paddle can control direction by controlling water flow. If a paddle was abruptly thrust into the water from a vessel speeding on a wave, it may push the paddler back. At high speed, water cannot move around a flat paddle expediently. The paddle is blocked by hydrodynamic resistance and pushes back against the paddler.
Movement through water by boats and ships with submerged hulls also produces hydrodynamic resistance. They generate drag similar to a paddle stuck in the water. These vessels lack the power to plane on the surface and constantly push water. This restricts their top speed and is known as Wave-making Resistance.
A paddler on a surfboard in a wave-less ocean is restricted in speed by Wave-making Resistance. A paddler, without a wave, lacks the power to generate enough speed to fully plane on the surface. He generates resistance against his surfboard bow with each stroke. His top speed is restricted similar to sailboats or large ships. Movement through water is accomplished by moving water. Hydrodynamic pressure pushes against a vessel's bow when it moves. This creates a bow wave and restricts speed.
Speed boats do not have this restriction. Boats with planing hulls and power can rise above Wave-making Resistance. Speed boats or planning boats ride on the surface hydrodynamically. Resistance on the bow is eliminated when it lifts out of water. This transition is gradual as water needs time to displace. Upward lift supports the vessel on its aft half, once sufficient pressure and speed are attained. At this point, only a trailing wake is produced. The bow wave disappears when the boat is fully planning. A surfboard gliding down a wave, planes on the surface similarly. Surfboards also need time to transition to planing. Surfboards push water until it gains sufficient speed to ride on the surface. When surfboards stop due to hydrodynamic pressure against its bow they often stop. Unlike a boat, they cannot generate momentum without an engine.
Another example of upward lift is the support water provides when we dive into it. As you penetrate water in a dive your body pushes the water out of your path. Water pressure against your body is hydrodynamic force. Your energy is transferred to water in the form of waves. You generate waves, slowing and descending deeper until your energy or speed dissipates. Descent into liquid is only possible, if the medium has time to move out of your way.
Should you fall into water from a ledge several hundred feet high, you will hit water carrying great speed. Water cannot move out of your way in time to allow penetration. You will momentarily stop on the surface, blocked by water until you decelerate. Water cannot absorb your impact, your body must take the crushing blow. Depending on how you land, you may sustain injuries.
Water supports you briefly, on the surface with hydrodynamic resistance. Water cannot compress, due to the intermolecular bond of hydrogen atoms. There is no space for molecules to compress. Water becomes more like earth to speeding objects. In high impact with water your body compresses.
As with falling bodies, fast-moving surfboards plane because water under the board is unable to displace. This develops high pressure against the surfboard bottom, similar to pressure from the impact of a fallen body. Water pressure under a speeding surfboard and provides support. The surfboard is no longer supported by buoyancy alone. Speed keeps it from sinking or penetrating the surface deeply. Water cannot be displaced by a speeding board fast enough to allow it to submerge. Thus a surfer can stand up and ride a moving surfboard supported by resistance or lift.
Speed lifts a surfboard by creating higher pressure on the bottom that exceeds top pressure from the surfer's weight. Daniel Bernoulli, in 1738, discovered that speed directly affects pressure in fluids, including air. He experimented with blood flow, often painfully tapping into a patient's arteries to measure blood pressure. This was before blood pressure monitors were invented. Bernoulli's formula proves that pressure is proportional to velocity squared.
Nose rocker produces a flat bent underside or bow, which creates lift by resisting deep penetration of water's surface. The flat surface resists water displacement. In a dive, it attempts to stay on top by blocking water. Pressure on a bent surface pushes the board back. Much like a paddle, a negative force or braking action is generated and is visible as spray. A bow wave forms directly in a flat surfboard’s path, blocking its progress. This block may be significant in depth due to cohesion. A flat bottom may push against a formidable wall of water.
When a speeding board suddenly hits the wave bottom, the flat bottom board abruptly stops and pitches the rider. This often occurs in free falls and aerial landings. The flat bottom cannot transition, instead it blocks movement. A round or Vee bow can absorb impact an allow the board to transition gradually to a lower speed.
The following trailer features Dave Wassel, veteran big wave rider. He either hits chop or the wave face, after the nose is lifted into the air by wind. A screen shot from the ride, is posted below, from Surfline.com, Dave looks positioned to make the drop. Look closer, his trailing wake is broken. There are tiny gaps in the trail, which suggests that the board left the wave, airborne. Note also the wake coming from under the front of Wassel's board. It shoots knee high spray over the board. This evidence suggests the board fell and landed flat. This generated a forward wake under the nose. We cannot see how water is moving under a surfboard. Wake and spray are clues to what water is doing. Physicists discover planets by studying irregular movement of nearby specks of light. Water spray may reveal resistance or drag. The spray also suggests that Dave's surfboard is flat. Further explanation is forthcoming.
Surfline.com surfline tv greatest wipe outs.
Shane Dorian survives a terrible wipeout after encountering chop at Mavericks.
Note spray shooting from under the nose of Shane's board. Youtube
Next feature, Shawn Dollar’s board sticks and stops on the surface. It pearls after he is launched in the air. The rocker bow or bend in the nose stops his ride. Spray shoots from under his board as it pushes water. See link to Surfline.com surfline tv greatest wipe outs.
Flat Bottom Surfboard
The flat bottom surfboard is the most successful surfboard design, in recent surfing history. It has been the standard for well over four decades. The flat bottom is used in over 90% of surfboards, and 75% of standup surfboards ridden today. The flat bottom is a planning hull, riding on the water line. This hull is combined with V’s and concaves, in the tail, to increase control and speed.
The surfer’s skill is an important factor. He must maintain his balance and adjust his weight to control the board. The surfer must do everything perfectly. All featured riders are excellent surfers. The wipe outs are due to the extreme conditions and limits of equipment. Surfers rarely blame their boards for a wipe out. They do their best on any board they ride and more often blame themselves for failure. Surfers can keep the bow out of water with their skills and control. Control is compromised at high speeds and when the board leaves the wave in the air. They can drift their fins and slide to the bottom. In a free fall drop back side, riders can absorb impact with their bodies and keep the bows from sticking. John John Florence and Andy Irons demonstrate their techniques in successfully free falling into steep waves.
Skilled surfers absorb impact with their bodies to keep the board moving in a hard landing. Weight is taken off the board as the surfer’s body slams into the face of the wave. The weight removed from the speeding board, prevents the bow from hitting hard and stopping. With skill and their backs to the wave, surfers also break their fins and free fall or side slip down a steep wave. This gives an advantage to back side surfers in extremely steep waves. Backside surfers not only unweight their board, but; stall deeper in the barrel by dragging their butts. This is not an easy task and requires skill as the following video demonstrates.
Setting an Edge
The flat bottom was developed during the single fin era. The edge or corner produced by the flat plane intersecting the rail, held a steeper wave. The wide point of surfboards were further forward of center. Riders planed riding further up on their boards. The single fin combined with the harder and longer edge held the board in the wave. The board would not roll or slip down a steep wave. Multiple fins on modern boards can also hold a steep wave, allowing a softer rail. The edge may be maintained from the tail to the nose, fading at the bow area. This will help keep the rail in the wave.
Next:The spray shooting from under Mason's board is a sign of resistance. The board is pushing water and stalling. Note the similarity of the spray, with other photos. Bottom Pic: The stall launches Mason.
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These wipe outs may have been deadly. The featured surfers are the best at what they do. Perhaps the end result may not be different with any other surfboard design, as conditions were very extreme and hazardous.
The next trailer features, Tyler Larronde at Jaws. His board sticks midway down the wave and disrupts his balance. He almost regains control, but the board sticks again. He loses control, the board stops, he is catapulted.
vid 5 from youtube
A shorter board is also vulnerable. The board does not need length to stop. Tow boards meet the same fate. Niccolo Porcella falls into a trough at the wave's bottom and gets stuck. Water moving rapidly up the wave face, pushes against the board's bottom. This is evident from spray shooting from under his board, see red arrow. A wake is created and blocks the board. The bottom is likely too flat. Teahupoo clip from WSL greatest wipe outs and youtube.
Rapid Streaming Water
History links our past to the present. It helps us to recognize events which advanced our lives, civilization and technology. Surfing has deep roots in Hawaiian culture. In exploring this past, we can find how those before us advanced. Our past is a compass to the future.
Many surfers today, do not know what surfboards of the past look like. Fewer have ridden one of these surfboards. The boards were big, heavy, and very difficult to maneuver. Shapes were not as refined as today. In spite of this, these old shapes can outperform today's shapes, in chop. A very good design recurring on most boards of the past was abandoned and lost over the years. This design was used by surfboard innovator Bob Simmons possibly as far back as 1945. Simmons designed the modern surfboard. His design was known as the hydrodynamic planing hull. It was popular for many years before being replaced with the faster flat bottom.
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The next clip from You Tube, takes us back on an epic ride with the forgotten surfboard design. Note the bottom hull contours of the boards, as they are carried down the shore.
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Greg Noll successfully rode across several chops without catapulting. The board bounced, however; with his skill, the ride continued. Chops came in a series, causing the board to bounce repeatedly, but; the board kept moving. The last chop launched the board in the air. The surfboard continued moved through chop without stalling.
The next video opens at Waimea Bay with Jose Angel. In the second ride, Greg Noll recovers from a shallow pearl. This is not common today. Note the third ride, the inside surfer's hull catches. It releases and does not launch the surfer. Modern flat surfboards rarely release from high speed water impact.
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The bottoms of the surfboards were rounded. In the old days, the rounded shape was called belly. Belly deflects chop and absorbs impact. Old Polynesian canoes have a rounded bottom, which might have influenced surfboard design. There are no surviving ancient boards to ascertain a Hawaiian origin. Some of the surfboards Duke Kahanamoku rode were predecessors of this shape. Tom Blake was the likely designer. Tom is shown below, at Waikiki in 1929, note the rounded hulls on the left. Blake was a waterman, inventor and surfboard builder. He is also credited for early use of a fin. Duke rides a boat like hulled board in the video from youtube below.
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The boards of the 60s not only rode over chop without stopping, but; were capable of riding out of a shallow pearl. The next trailer again features Greg Noll. His board sticks, then resurfaces, pushing water without stopping. The ride is at the end of this clip from youtube, at the 4:05 minute point. The picture on the left is a frame from Greg's ride. Note how water is deflected by the round bottom. Spray engulfs Noll. This differs from the wake spray generated by a flat bottom which only comes from under the nose. Water is pushed aside by a round bottom. Noll's surfboard continues to move. Water moves out of the board's path, generating a plume of spray. Noll's board skims water on the wave face, where modern flat bottom boards decelerate and stop.
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Skill and determination are factors to Noll's success. He successfully rode out of many dives moving at high speed. Rarely do modern boards recover from a pearl.
Eddie Aikau riding a round bottom surfboard with little rocker, similar to the replica below, survives two nose pokes. Note the large ball of spray that engulfs Eddie. This represents the volume of water that must be displaced out of the board's path, to keep it moving. Flat bottoms generate less spray because they displace less water. Water accumulates in front of a flat bow and causes it to stall in a nose poke. Both riders are behind the peak and bailed seconds later.
Modern surfing dictates innovation. In chop and in steep clean conditions, speeding boards stop when the bow impacts water at the proper angle. The longer the surfer remains riding, the further he can progress. In order to do this, the surfboard must be able to move through water as well as on top of its surface. A surfer can recover from a shallow dive if the surfboard does not abruptly stop. He stops because water cannot be displaced fast enough from under the flat bow of the nose rocker.
Blending designs of the past, with the present can produce a design for the future. Using Physics, we can overcome forces impeding performance. Understanding physics, we can apply Marine Technology to improve surfboard design.
There has been little variation from the traditional flat bottom surfboard design. The flat bottom is very popular today. Surfers are using this design in waves of all sizes and in all conditions perfect or adverse. The flat bottom is used in large waves with rough or choppy conditions. Surfers are also using this board in extreme conditions. They are riding steeper, deeper and in the air on waves possessing inherent deadly consequences. Thus surfers enter a new extreme environment on the same flat bottom shape. Today's new maneuvers and exploration of extreme and large waves require new designs.
The landscape has changed, surfboard design can change to improve performance. Today, surfers are often airborne, in both small and large waves. Hard landings add a new dimension of danger, which may be improved with innovation. Boating designs are scientifically engineered. Surfing designs tend to be artistic. Art, by nature, can be surreal. The perception that flat bottom is the best aesthetic and functional design for all conditions, may not be true. The flat bottom is a good design, however; evolution has changed the playing field. The flat bottom may not work very well in this new environment.
The flat bottom rides on the surface and needs smooth water to perform efficiently. Chop slows all surfboards, but; chop can stop a speeding flat bottom board. At slower speeds, the flat bottom performs well. The flat bottom adds stability and reduces tipping at slower speeds. A product of the single fin era, the flat bottom was usually ridden on the surfboard's forward half toward the nose. With surfer's weight forward, the nose underside or bow effectively pushed water out of the rider's path. The board displaced water so it could move. Single fin boards were narrower in the tail and wider forward of center. This allowed forward trimming with low to moderate nose rocker. Modern vertical surfing has taken the flat bottom to its limits. The wide point is aft of center or at the center. The board is ridden on its aft half with the nose usually above water in the air. High-performance surfing excels when the nose does not poke the wave. Nose rocker was increased to keep the tip out of water. An off the lip is often accomplished by breaking fins free and falling to the bottom. Takeoffs under the lip are done by launching the board into an airdrop. Surfer are landing these, but; sometimes they lose control and poke the nose. The impact is usually on its bow and results in a surfer catapulting. High nose rocker combined with a flat underside or bow can disrupt performance. In competition, this may inhibit advancing.
Evolution and Modern Surfing
Riding on the crest of a wave, a quintessential surfer glides on water propelled by nature's energy. He smoothly slips into a steep surging swell as it transforms into a cavernous vortex. Effortlessly he turns across its emerald glistening surface. His ride is seamless as he maneuvers around and through powerful steep lurching sections without loss of momentum.
Evolution changed surfing forever, gone are seamless flowing rides. A quintessential or traditional surfer differs from a modern surfer. A modern surfer flies through the air, sometimes high above the wave. He flies down the wave and lands tail first, following with a turn after recovery. Flight adds hard flat landings which may require recovery or regenerating momentum at the cost of fluidity. Loss of momentum usually ends his ride. If a surfboard can keep moving after a hard impact with the wave, the surfer may recover. This is achievable with an alternative bow shape. A shape that moves water out of his path instead of blocking his path. Both the modern surfer and traditional surfer can benefit from this alternative.
Evolution has also brought surfboards to its performance limits. Surfboards can be compared to boats crossing through rough seas. Both vessels ebb and flow through an unpredictable ocean, rising and falling at the whim of the sea. Boats climb and churn up large swells. Once over the top, they launch skyward into the air, landing hard on their bows, creating large wakes. The landing robs forward momentum and pitches cargo and passenger. A boat can add power to regain momentum and face the next swell. A surfer cannot add power and is left with no momentum, in a hard collision with water. It is the sudden loss of momentum, in hard flat landings that impedes surfboard performance. Reducing the loss of momentum will allow a modern surfer to progress further and perhaps complete his ride. This may be achieved by using round or V-bows similar to boats.
A planning boat optimally rides on its aft half like a surfboard. Planning hulls differ from hulls of ships and sailboats. They can gain enough speed to rise to the surface hydrodynamically and eliminate the forward push of water. At lower speeds, the front half enters the water. When the forward half is in the water, it clears a path, pushing water aside. Speed is restricted while the bow is in the water, but; the Vee bow shape sustains momentum. Note in the video how the bow parts water and cushions impact. The Vee bow cuts through water and conserves energy, sustaining momentum.
Flat bottom surfaces are designed to create lift, sometimes hydrodynamic lift is not desirable, especially in rough seas. Most surfboards are flat from nose to tail. Flat bottoms do not penetrate the surface deeply. They resist penetration and rise to the top with speed. Water cannot move out from under a speeding flat bottom boat instantly. Water resists movement and supports the boat on the surface. The lift is not with buoyancy, but; with upward pressure created by speed. The water's surface becomes somewhat impermeable and stationary, with speed. Water pushes against a speeding flat hull generating lift. Lift becomes forward resistance pushing against the flat bow of the boat. To reduce forward resistance boat bows are pointed and Vee or round shaped. Note in the hull pictured above, Vee becomes less pronounced toward the rear. Less lift is generated near the bow and more at the stern. A more subtle design works with surfboards. The above hull planes at high speed and displaces water with hard impact and low speed. A displacement bow moves faster through water (in water) than a flat bow. The flat bow is faster when it rides on the surface, but; not below the waterline. Flat bottoms can stop with a hard impact with the water. A semi-displacement hull may provide a solution for surfboards. Semi-displacement boards can ride on the water at high speed and through the water at low speed. They can push water aside with hard impact and maintain momentum.
Flat bottom boat bows will ride in the water at low speed. The hull can move water at low speed. Unlike a Vee bow it does not part water immediately, it first pushes water forward in its path. The process consumes energy and robs momentum. This is called wave-making resistance. The boat creates a bow wave as it pushes water. Flat bows are designed for flat smooth water. These hulls are pushed backward in heavy seas. This rule applies to surfboards. Push back in surfing, occurs in a nose pokes or a pearl dive. In a pearl dive, resistance is produced by water pushing against a speeding flat surfboard underside nose bend. Pressure on top is generated by the surfer's weight. Water pressure on the bottom produces most of the resistance that allows a surfboard to plane on the surface. The same pressure applied to the bent underside produces a reverse force which launches a rider.
Continued in Analysis/Research/Solution