Hey all, I was surfing yesterday and staring at the little droplets of water riding on top of the surface of water. Like a water-striding spider, the droplets were so light that they were unable to break the surface tension of the very water they were sitting on. These droplets skimmed and moved around on the surface with absolutely no resistance – skittering all about with the slightest breeze. This got me thinking. Would it be possible to build a board surface that utilizes these same prinicples? In effect a board that has no surface tension and skims across the surface like a waterspider? My first thought was to create a board surface that rides on hundreds of thousands of little water droplets – like a safe rolling on thousands of ball bearings. Only in the case of the surfboard the droplets stick to the board and the two skim along the surface like the water droplets I observed. This would require a serious thinking of the matrix that actually touches the water. Then I thought about a electrostatic/hydrophobic reaction that would electrochemically repel the water surface from the board – like trying to push two positive magnets together. Finally, what about a hydrophobic agent that could be applied to the board? I did a quick search on the net and found this product: http://www.prodelin.com/files/shc.htm All of this begs the question: can the chemical/physical surface of current boards be modified to make them travel over and though water faster? S http://www.prodelin.com/files/shc.htm
Hey all,>>> I was surfing yesterday and staring at the little droplets of water riding > on top of the surface of water. Like a water-striding spider, the droplets > were so light that they were unable to break the surface tension of the > very water they were sitting on. These droplets skimmed and moved around > on the surface with absolutely no resistance – skittering all about with > the slightest breeze.>>> This got me thinking. Would it be possible to build a board surface that > utilizes these same prinicples? In effect a board that has no surface > tension and skims across the surface like a waterspider?>>> My first thought was to create a board surface that rides on hundreds of > thousands of little water droplets – like a safe rolling on thousands of > ball bearings. Only in the case of the surfboard the droplets stick to the > board and the two skim along the surface like the water droplets I > observed. This would require a serious thinking of the matrix that > actually touches the water.>>> Then I thought about a electrostatic/hydrophobic reaction that would > electrochemically repel the water surface from the board – like trying to > push two positive magnets together.>>> Finally, what about a hydrophobic agent that could be applied to the > board? I did a quick search on the net and found this product:>>> http://www.prodelin.com/files/shc.htm>>> All of this begs the question: can the chemical/physical surface of > current boards be modified to make them travel over and though water > faster?>>> S Ask Tom Morey… He knows all about this sort of thing. He wrote a big article a long time ago re: concaves, air slots, etc. I have no idea what year - a LONG time ago. How about gluing Alka Seltzer tablets in little recesses all over the bottom of your board? Herbie Fletcher et al. have experimented with a slot concave/fiberglass flap/air hole thing,again, a LONG time ago.
I too have seen those water droplets on top of the water surface and always wondered what the deal was. I don’t know much about science but I remember an old article where the shaper (can’t remember who) who had the idea of a dimpled bottom, sort of like a golf ball with a multitude of little concave dimples and he claimed the board felt like it was rolling along on a million little ball bearings. Sounds like it would be fun to try (although a pain to glass!) Maybe you could dimple the blank with some light touches of a ballpeen hammer!
Hey all,>>> I was surfing yesterday and staring at the little droplets of water riding > on top of the surface of water. Like a water-striding spider, the droplets > were so light that they were unable to break the surface tension of the > very water they were sitting on. These droplets skimmed and moved around > on the surface with absolutely no resistance – skittering all about with > the slightest breeze.>>> This got me thinking. Would it be possible to build a board surface that > utilizes these same prinicples? In effect a board that has no surface > tension and skims across the surface like a waterspider?>>> My first thought was to create a board surface that rides on hundreds of > thousands of little water droplets – like a safe rolling on thousands of > ball bearings. Only in the case of the surfboard the droplets stick to the > board and the two skim along the surface like the water droplets I > observed. This would require a serious thinking of the matrix that > actually touches the water.>>> Then I thought about a electrostatic/hydrophobic reaction that would > electrochemically repel the water surface from the board – like trying to > push two positive magnets together.>>> Finally, what about a hydrophobic agent that could be applied to the > board? I did a quick search on the net and found this product:>>> http://www.prodelin.com/files/shc.htm>>> All of this begs the question: can the chemical/physical surface of > current boards be modified to make them travel over and though water > faster?>>> S There is a pic of an air lubricated bottom in the Vintage Surf Auction in the Classifieds. Shaped by Vinny Ryan some 30 yrs ago.
This whole “skimming-hydrofoiling” concept is interesting. I still don’t know which is faster, a gloss or sanded finish. Perhaps they’re both the same, as long as the finish doesn’t absorb water. Dimples on the bottom of the board for speed? What about if the dimples were small but slightly elongated, like hundreds of spoons. Maybe someone will come up with a new space age coating (not Pam), to coat the bottom of a board. Teflon? Aluminum? Slugslime?>>> Hey all,>>> I was surfing yesterday and staring at the little droplets of water riding > on top of the surface of water. Like a water-striding spider, the droplets > were so light that they were unable to break the surface tension of the > very water they were sitting on. These droplets skimmed and moved around > on the surface with absolutely no resistance – skittering all about with > the slightest breeze.>>> This got me thinking. Would it be possible to build a board surface that > utilizes these same prinicples? In effect a board that has no surface > tension and skims across the surface like a waterspider?>>> My first thought was to create a board surface that rides on hundreds of > thousands of little water droplets – like a safe rolling on thousands of > ball bearings. Only in the case of the surfboard the droplets stick to the > board and the two skim along the surface like the water droplets I > observed. This would require a serious thinking of the matrix that > actually touches the water.>>> Then I thought about a electrostatic/hydrophobic reaction that would > electrochemically repel the water surface from the board – like trying to > push two positive magnets together.>>> Finally, what about a hydrophobic agent that could be applied to the > board? I did a quick search on the net and found this product:>>> http://www.prodelin.com/files/shc.htm>>> All of this begs the question: can the chemical/physical surface of > current boards be modified to make them travel over and though water > faster?>>> S
Surfco Hawaii makes a product called “Ultra Glide Speed Coat.” According to their ad the stuff, “Creates a water repellent coating that enhances board performance and cleans the boards surface.” I’ve never tried it personally but I have my doubts. Morey Bodyboards used to make a board called the Mach 8TX. The textured bottom of the board has hundreds of tiny dimples (ala golf ball). The dimples trap a bubble of air under the board, reducing water friction. When you get up to a certain speed the board releases and has a free, floaty feel. It might be difficult to re-create this type of bottom on a standard fiberglass/resin surfboard. I’ve seen a lot of phazers, dips, steps and other speed enhancing doo-dads in the 80’s but they kind of died out. Check out Y’s (Tom Morey’s) Triplane air-lubricated board on his Swizzle website. Sounds scary!
Although I don’t that is repels water, spray coatings were thought to have this quality of gliding. Remember when gloss went out the window and spray coatings were used to seal a board, they had some texture to them and guys swore they went faster. Perhaps this coating or a teflon coating would make it glide even faster. Thanks for the link and idea.
Although I have never seen the phenomenon you experienced, I suspect it has more to do with the salinity (salt content) of the seawater vs. what I am assuming was fresh water rain mist. (Just about everything floats better in the sea vs. fresh water because of the salt content) Regarding the crux of your inquiry, I think what you seek is a way to build a faster board by modifying the surface area in some way. I think it is relevant to consider how racing boat builders view this problem. They have a basic formula for determining the boats resistance in the water. The three basic variables are: hull displacement and wetted surface area and skin drag. Therefore, racing sailboats are as light as possible and have narrow hulls (thus reducing their displacement and wetted surface area). With regard to Skin drag there was an attempt in the late 80s by 3M to produce a Shark skin like product, which could be laminated to the bottom of boats to make them slip through the water faster thus reducing skin drag. This same technology is currently being experimented with in racing swimsuits. However, the fundamental problem is that a sharks rippled skin has evolved over millions of years to aid a shark move faster through the water at its highest speed. This speed is much faster than a boat, swimmer or a surf board ever travels. (unless strapped to a car) Likewise could be said of a golf ball design. I think this is why 3M no longer makes Shark Skin, swimmers dont go faster wearing these special suits, and golf ball dimples dont work on surfboards. So, before everyone start hitting their boards with ball hammers as was suggested in one post, I would suggest it would be more worthwhile to consider the first two variables in the formula: hull displacement, and wetted surface area. Regarding these, one could consider using more buoyant material (perhaps styro-foam) and/or produce a lighter skinnier board. However, this is at the risk of ignoring the obvious solution. Which is&…your not going to like this&. Lose weight! If you really want to move faster through the water drop any unnecessary pounds you may be carrying. This alone would have a far more dramatic affect on speed than anything you could do in your workshop. Greg Lemond (3 time Tour de France winner) once said that he estimated he lost 5 min. (in the mountains) for every ½ pound of weight he was over his ideal. This same type of thinking can be compressed down to those times when you are trying to generate wave catching speed and/or trying to move faster on any part of the wave. Less hamburgers = More speed
i like your analogy about greg lemond and lightweight climbers. on the other hand, the flyweights of professional cycling, who are the best climbers, have to descend also. before their descents they make sure to get full waterbottles, stuff their jersey pockets, and do whatever the rules will allow to gain weight for the way down. i guess it depends on what you want to do. if laird hamilton went down to 135 lbs. he might get hung up on the faces, and get broken in half. you make a good point though!
With regard to Skin drag there was an attempt in the > late 80s by 3M to produce a Shark skin like product, > which could be laminated to the bottom of boats to make them slip through > the water faster thus reducing skin drag. This same technology is > currently being experimented with in racing swimsuits. However, the > fundamental problem is that a sharks rippled skin has evolved > over millions of years to aid a shark move faster through the water at > its highest speed. This speed is much faster than a boat, > swimmer or a surf board ever travels. (unless strapped to a car) Likewise > could be said of a golf ball design. Thomas, Thanks for the info – but I think not being able to catch up with one million years of shark evolution is not what’s going on. Sharks have been evolving millions of years longer than we have and they haven’t invented a transistor radio. More than likely 3M saw no profit in the project or the theory just isn’t fit… I looked for links to “shark skin” and lo and behold I found the speedo site. Here’s what they say: “FAST.SKIN fabric is based on a shark’s skin. The shark, like a swimmer, is not hydrodynamic but is extremely fast in water. Why? It has a skin that minimises drag and maximises efficiency. The secret: dermal denticles. FAST.SKIN fabric mimics these v-shaped ridges, creating small vortices. FAST.SKIN has a denticle-shaped resin print on the fabric. This creates large vortices. These two currents ensure the water is sucked closer to the body – this reduces friction drag. The body slips through water more smoothly.” Would anybody like this surface on their board? (even though it would suck without a wetsuit…>;-)
i like your analogy about greg lemond and lightweight climbers. on the > other hand, the flyweights of professional cycling, who are the best > climbers, have to descend also. before their descents they make sure to > get full waterbottles, stuff their jersey pockets, and do whatever the > rules will allow to gain weight for the way down. i guess it depends on > what you want to do. if laird hamilton went down to 135 lbs. he might get > hung up on the faces, and get broken in half. you make a good point > though! The point is of course the less water displaced will equal faster speed. Speaking if Laird Hamilton, have you seen his Air board? I think this is the ultimate expression of this concept. For those that dont know he (laird) built a 4ft surfboard with a hydro foil attached to the bottom. He and the board actually ride down the face of the wave completely out of the water. Relying only on a wing shaped hydro foil to keep him in contact with the wave. This enables him to ride much bigger, bumpier, faster waves because his crafts hull displacement is almost zip. As far a weight adding to Laird Hamiltons speed or speed in general; remember the that it is a fundamental property of physics that weight has nothing to do with an objects gravitational pull by the earth or the speed of which said object falls. (Its the old drop a bowling ball and a marble at the same time experiment) If anything, weight only contributes to speed via its ability to overcome wind resistance by creating a greater force of inertia. To further explain why golf ball dimples dont work on surf boards, my engineer friend adds: Another reason why dimples don’t work on a surf board is because most of the drag is skin drag. Dimples on a golf ball help to trip turbulent airflow. Turbulent flow is more apt to change direction and will conform more to the ball’s shape than laminar flow. Turbulent flow will adhere to the trailing edge of the ball longer thus reducing the low-pressure zone trailing the ball. The smaller the lower pressure zone the less pressure drag. I think a more interesting and perhaps fruitful discussion might be made of the post, which suggested that something hydrophobic (water repelling) be coated to the bottom of the board. (Teflon spray or snail slime?) This might serve to reduce the surface tension of the board with the water. However, it also might make the board useless in holding a rail. Additionally, I suspect this idea has been tried and discarded by the swimming community long ago either because it didnt work or because it felt too creepy.
Thanks for the info – but I think not being able to catch up with one > million years of shark evolution is not what’s going on. Sharks have been > evolving millions of years longer than we have and they haven’t invented a > transistor radio. More than likely 3M saw no profit in the project or the > theory just isn’t fit…>>> I looked for links to “shark skin” and lo and behold I found the > speedo site. Here’s what they say: Dont believe the hype& Not to play to for tat&but, this site explains why the stuff doesnt work for swimmers: http://www-rohan.sdsu.edu/dept/coachsci/swimming/bodysuit/knowsuit.htm You are probably right about 3M not finding this product commercially viable. However, dont you think if it worked every sailboat racer and wanabe in the world would want the stuff? Would it then not be commercially viable? Yes, it is true in 1987 Dennis Connor won the Americas Cup back with a boat laminated with 3Ms product. But if it were the secret to his success, dont you think he would have continued to use it on subsequent boats? Its a nice idea (one that too I considered many months ago) but, now I think I will stick to my less hamburgers = more speed (less hull displacement) theory. I think it has the greatest chance of helping me reach the goal of faster board speed.
Hmm…suppose you study the flow properties of a single element in the “shark skin” pictured here. Take that thought and transfer it to the bottom contours of the aforementioned “finless” craft. (Mike, did you get a weird e-mail with a link to an old Tom Morey lake/towboard I forwarded from an e-bay auction? Similar lines on the bottom of that craft.) Tom Sterne>>> Thomas,>>> Thanks for the info – but I think not being able to catch up with one > million years of shark evolution is not what’s going on. Sharks have been > evolving millions of years longer than we have and they haven’t invented a > transistor radio. More than likely 3M saw no profit in the project or the > theory just isn’t fit…>>> I looked for links to “shark skin” and lo and behold I found the > speedo site. Here’s what they say:>>> “FAST.SKIN fabric is based on a shark’s skin.>>> The shark, like a swimmer, is not hydrodynamic but is extremely fast in > water.>>> Why?>>> It has a skin that minimises drag and maximises efficiency.>>> The secret: dermal denticles.>>> FAST.SKIN fabric mimics these v-shaped ridges, creating small vortices.>>> FAST.SKIN has a denticle-shaped resin print on the fabric.>>> This creates large vortices.>>> These two currents ensure the water is sucked closer to the body this > reduces friction drag.>>> The body slips through water more smoothly.”>>> Would anybody like this surface on their board? (even though it would suck > without a wetsuit…>;-)
Anyone notice th resemblance to a try fin set up here in the pick of the speedo/shark replication? Pretty interesting…
I say try the hydrophobic spray, keep it away from the rails, and see what happens. It’s cheaper, as an experiment, than the other options (except starving yourself). A micro-thin layer of air between the board and the water makes sense to me. Attempting the shark skin principle could take you on a long, round-trip to nowhere, mainly because you’d have to find the proper medium on which to place the pattern (I don’t think spandex would fit too well on my board), unless you could screen the pattern directly onto the glass (could work?). As for designing fins to mimick the pattern, you have to think about all the proportions involved in the shark’s skin and shape. The same size/shape “denticles” may not work on forms other than sharks. Each creation is created with its own special attributes for a specific reason. Example: Gluing feathers to human arms was abondoned for good reason. At any rate, why do we want more speed? For more information, have another listen to Simon and Garfunkel’s “Feelin’ Groovy.”
I think it was the Willis Brothers on the north shore who were doing the dimpled bottomed thing…i’m wondering about reducing fin drag/turbulence from the same ideas. i heard about airplane designers producing more efficient aerodynamic wings by putting a texture on the leading edge, like a sandpaper grit, the idea being to disturb, or i think they said “excite”, the air molecules flowing around the wings, producing significantly less turbulence. i’m not a physicist but i wonder if this would have a similiar effect on fins in water? or bottoms for that matter…