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ghost4man said..Tang said..
Good points Ozzie, but I wonder about the analogy insofar as snow doesn't have curves like wave faces, and skis etc don't have fins to deliver acceleration through turns. Skiers etc are pretty much using gravity as their energy source, whereas surfing uses moving water in the wave, water moving through fins and along the board, and gravity for drive. I agree there are parallels (pun intended) but profoundly different mediums I would have thought.
Cheers
Tang, you are very loosely getting into the realm of Potential and Kinetic Energy in the example of the snow skier. You are correct in saying that gravity plays a part in this which initiates the forward momentum. There are many other factors in play during this movement which include the fact that snow acts as a friction or resistance to this forward movement against the ski blades. So yes they are different mediums and the examples that I used dont include fins. I am not sure about the wording that you use in terms of delivering acceleration through turns. I think that there is a much stronger argument that we have fins to provide directional stability which is critical during the turning phase and a consequence of this is maintaining the already existent speed. Thats probably a trivial point. But what I do think is of value is the fact that in the case of the water skier, we havent as yet, unless I am mistaken seen any blade designs which incorporate a pointy nose which we find in surfing. You have to wonder why. You have to wonder why you have two sports, namely water skiing and snow boarding, with both very different mediums, using parallel constructions, where speed, turning, stability are crucial elements and yet they both retain similar design principles. I am not suggesting that parallel rails should be the standard for sup design but its obvious you can achieve a lot by shortening a sup board significantly, making it narrower and yet increase performance elements like stability and speed.
Cheers Ozzie
No worries, Ozzie. You've got me on the energy issues and physics, but it would be good to hear from you blokes with a background in the theory of planing and hydrodynamics etc about this.
Regarding acceleration through turns - I agree about the directional role of fins and retaining speed, but there is no doubt in my mind that good surfers are able to generate additional speed from multi-finned boards. I don't have the experience on quads, but from watching the pros you can see how they generate speed independent of the wave through turns (watch curren's bottom turn to get around the long section on his 10 pointer at Jeffrey's as a classic example). Back in the day before my back clapped out even I could generate considerable extra speed through bottom turns and cutties, so it isn't that hard to do, though I find it a damn sight harder on a sup! But it is not really trivial, as it is a core component of good performance surfing.
Regarding the two sports with parallel rails, my first observation is that both occur in relatively static mediums and in the absence of wave-like curves. My second is that water skis have a slight elliptical shape with a drawn out tail, while snowboards seem to have a slight hourglass shape being narrower in the centre than either end.
what you say sounds right for speed, but to me surfing brings an extra set of variables for the craft to deal with to be effective. But again, I'm just an outspoken layman on this one!
highvolume
> 9 months ago, 18 Jul 2013
