Succinct and measurable.
So for the energy involved; it is gravity, velocity, wave height and mass (surfer + board).
I like it…
Below is Savistsky’s rotated diagram of the forces of planing (see origin post above). In it I’ve indicated the two vectors which are relevant here; ‘force due to planing’, and ‘force due to gravity’.
The force due to gravity will counter-balance the oppositely directed force resulting from planing -i.e. here, the force due to planing has a component in the opposite direction to gravity, which the force due to gravity counter balances.
How the forces due to planing are directed will depend on the orientation of the surfboards wetted-surface, as mentioned in the original post above.
Also as mentioned in the original post, the use of gravity to gain some additional kinetic energy, in a manner similar to a skier sliding down-hill occurs commonly in surfing (see original post above). But as noted, the option (of climbing and dropping) isn’t available when the surfer is in the pocket or getting barreled. In those cases it’s about ‘trim’ - maintaining a velocity with a transverse component (see original post above).
I’m not gonna read or address the technical stuff here - over my head, and not the way my mind works anyway. But its obvious to me, if you’re thinking of gravity as a force moving the surfer, like a downhill skiier, you have to factor in the fact that the “mountain” the skiier is descending is also moving. Then factor in that the top of the mountain is pitching forward, and in so doing, a curl is created that is moving along diagonally to the forward movement of the mountain. Both of those factors will magnify the effect that gravity alone would produce. A surfer perfectly slotted in the curl, in trim and not descending the wave face, is not propelled by gravity alone. The forward movement of the wave, and lateral (or diagonal) movement of the curl, are key factors.
Huck,
The Brainiacs are overlooking, or ignorant of the fact that a well foiled fin is a significant part of what propels a surfboard across a wave. I’ve stated before, that we are flying our fin, when riding a wave. The fin is doing the same thing the sail on a sailboat is doing, when sailing into the wind. The board is being powered by the ‘‘flow’’ of water moving up the face of the wave.
Inside the barrel, outside the barrel, the slope is still moving continously.
Traveling parallel to the water’s/earth’s surface, speed will keep dropping because of drag. There must be some angle of descent for the board to move along the face (forward).
I could be wrong. But I do not believe anybody rides parallel to the surface for any significant period of time.
EDIT: I understand that science/physics is not your thing. But for reference:
http://faculty.wwu.edu/vawter/PhysicsNet/Topics/Dynamics/InclinePlanePhys.html
**Component of gravity pushing the block down the incline plane.
Wx’** = mg sin(q)
**Component of gravity pushing the block against the incline plane.
Wy’** = mg cos(q)
If you’re so inclined, please read my post “The Decelerating Wave-Form”.
As for the ‘lateral (or diagonal) movement of the curl’, again I would refer you to “The Decelerating Wave-Form”.
Though a digression, but nevertheless an important matter to keep in mind, the transverse motion of the curl is basically governed by bottom topology (see following argument). A simple way to appreciate this is by considering two relatively opposite cases; a wave that closes out, and a wave that ‘peels’, and realizing that there is an infinite number of cases inbetween the two. How fast a wave ‘peels’ is a function of the rate of change of bottom topology, and can be ‘uncoupled’ or is independent of the celerity of the wave-form, in as much as one could always adjust the bottom topology to match a given “peeling” rate. Or to put it another way, even the seemingly slowest shoaling wave-forms can close out.
Fins are not critical to surfing, whereas your statement “The board is being powered by the “flow” of water up the face of the wave”, is very much a part of surfing (see original post above.)
The net force due to planing has two components, vertical and horizontal (unless turning), these components will be lift and drag the force won’t act perpendicular to the surface as shown. Your diagram would give an ever accelerating board.
I’m not following your argument at all. Perhaps you could provide some greater explanation.
The Savitsky diagram as originally drawn has the planing force with lift and drag components. You have these as lift and propulsion, what has happened to drag?
The question is , what makes a surfboard go , the answer is , the surfer . How the surfer makes the surfboard go is a different question and its not just science , physics , algorithums and fucking quadratic equations , the surfer does not pull his slide rule or pocket calculater out of his arse when he paddles out to analyze the approaching wave , when he drops in he uses something else , something we have all got but many of us dont use nearly enough . Think about it , dont get over intimidated by the scientists who go on and on and on and on and on and on and are sooooo fuuucckking booorrring because they think their way is the only way . You all know the answer , speak up , come on spit it out , cant quite grasp it , a clue , its in the title of another thread that the scientists dumped on . Without it most likely none of us would be here . Much Aloha . T .
Where in Savistsky’s diagrams is anything labeled lift or drag? Admittedly, I’ve used the term drag (see original post), along with a brief explanation as to how it is used.
Though I think I might see how you’re misinterpreting the diagrams, I’m not about to start telling anyone what’s in their head. So at this point, rather than just repeating what I written, if you’re inclined, perhaps you might provide further explanation. (I don’t expect anyone to make a diagram, but in this case, if you are able to, it would be helpful.)
Though it might not be related to your comments, any 3-dimensional force, like that of planing, can be resolved in a 2-dimensional manner using perpendicular components like those of Engineering’s lift and drag. But to do so you first have to set the direction of one of the components. Again, this might not be related to your comments, and if not forgive the digression.
You and I both know, that is not the only force powering the surfboard’s movement on the wave. But to say that ‘‘Fins are not critical to surfing…’’ is foolish at the very least. I suppose it depends on how you want to define surfing. Top to bottom surfing, in larger,waves, and instantly, reversing direction at will, are all maneuvers that REQUIRE a fin. And don’t hang your arguement on the finless Hot Curl boards. Once a Hot Curl board reaches the bottom of the wave, you cannot climb back to the top of the wave. This observation from Buzzy Trent, who rode those boards ‘‘back in the day.’’ Fins ARE critical to the way most people surf. Me among them.
Fins, like so many other desing components have definately enhanced surfing (for example, they have allowed surfers to push the limits of what can be surfed with some degree of control, and more), but I stand by my comment, they are not critical. Please see Bill “Beaker” Bryan doing his thing.
if this were the answer, then the surfer would be able to surf on open flat (waveless) water on a perfectly windless day
Good one.
LMAO
First thing that makes a surfboard go is the phisical propultion of the surfer paddeling. Then I would have to say that it is gravity and inertia that makes a surfboard go on the wave. What a dumb question. Ha,ha
Have you ever seen a no-paddle takeoff? Paddling, while common and helpful at takeoff, is not essential to surfing.
IMO, its not a dumb question. To my mind, it should be fundamental for people who design and build and study surfboards to analyze what makes a surfboard go. That there can be so much disagreement is really astounding, and shows me that it is a question we should all think about more, not less.
This makes sense, to an extent. The sail on a boat catches the wind, and by being angled to the wind, creates lift diagonal to the direction of the wind. The opposing force created by the water against the keel pushes the boat forward, into the wind (not directly into the wind, but at an angle), not unlike two opposing forces propelling a watermelon seed forward when we squeeze it between our fingers. The forward direction becomes the path of least resistance. But for the the upward movement of the wave face water to do the same to a fin as the wind does to a sail, you have to explain where the opposing force is coming from - is it gravity?
Maybe I should just drop out of this conversation, and let the technical jargonistas take over, since we aren’t communicating anyway. I don’t read their posts, because I don’t get anything from them. But to my mind, the wave is the biggest factor in making a surfboard go. Gravity, moving water, and the kinetics of the surfer play into it also, but the wave itself is the key factor. The wave energy is the energy we tap into when we surf, not our own energy or the downhill power of gravity alone. If you look at what Laird and Brett and WoodDave are doing with foils, tapping into the wave energy below the surface, you have to recognize the power of the wave itself as a driving force. Look at how much more power there is in a bigger wave than a smaller one. Is this because it has more gravity? Of course not. If a skiier walks 10 feet up a slope and slides down, then walks 20 feet up the same slope, does he feel more power? No. But a 5 foot wave compared to a 10 foot wave - wow. That’s not just gravity.
I took a look, as you suggested. Someone doing skateboard tricks, on ankle snapper waves, is not the kind of surfing I described. Nor does it support your statement. If you don’t think fins are critical to surfing, then you’ve never surfed a wave of significance, that would deal out punishment if you F’k’d Up, or had crappy equipment. Seems to me, you are long on theory, and short on experience.