You know, I’ve been trying not to get involved in this converstion because it makes me feel like I took my stupid pills this morning.
But I just can’t reconcile one particular thing with the idea of UP - flow.
If there is significant flow upwards, how is a duckdive possible?
Ok, maybe at 3’ Trestles, you can create enough force from your paddling speed to penetrate to the back half of the wave and bypass the upward flow. Maybe, maybe, its possible at 6’ Blacks. But 10’ Ocean Beach? 20’ Waimea? 30’ Mavericks?
a 30’ wave at 20 seconds is thicker than it is tall. I just don’t think that with paddle power alone, its possible to drive yourself (& the bouyancy of a 10’6" gun) halfway through the wave to reach the presumed downward flow on the back. In fact, I would think that since a volume of water equal to the volume of a surfer + board would be denser than said surfer & board, that volume of water would nearly always win the flow vs. penetration contest. Given this, if there were actual upward flow of molecules, no duckdive would be possible, anywhere.
Skip the fancy science & physics for a moment, Kevin, and just explain the duckdive to me if you could. Because if you’re right, I don’t see how the duckdive is possible at all. You’d just get “flowed” up to the lip and either go over the back or get chucked down the front.
Well, has anyone gotten anything out of all this that you weren’t getting before?
Like, did your surfboards seem to be working according to a working understanding without this flow factor? Does the flow now seem to be a vector factor you were perceiving on the periphery of your dim little surfer consciousness, but just couldn’t quite pinpoint, and now everything makes sense and you wonder at how all surfers everywhere have been so dull as never to have picked up on this thing?
Has there been a suggestion here of anything that enhances your understanding of any your previous experiences of riding waves, sitting waves, paddling out through them, diving under them, paddling for them, or anything that could really enhance your future experiences of them in any way?
I think the flow as presented by KC is a synthetic red herring. Made of tar.
This thread series has been like absolutely nothing else in my recent life as much as this conversation about religion I had with a straightup willing-to-fight-for-a-Catholic-theocracy ideofascist I ran across last night, circular arguments and all…
While I do not speak for others, I do not find Kevin rude. His responses have be short and to the point in some cases. Perhaps frustration on his part. It is difficult to respond to some of the people criticizing him because they don’t understand basic physics or math.
I think it is great that someone has taken the time to think about surfing, waves, and board design theory from a scientific/engineering point of view. If that’s not your thing, fine. Pass on the discussion. If you want to question his theories or analysis, that is fine too. But if you don’t use the language he has framed his argument with (physics) then you won’t be able to communicate. Frustration on all sides will result.
Until the last few posts I was quite happy to listen to what he had to say. But the last few have been belligerant, IMO.
As for “what have I gotten out of this”. A little. I agree somewhat with the upflow thing and think it’s an interesting area of investigation. I also think it’s an interesting part of the mechanics of a wave.
I certainly do not appreciate his recent responses to me, since I am giving him a fair go and willing to discuss things with him.
You see, I think Kevin is right about the wave motion. It explains how a wave sucks water out from in front of it, for one thing. I reckon the upflow is really there. I have stated that I don’t believe that it is the major source of power in surfing, although it can be harnessed to some extent. I have stated that I believe potential energy is responsible for most of the way we surf, followed by wave forward motion. Kevin is refusing to discuss that. If Kevin wants to ignore potential energy and forward motion - pretend it does not exist - I can’t stop him… And I don’t really want to.
I just thought this was an honest discussion. Without that all we are left with is arguing… And you know what they say about that.
It’s microthink. It’s a red herring. It’s a chimera. It’s a tar baby. It’s the answer to a question nobody was asking. It’s an attempt to assert something is the whole of surfing when no other surfer seems to have ever noticed it. It’s a billowy cloud of purest gas.
It’s an argument about a factor that’s overwhelmed completely by the acceleration factor of gravity and the forward speed of the wave itself which exceeds the flow speed by a multiple of 2, 3, or 4. It’s an incidental result of the wave itself, not the wave itself.
Hey Doug, nothing personal, but as the father of a child who has competed in the Special Olympics, I find that particular “joke” less than funny… obviously you’ve never been to one or I doubt you would either.
Might I suggest instead “arguing on the Internet is like hitting yourself in the head with a hammer… it’s pointless and it feels so good when you stop.”
Image removed. Shouldn’t have posted it in the first place, please forgive my frustration.
Nope, haven’t been to one BUT my inlaws all either do or have worked extensively with the handicapped. So I have met quite a few. I also have to say that the overwhelming majority of them are simply the nicest people I have met.
If you can PM me a funny image with that text on I’ll put that up in it’s place.
Your level of float is a function of how much of your body is submerged–if the water level rises, you do too–
are you stoned out on them drugs>>??
No I haven’t. . … . I agree with you . . . . however when the water level rises, it flows. . . and does work at the same time. . … just because I used the word ‘flow’ to describe water movement doesn’t mean that I agree with Kevin’s horizontal flow theory.
The main difference between horizontal and vertical flow is that vertical flow is opposed by gravity. . … horizontal flow only by the inertia of the surfboard and rider. … it’s a big difference.
Observe a wave, for example a big wave such as Jaws. Pick something floating in the water. Time it as it floats from the trough to the crest. Compare that to how fast the surfer is going. This example clearly demonstrates how insignificant upward flow is to propulsion.
Incorrect.
Upwards flow is opposed by gravity, and thus the upwards flow does work and imparts energy to the board which is greater than the kinetic energy of the upwards movemenmt. . . it’s called gravitational potential energy. . …
Horizontal flow is opposed only by the inertia of the object and is unable to do further work once the object has accelerated to the same speed as the horizontal flow. . . .thus horizontal flow is the one which cannot drive a surfboard faster than its rate of flow. . . furthermore it is impossible for a surfboard to travel in any other horizontal direction than that of the horizontal flow direction due to that horizontal flow once the inertia of the object is overcome, because there is no opposing force (Kevin is incorrect in stating that this is possible, and I can prove it if you like)
can any of you gravity heads tell me where it comes in to play ( other than the confines of our planet)
if your riding on your gut on a 1/2 foot wave
on a body board
in front of the whitewater
your not up the top of anything! (except water and the body board)
you are at the bloody bottom of the wave out in front!
but your still moving
wtf is going here ?
The discussion so far has not included propulsion via whitewater, which is another case altogether and which cannot be used to support any theory about what makes a board move on the wave face. .
Yes please! Either in PM or public post. You know by now that I’m not interested in the ego thing… And I am not necessarily disagreeing with you. I just love proof! Do it mate, it’s something I enjoy, selfish me
As you know, if there is mass with velocity moving due North, it will not change its direction unless it meets another force. . . . and once the surfboard and rider is moving with the horizontal water flow there is no force meeting the horizontal flow. . . end of story (Note: angling the surfboard will not produce an opposing force once the board is travelling with the flow)
(The horizontal flow is only opposed by another force while there the flow is overcoming the inertia of the object as it accelerates that object to flow speed. . . and that is the only time that the horizontal flow can move the object in a direction other than the flow direction, and the only time during which the horizontal flow can exert force on the object)
Next trick:
According to my calculations:
Example
Moving a 100kg object horizontally from a standing start to 3m/s takes 450 joules (in the absence of friction). . . assume that the object moves 5 metres.
Energy(Joules)=1/2 x Mass(kg) x Velocity(m/s) x Velocity(m/s)
Energy(Joules)=1/2 x 100 x 3 x 3
Energy(Joules)=450
Moving the same object over the same path in the vertical plane takes
(Potential energy at 5 metres height) + (Kinetic energy at 3m/s)
{Force(Newtons) x Distance(Metres)} + {450 Joules}
{ 980 x 5 } +{450 Joules}
4900 Joules + 450 Joules
= 5450 Joules
Therefore in this example the wave does more than 12 times as much work to the 100kg surfboard and rider in the vertical plane than it does in the horizontal plane.
Thus the surfboard and rider have at least 12 times as much energy available via gravitational potential energy due to upwards flow than they have due to horizontal flow… . .
"The only water particles that matter to surfing are on the surface."
I disagree! The rising water particles inside the wave give the wave height, which translates to potential energy. So I assume you are talking about upflow in terms of how it directly interacts with the craft, rather than how it affects the wave.
That’s incorrect. It’s the wave that give the water particles motion, not the other way around. But that’s not what I was referring to anyway. That’s why I ask everyone to be clear that there is a difference between the wave and the water. And my statement about only the water particles on the surface matter to surfing, not the deeper ones, which have less motion (http://www.seafriends.org.nz/oceano/ocean04.gif), was an effort to narrow down some facts that I felt KCasey would agree with since his argument is with the potential of water molecule flow. Of course the wave itself is important. And wave height is important. But water particles do not give a wave it’s height.
Quote:
"I'm referring to water molecules, not the wave. We only surf in water as deep as our fins."
So how does the wave get it’s height? It certainly isn’t as big/steep in the open ocean, even tho the energy is great in open ocean waves. When the wave approaches a break and the H2O molecules start to get pushed up (sucking water away from the front) we get wave height. So the whole wave really does matter. even tho we feel as tho we only interact with the surface 1’ or so.
Yes, if you’ve read any of my previous posts you will see that it’s the wave that’s important, not the water particles. The wave itself is nearly all of it.
Quote:
"It's just gravity."
No! Emphatically. It isn’t. Gravity simply allows us to harness wave energy.
This is too obvious. Of course it’s about using the wave to allow us to use gravity.
Quote:
If gravity and gravity alone was at work you would have a really hard time travelling faster than something like 20km/h. Yet surfers commonly exceed this.
I think here you are talking about surfers exceeding wave speed, not exceeding the speed of gravity. Isn’t terminal velocity over 200 mph. How fast can you go down a hill on your skateboard? This is the sort of gravity I’m talking about.
Quote:
it's about using gravity to tap into the energy band inside the wave.
It’s more about using the wave to tap into the energy of gravity.
Quote:
KCasey, Silly, janklow, kenz... I suggest we start to find points we agree on so that we can approach our differences of opinion from a clearer, more adult perspective.
can any of you gravity heads tell me where it comes in to play ( other than the confines of our planet)
if your riding on your gut on a 1/2 foot wave
on a body board
in front of the whitewater
your not up the top of anything! (except water and the body board)
you are at the bloody bottom of the wave out in front!
but your still moving
wtf is going here ?
Next time you’re at the beach let the whitewater hit you while you stand in front of it. Do it in deeper water so it hits you at about chest level. Take notice of where the force is coming from. Is it from the whitewate, or just below it? It’s below it, because there is still a wave there. The whitewater is mostly air. Although it’s true that the whitewater is the only time in a waves existence that the water molecules actually move forward with any significance.
When a wave breaks, it only loses it’s top. It doesn’t suddenly stop being a wave and lose all of it’s wave energy. It doesn’t lose all of it’s energy until it hits the shore. It’s the gravity from the wave that moves the whitewater towards the shore. You don’t see the steepness of the wave because it is under and behind the whitewate. If you watch whitewater you will see it kind of tumbling. What’s causing this to happen for often times hundreds of feet after the wave has broken?
In deep water, waves can travel at hundreds of miles per hour. I would imagine that the upflow speed is pretty fast compared to the slower waves that we surf on near the shore.
Based on the theory you are supporting, would you say that these deep water waves are surfable?
It simply isn’t a major factor in wave riding 
