Drive Defined?

General Discussion
21

So we agree that tic-tacing works, I think. I mean, try it out on your skateboard. I’m convinced.

What is the relation between “pumping” and “drive”? Could drive be a drawn out tic-tac? I think that drivey turns are the result of selecting a vector in some opposition to the direction of the water. Perhaps that’s the tac.

I think that fins and drive do create speed in a way. The reason I think this is that I’ve ridden boards with small fin surface area. I can get them to go in the direction I want, that’s not the issue. But I still feel like they don’t go as fast as boards with more optimal fin surface area/positioning. So my conclusion is that the increased drag caused by the fins is more than off set by something else, what I call drive. I mean, a finless board isn’t by definition faster, right?

C

22

I’m not in agreement that tic-tacking on a bank or in a ditch works. Try it, using the same angles you would on a wave.

I should clarify–you break your wheels loose at those angles. ON a surfboard, the lift from the hull and fins together is what enables you to pump a face.

I guess that depends on how shallow the angle of the ditch wall is, but the point I’m trying to make is, you’re pushing off the hull’s lift, and the fins’ lift. But the analogy between surfboard and skateboard is sketchy without the hull lift–a snowboard would be a better analogue.

23

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Running summary…

  • ability to make large turns (LeeV)
  • acceleration when the board is weighted (everysurfer)
  • work against the flow … to build speed (everysurfer)
  • projection, acceleration and speed (Wildy)
  • lift (janklow, see additional qualifying comments in his follow-up post )
  • 'road' holding (balsa)
  • capture flow and build speed (nj_surfer)
  • conserve kinetic energy through turns...optimizing capture and direction of flow (nj_surfer)
  • minimizing lateral drift (crafty)
  • force/energy imparted to wave/board/system by rider (obproud)
  • thrust (nj_surfer)
  • marketing-hype, a conspiracy by fin manufacturers (crafty)
  • Page Not Found | Swaylock's Surfboard Design Forum (wouter)
  • speed creation via optimal fin and board surface area and technique (c-slug)
Okay, I'm just being silly with the third and second to last entries... actually, maybe not so much with crafty's comment, or my twisted interpretation of his comment.

… on the engineering terms lift and drag

As there is little about the dynamics of surfing that couldn’t be described in terms of the engineering terms lift and drag, with respect to the use of the term ‘drive’ the question tends to be a matter of what sensation is being referred to. .

… a theme emerges!?

Turning, maintain speed (in a viscous medium), lift, a sense of projection, or even holding or what I suspect may be the same thing, a sense of engagement or connectedness with the wave or flow (at least, I hope I’m interpreting balsa’s comment correctly) all speak to force, and in particular, acceleration.

Though it has been my personal choice to have to avoid using the term, I have to admit, the above tends to be consistent with my guess as to how others have used it. Nevertheless, the variations are there, subtle as they are … at least, subtle enough to frustrate the crap out of me over the years.

… again it’s a sensation, …a perception

We have the physiological tools required to perceive acceleration, or the lack of it, even the smallest of changes: the little nudge you get when you get screw up a bit and get a little to far out in front of a wave; the deceleration when you get to far out on the shoulder; the sensation of ‘weight’ during a turn, pushing off at some point in a maneuver, etc.

… a matter of quality?

Though acceleration is likely key, the term drive appears to be used to refer to the quality of the acceleration. In particular, it’s my guess is that it’s referring to an acceleration which is smooth and uninterrupted, even if it only lasts a small time, at least longer than what you might call jerky or a jerk.

… it’s not just in the design

What is also particularly neat about most of the posts is as to what design element(s) the ‘drive’ is being attributed to, or under what conditions it’s ‘felt.’ If nothing else is clear, technique would seem to be a strong player, design potentiating the sensation of drive for a given surfer or technique. One man’s ‘drivey’ board may be another’s turd … kind of thing.

Nice thread.

kc

24

I think the component that gives you forward motion on a skateboard or a surfboard is essentially the same. That is the resistance of the medium you’re pushing against. In physics the saying is something along the lines of, “for every action there is an equal and opposite reaction.” Without this, you would push on your surfboard or skateboard and no lift, drive, or otherwise would be derived. Call it lift, drive whatever, it’s resistance. Think about grippy wheels vs. hard street wheels, the hard wheels slide out, the soft grippy ones hold. Same with fins, like C-slug mentioned, small fins help hold a line, but they don’t give the propulsion (drive) of properly tuned and sized fins for a given surfboard.

25

Downward…inward…outward… depending on the changing wave face and speed of the wave. Nowhere is this more evident than on the nose, right? I guess we become acutely aware of trim angle when noseriding to the point where adjusting it becomes second nature… automatic… zen-like!

It’s like all of the lift created under the board has a sort of center… kind of like there’s a center of gravity on a person that changes when you move. That center of lift, or focus of force, is always shifting under the board (usually somewhere between your feet on a shortboard), and you balance over it - play with it, like a circus actor, doing tricks while balancing on a giant ball.

26

That’s exactly what I think. I couldn’t have said it better.

27

now just shut up and keep your hands on the wheel…

Stan Ridgway - “Just Drive She Said”

http://www.youtube.com/watch?v=XLXLEghUgo0

28

A finless board will have less drag, and therefore theoretically a higher maximum speed. But in actual surfing you can see that fins help to generate speed through their ‘‘controlled drag’’. Put another way, you can’t hop up on a finless alaia and do a couple of quick pumps to get to speed. But once the alaias have a chance to set a line and hold it for a few seconds, they build a lot of velocity.

I agree this is a great thread. Janklow and crafty and kc and obproud and c-slug and all, back in form. Reminds me of what I read when I first started lurking on here about 3 years ago.

As for a definition of drive, I’d have to paraphrase the old line about pornography; ‘‘I can’t tell you what it is, but I know it when I feel it!’’

29

(Read tongue in cheek sarcasm.) Thanks a lot John… Now I had to open another window, 'cuz I’m stoking up on World Party’s “Ship of fools.”

As for this… As my Hispanic friends, when I lived down south, use to say, “Ai way!”

I agree with most of this, and like many of the threads of this type, there is so much going on while riding it seem hard to attribute it to any one feature of a board, but I would suggest the gestalt of a surf boards functional parts is about lift and release.

As master Ambrose so wisely put it, “It’s all about how the board works in the bottom third of the wave.”

To me, when you’re “down there,” that is often the make or break of many a given ride, and it’s the lift provided by the board and fins which make “making it” possible.

If I happen to say a board of mine is drivey, I’m usually talking about off the bottom on smaller/mushier waves first, down the line “pumping” second.

Aren’t Balsa’s Euro $.02 worth a couple US bucks these days? Ha!

30

A lot of surfing terms are unquantified, and I guess unquantifiable to a point, because of the variations of personal opinion, the variations of waves, the variations of people, styles, board designs, the list goes on.

And then there’s just the plain meaning of the word. ‘Drive’ is just a word. It’s a verb, a noun, and an adjective, so interpretations are different. ‘Thrust’ is another one that’s open to interpretation, again a verb, a noun, and an adjective. A lot of comments above use the word in all three contexts, so not always comparable in finding a unified definition.

Personally I prefer ‘drive’ to ‘thrust’. I’ve never thrusted around a section, but I’ve driven around a section. I’ve done driving bottom turns, but I’ve never done thrusting bottom turns. I’ve even driven off the top, but I’ve never thrusted off the top. So I prefer the word drive in this context.

Also, in some cases I drove the turn, and in other cases my board drove through the turn. Depended on mood, board, waves. Sometimes I wanted to drive and my board wouldn’t (thus learning how to design properly), and other time the board felt like it was driving itself and I just had to hang on.

I have however done a driving turn and been thrust out of the turn and off the back of a wave. But I also paddled back out and prepared myself and out of the bottom turn I then drove off the top. Ended up way out in front of the wave, but you can drive off the top, so drive is not confined to one part of the wave.

Yes, the bottom turn is probably the most essential turn where drive is sought, and attained, but only one proponent of riding a wave and driving all over it. Actually that’s what I reckon, drive all over it.

Do you ride a board? Or do you drive a board?

I drive my car, from when I start it up to when I turn it off, I’m controlling it. But the whole time I ride in it. It thrusts me along the road.

So I’m actually driving my board from take-off to flick-out. Now where is the definition of drive?

31

I like the term drive. That’s what it feels like to me.

I’m noexpert. I’m really ignorant when it comes to hydrodynamics, but I know what I feel and like and I love “drive” in a board.

So thinking about this afternoon I think I came to some simplistic surmises. When you go straight down a steep wave, gravity takes you there, basically. When you take a highline, you are surfing the forward rail and fins on the open face of the wave. When you take that vector between the two, the fins and rear rail on the engaged side become critical, and speed really (it seems to me) picks up. Have you ever been on a steep wave and felt your fins tweaking like they might break? That’s what I’m talking about when I say drive, just before that point. You are flying! I think it’s because you’re tapping into the energy of the wave right at or before the trough, where the wave is really making it’s most radical leap from horizontal to vertical. When I surf I sometimes think of a guitar string: like you’re humming up and down along this critical but invisible line of energy.

Does that sound right?

Good weekends my friends. Peace, C

32

… the sensation of drive

This thread may not help get the bubbles out, but it may put some physics behind a sensation. And if you’ve got the physics, a design or design tweak maybe close by.

You can’t measure ‘drive’ as it’s being used here, it’s a quality. You can measure what’s producing the sensation – and that’s acceleration. But not all acceleration is ‘drive’. Drive seems to refer to a smooth and uninterrupted kind of acceleration – smooth and uninterrupted being key.

Regarding smooth and uninterrupted, an analogy might be stepping on the gas in your car. Unless you’re driving my car which chugs and jerks, the climb in velocity tends to be smooth, at least between shifts.

Acceleration is about changing velocity. Velocity can change when its magnitude changes, or its direction changes. Velocity without a particular direction associated with it is called speed.

When you make a turn, you don’t necessarily change your speed, but you do change direction and hence acceleration is required – a centripetal force, or centripetal acceleration is required. Along with the pressure sensors in your body, in the skin, feet, legs, joints, there all over the place, an organ called the otolith of the inner ear, will pick it all up and tell you something is changing. Your brain will also report back on its quality, among other things.

But it doesn’t have to be a turn, depending on its nature, a sense of continuous unbroken engagement will also do the trick. Waves as they head for the beach are all about acceleration. Prior to breaking the wave form itself is continuously slowing in the direction of propagation, yet the flow up the face is continuously increasing – any sense of continuous and controlled engagement, or using balsa’s term ‘hold’, is bound to evoke a sense of ‘drive’.

Smooth and uninterrupted is desirable, it feeds that sense of being in control. The right board, for a given technique and set of conditions is likely to potentiate a feeling of drive during certain maneuvers, in as much as it will provide the means to pull off a maneuver in a smooth and uninterrupted manner.

What design makes for ‘smooth and uninterrupted’ accelerations? This is the shaper’s problem, or the design problem, and a lot of the design elements which can be in play have been addressed by others above.

As I mentioned in a prior post, I’ve never been one to use the term, but whenever I’ve heard or read the term one thing has been clear, that something was ‘right’, something or things fell into place and produced some magic - and it’s my guess that magic came in the form of a controlled smooth and uninterrupted acceleration – and who wouldn’t love that.

kc

33

Drive and engagement may be thought of synonymously or not as you choose but there is significant merit and unifying these concepts because washout is loss of drive. Depending how a board is shaped it will tend to engage the wave face relatively more or less.

Looseness is freedom during the driving moment and the interchange between drive and wasout, Performance is the ability to change direction momentarily during the driving action or move from wash out to drive effectively while changing direction.

Board drive can be too far forward on a board and can make the board difficult to manage because it overcomes directional stability too quickly for the surfer to compensate as the wave changes. Fins usually have the greatest role in this condition. Also drive can be too far aft thus making the board stiff and very sluggish when directional changes are initiated by the surfer.

Board and fin foil, bottom configuration, rail configuration, rail rocker, bottom rocker, fin choice and fin placement all affect drive. Finding the balance is what the shaper and fin maker sculpt from their conceptions of what create differing performance perimeters. Our process continues and its variables stretch immeasurably forward and backward and the second part of this thought may be the more important. The beasts of the air and sea have much to teach.

Stay Stoked, Rich

34

Re: terms: lift and release work fine for me, in every aspect I’ve seen discussed on this thread. As subject to literary trance states as I am, all the poetics are nice, vs. physics, and Rich, you merge the two nicely, but I almost think drive is meant to be a vague term… when you want to design some drive and/or looseness into a board, you have to start thinking about lift and release though.

Paging Greg Griffin!

35

I like Swied’s skateboard/tick-tack analogy, but agree that tick-tacking in surfing terms is “pumping”; generating speed from a slow plane. Like Surfthis said about skating, “the drive is the force of the wheels against the pavement”. (Newton’s Laws of Motion: To every action there is an equal and opposite reaction.)

It’s a great place to start thinking about or understanding drive in simple terms… and for me drive (in surfing) would be maintaining or generating speed through motion, but in bigger arcs. Projecting out of these arcs/turns with even more speed and energy than going into them, through technique (surfer) and equipment (fins, rails, tail).

Harnessing the “force” or energy from the resistance through a turn by unloading into a smooth arc, and continuing these cycles of loading and unloading.

(Without turns or big arcs there can be no drive. Trimming down the line does not generate any energy… you’ll keep going faster until you reach ‘top speed’, but only by turning can you use that speed to generate more speed… drive. Ofcourse in surfing you have many elements in the mix: planing, the movement of water, angle of wave, equipment, etc; but all of this comes back to Newton’s Three Laws of Motion, which is pretty simple really.)

…

Besides trying to articulate the sensation of drive, I think the other question in this thread is: can you design surfboards that will improve the “ability to drive”?

If you start out with a board that planes better, fins that hold better through turns, rails that don’t dig or slow the board down when trimming (in other words shapes and angles that facilitate smooth motion and speed) you’re gonna have a board with the ability to drive better.

(I’ll leave the technical stuff to those with more experience and knowledge.)

36

Great thread by the way.
I love physics/natural philosophy without the mathematics. :slight_smile:

Really like Wildy’s “driving vs. riding” ideas; and C-Slug’s musings…

“When I surf I sometimes think of a guitar string: like you’re humming up and down along this critical but invisible line of energy.”

Brilliant!

37

**"I love physics/natural philosophy **without the mathematics."

I hear that…

38
My guess is; purchase (bite) + acceleration = drive. A hypothesis is; Using the same board, simply by changing to a bigger fin set-up will provide more drive, (the downside is less tight radius turning ability). And I'm not sure about that, it gets really complicated when you start to consider drive in relation to board foil, bottom contours, flex, etc.
Sickdog
39

This seems a bit too simplistic, but maybe is a good example of how one design feature affects drive - like fins or rail edges. But I would have to say that drive is a function of bite… there’s a direct relationship between the two. So they go on opposite sides of the equation…Greater bite = geater drive?

40

2Me

To me Drive and Carve mean “fully on rail/tail”, Pump is more subtle usually down the line or deep in the barrel kind of stuff

Drive = the first bottom turn of Barry Kanaiaupuni, Terry Fitzgerald, Jeff Hakman, Richard Schmidt and a select others at big Sunset Beach.

Carve = Taylor Knox, Richard Cram making turns of the top, shoulder and bottom. (Curren at J Bay on a Mckee Quad in the the first search video)

Drive + Carve = Laird Hamilton at Super Large Peahi Christmas Swell 200??

Pump = Dane K (deep at Backdoor)

I think when Curren introduced the multistaged/sequenced top turn it took a little out of the fully committed deep rail engaged “carve” that was being done earlier but it was a more dependable style.

then again what do I know I’m just an observer here(since '67)