what creates drive ?

Gravity has it's part to play in creating speed. Not sure if that helps.

Twin keels, six or so inch butt crack, 11 inches or so between the tips?   Mike

Briefly,

Getting to the question

Since you didn't provide your own definition, I'll go with mine. Drive in this context is a reference to the quality of an acceleration, in particular a continuous controlled acceleration, rather than a jerky and/or less controllable or less predictable one.

Gaining or loosing...

Surfing has a sort of duty-cycle; in general, part of the time your gaining energy, and the other part of the time, your loosing energy, sprinkled with moments when the two balance.

Unlike objects hurling about in outer space, a object moving with a constant velocity in a viscous medium, if only partially submerged requires a force. So even if you're moving with a constant velocity, you will be both acquiring and burning energy to do so.

Half the story...Sources of energy*

There are three basic sources of energy available to the surfer surfing on a wave: what he brings with him; the kinetic energy inherent in flow of water; and, the planet's gravitational field.

You may see your surfing style as turning a lot, but even if done smoothly and seamlessly, one maneuver to the next, you will be cycling through this duty cycle. And if you're gaining energy, that energy is coming from one of the three sources mentioned in the last paragraph.

Acceleration

But energy is not acceleration. Energy is just a form of accounting, it doesn't exist. It has no pure form. It is always associated with something like a force or relative motion. So the above reference to three sources of energy could have been termed instead as three basic “forces”: whatever force the surfer himself can bring to bare biomechanically; the forces developed from changes in the momentum of the flow of water; and, the force associated with the gravitational field.

Since force defined as mass times acceleration, all can play a role in drive, and surfboard design or mechanical design in general, can be used to both harness and control each, to the extent that each can be respectively harnessed and controlled.

Perception

A given surfboard which seemingly provides one surfer with all the necessary tools to harness and control these forces, may seem less so to another. This isn't just a matter of skill level, but technique too. This relates back to the use of the term drive, not all are guaranteed to experience it on similar equipment, let alone experience it to the same degree. This is obviously important, particularly with regards to the role of technique. Given the way some surfer surfs, he may find that a certain design element seems to provide him with this sense of drive at the right times. That same design element viewed as less important, if at all, in providing a sense of drive by another surfer.

Getting back to the question

So the question becomes, who's the market. And 'who' includes conditions, and technique. So define the market. Is it a market that wants to rip up slower mushier smallish 3-4 ft waves? Or a market that wants to survive and maybe get a little more done on 40-60 ft waves? Or any number of other scenarios.

Once the market is known, you can then start the trade-off exercise.

kc

*the other half of the story is energy sinks, or ways of dissipating energy, all of which are critical in design... but like I wrote at the beginning of the post "Briefly, "

I'm not sure fitting-in is all that desirable. In fact, the essence of surfing is about not fitting-in.

In my post to jimthesaint I stated the three sources of energy, or three basic forces. The one which defines surfing, or puts surfing in a separate class is the second one listed: in terms of force, the forces developed from changes in the momentum of the flow of water. Predominately, this take the form of the forces developed during planing – a partially submerge object in some fluid, colliding with the flow of that fluid. So getting in the way of that flow is critical.

I would argue that surfboards really aren't design to fit into the curvature of a wave face, but to exploit that curvature in order to generate force. The 'attack' in angle-of-attack suggests as much, without it I'm not sure what you have.

As I also wrote in my response to jimthesaint that you are either gaining or loosing energy when surfing. This is true because water is a viscous medium. So even if you're trimming in a barrel, you're burning energy, and that energy is coming from somewhere, and in that case from the colliding water on the bottom of your board.

If you fit in you are 'not making trouble' so to speak, that is you are not colliding with the flow, and if you're not colliding with the flow, you are loosing energy.

Design is about providing the surfer with right tools to 'not fit-in'.

kc