Rudimentary Theory

General Discussion
1

Hello All,

I saw this quote on a thread not too long ago:

“having a rudimentary understanding of boards and waves and what one is trying to accomplish in their surfing will allow them to safely purchase a “stock” board”

I approached this someone, and I asked him if he could write a short ‘summary’ of sorts as to what a rudimentary understanding of boards and waves would encompass. He generously responded in that he would try to answer, if I started a thread about it, so here goes

I can always stand to be educated, so I would like to hear what people’s takes are on what encompasses a rudimentary understanding of surfboards and waves, and how to apply that to what someone is trying to do with their surfing.

This thread can stay as simple or get as complex as you like, but the BBB (Bare Bones Basics) would be great to start with.

I have a million questions, and every one of them could be followed up with a ‘why do you think that?’, but for now, I would just like to hear what people think, the whys can come later.

For all you know, maybe we can begin to ‘meld’ different ways of thinking to come up with a ‘treatise’ of sorts (sort of being able to explain and decipher Mr Loehr’s Theory of Balance and see how it compares to another theory; I bet they would be very similar, but just use differing terminology) , but now I know I’m getting ahead of myself.

So, let’s start with basics.

Who’s first?

JSS

PS - Some ground rules: Please no picking apart of anyone’s thoughts or theories with any malice. We are here to find out a good explanation for the facts as we currently misinterpret them (aka ‘science’, or Latin for ‘to know’), not to be ‘king of the hill/thread’. If you happen to differ, SAY WHY and do it cordially, and ask the person you are questioning for a response. This way, we can all learn something, and no one gets burned or discouraged. Also, if you can, please take the time to formulate and post your own theories if they differ, don’t just knock a sand castle down becasue it is easier than building one.

PPS - If the thread runs its course well, I will offer to summarize it and try to put it all together into a basic, rudimentary theory of surfcraft (of sorts), or at least ‘a beginner’s guide to picking a board for the stuff you want to do’.

2

I have a theory, and this can apply to almost anything. And that is: That the simplest of concepts (e.g. man on board/stick/plank with no moving parts planing across surface of wave) have the most unbelievably complicated design nuances, while the opposite is also true.

3

Have you checked out http://www.sticktheory.com/index.php?title=Main_Page ?

(Are you at Tech or LCU? I would guess Tech, but I knew a girl that went to the latter, and your handle made me wonder.)

4

Becoming proficient at riding many sizes and styles of surfboards will make choosing one off the rack even easier.

5

Hey janklow,

No, I hadn’t seen the site, will have to check it out. I am at Tech, and the handle comes from the reporter that Robert Duvall plays in the movie ‘The Natural’. His name was Max Mercy, and I thought it sounded cooler than ‘Roy Hobbs’ (played by Robert Redford). But I love that movie, cheesy as it may be.

JSS

6

PRIMARY THINGS ONE NEEDS TO KNOW

[indent]Riders Size & Ability

Wave Type & Size

[/indent]PRIMARY THINGS ONE NEEDS TO ADJUST[indent]Rocker

Template

Volume

[/indent]These are the basics from which the “Right” board can be distilled.

The sooner one figures these out the sooner one can achieve security in their board choices.

7

Elements must be balanced

Any single element that is too strong (rocker, wings, fins, thinness, etc.) that is too strong will manifest its dominance at the worst possible moments.

8

Hey what about tail shape!

I hear bat tails makes surfboards go much better.

:slight_smile:

Seriously…

just to add; the riders style is important.

And proper finning.

My preference is distinguishing between features that maximize lift/speed v. features that add stickyness/control.

For example, you can design a really fast flighty board thats hard to handle and get back control with proper finning.

9

to me it seems like a great board is like an ecosystem in harmonius balance. if you remove or interfere with a single variable of that system you destroy the harmony and the board goes to hell

10

Sandy, wow, wonderful analogy

11

Alright, a framework. Cool, thanks Bill.

Let’s divide each of your preliminary variables into categories, and then see if you think they have enough variation, and go from there:

Rider Size: How about 3 sizes: below 150 lbs, 150-200lbs, over 200lbs. Maybe more are necessary, but the fewer categories each variable has, the less permutations to deal with.

Rider Ability: How about 3 categories: Beginner, Intermediate, Accomplished/Advanced. Beginners are people from never-evers to the ability to ride a wave in perpendicular to shore consistently. Intermediates can be people who can ride ahead of the curl, all the way to cross-stepping, trimming, gentle top and bottom turns. Accomplished surfers are just that, beyond the ability of Intermediates, and probably focus on a certain style, or developing a ‘quiver’ of styles/maneuvers.

Wave Size: Three categories sound good to me here as well: Under waist high (3’ or less wave face height), waist to head (6’ or less), Overhead (6’ + faces).

Wave Type: This one has several components, but here’s a shot at trying to compile. Split this one into 2 categories, with 2 choices each:

 1. Wave breaking speed:  The speed at which the curl moves laterally (as seen from shore) across.  I guess slow and fast, but this is incredibly subject to rider's ability and perception.  One person's 'fast' could be another's 'slow'. 

 2. Wave shape:  Spilling (mush) vs Plunging (very hollow, pitching) are the endpoints of the continuum, as surging wavetypes cannot really be ridden, as far as I know.

So, what would be the best way to proceed? Defining a couple of sets of avriables that are different, or discussing how the basic board variables (rocker/template/volume) change for a change in each category?

Let me know if this is too vague, too complicated, or an adequate starting point…

If anyone sees any huge discrepancies, please let me know.

Please keep in mind that this is to describe a bare bones basics rudimentary knowledge base, not anything overly complex. I realize most of you guys have all of this knowledge already in your head, but I want to see the thought process and the why’s behind the how’s…

JSS

12

Bro, you gotta have a bat-tail and deck channels bro. Those are sweeeet.

Seriously. rocker and fins and their placement are the most important variables. Then everything else.

13

I dig the Bat Channels too!

14
Quote:

Sandy, wow, wonderful analogy

i listened in biology when at school :slight_smile: maybe some of you have read this essay on surfboard design. can’t recall where i got it or who penned it, but it opened my eyes to a lot of design features i never knew about. get it from

http://www.mytempdir.com/2017545

15

Bill put it well…

For sure, rider experience/fitness/style (and by style, I mean what they want the board to be able to do well), and type/size of waves the board is meant to be ridden in most, are the greatest determining factors in board design. If you can match those two things, you’ll have happy surfers. That’s where the “harmony” lies, in my mind.

The only thing I’d say differently than Bill, when it comes to what you need to adjust, is I’d substitue bottom design for rocker…

…which is a tough one, because they’re so intimately tied together.

Template (particularly lenght, but most certainly including outline curves and widths), volume (to match rider experience/fitness/style, and includes rail volume), and bottom design (which includes rocker, rail profile and fin choice/setup), are the major design factors the shaper needs to adjust to create a vehicle that that creates harmony between wave and rider.

16

Don’t bash the bat…they work. To me they feel like a cross between a swallow and a squash.

Even battails on the trailing edges of fins work. No kidding… Ever try it?

Why? Who knows… we haven’t figured that one out yet. I think it has to do with decreasing surface area (or template area on fins, I guess) but still maintaining tail width at the leading edge of the front fins.

But this is a different thread…

17
Quote:

The only thing I’d say differently than Bill, when it comes to what you need to adjust, is I’d substitue bottom design for rocker…

I think good rocker is more important than nice concaves. Flat bottoms with good rockers always work. Crap rockers and any amount of concaves won’t do you squat imho…

If the rocker is wrong how can the bottom contours be made in the first place? Concaves and v are derived from the rocker in the first place right? (or did I really miss it???)

Rocker is difficult to get my head around and even more difficult to make work correctly I can only assume that it takes a lot of experience to truly grasp it and how it works with the other design elements. Where I am we simply don’t get enough days in the water to get to that level… so mostly we borrow, beg and steal rocker lines from boards we know to work and sometimes try to play with those…

But flat bottoms are a good place to start if you have a decent rocker …

18

I’ve just done a bit maths while trying to get my head round my next board, based on flat plate planing theory I worked back to get the angle of attack required to get me DTL on my board in 4’ waves, the answer is just 1degree. Now the coefficient of lift for a flat plate changes by 25% to 35% for a 0.25degree change either side of that 1degree. 0.25degrees equals about 4mm over 1m or about 3/16’ over 3’. Obviousley I had to make some pretty basic assumptions but my rudimentary theory would be that little changes make huge differences.

19

Hey Dunk,

With flat plates, I am not surprised. They have very small/tight performance envelopes. That’s why with rocker curve, you can essentially offer the flow a continuosly variable curve that approximates the narrow flat plate angles over a larger angle of attack range. It’s a compromise that has to be made based on the fact that it would be very difficult for a person to maintain a 0.25 degree or smaller tolerance in hull AOA for a flat plate, but add rocker and that tolerance increases, I think. Does that make sense?

The best analogy I can offer is that of trim tabs on large, high speed boats. The trim tabs have a small area compared to the entire hull, and are adjusted over relatively small angles, but have a dramatic differece in the performance of the boat. They help keep the rest of the hull in that tight performance AOA band.

If I am wrong, please correct me, but I think this is correct.

JSS

20

Ummmm, BB and MM"

Let’s go back a step becuz you wanted some basics, yes? (or as the French say, no?)

How about this one for rudimentary: a given weight of rider has a greater affect/effect over a given area. The smaller the board area the greater the affect (therefore effect), the larger the (board) area, the less the…

Pretty basic but ultimately true w/out a goobly gook of other considerations.

Everything has weight, mass and volume…rudimentary enuff?!