Circular Rocker

General Discussion
1

Hey y’all!

It’s been a while since I’ve done any surfboard design and construction but I want to start again.

I want to build a midlentgh surfboard around 7’6" that is suitable for beginners. The one I had got stolen and needs to be replaced.

I’m thinking of using a circular line as rocker curve with just a bit of flip in the nose. Does that make sense?

The intention is to use a single circle all the way fom the tail to just before the nose (maybe the last foot).

Where would you guys start the flip in the nose and what numbers would you suggest for tail and nose rocker?

Thanks for your replys!

 

edit: I can’t reply to my own thread. do I need more points?

2

I would start looking around

base r=45-50’

nose r=4’

tail r=15-20’ (or very different depending on approach)

all approximate, depend on your other curves and style, subject to blending and inaccuracy.

It may be possible to draw a 40-50’ radius circle accurately, but it’s pretty easy to just bend battens or copy a rocker that works. If you prefer blending circles you could also use a lot more than 3, if you want.

Or, ask stretch…

3

Yes, more points. +1

EPS?

 

 

4

Maybe Yorky will chime in on this.  He’s done a fair amount of work with this idea.

5

in the early 60’s John Peck rode a constant rocker, his take was, as you move around the board you don’t get a sweet spot.

I built a 50th anniversary balsa blank for Hobie. they gave me a rocker template, other than thickness change, the deck and bottom curves were interchangible

6

Jim - what’s your take on it?.. Or maybe on rocker in general ( or as it pertains to classic boards of the 60s) 

7

From the late 50’s to the early 60’s, the ‘‘natural rocker’’ of the day, was a holdover from the balsa era.      The best, and most desired rocker, was 4 inches nose and 4 inches tail.      This was for boards in the 9 to 10 foot size range.        Shorter boards ran up to an inch less, nose and tail.        Frankly, those numbers still work well today.        Just depends on the kind of surfing you want to do, as well as the kind of waves you are targeting.

8

rocker is the foremost important aspect of creating a well riding board, outline is very close to the last thing and fin placement, shape , size is second. I might be well off base, but I think it was Terry Fitzgerald that said he could make any board ride better by working on the fin(s) arrangement

9

outline,

outline is very close to the last thing? (of importance??)

What length/shape of board are we talking about.

Much respect.

10

After abouthalf a dozen boards where the template and fins were kept pretty constant, and rocker was closely done, with vacuum bagging to a rocker table, a couple of thoughts came out.

There are three areas of rocker. Nose, middle, and tail.

After the paddle, and the drop, nose doesn’t matter much. A six foot radius will keep you happy.

The middle and tail curves can be switched. Meaning the middle can have a forty foot radius, and the tail can have a twenty foot radius, or mid can be twenty and tail forty, and both can have a 2 1/2" tail measurement.

If the mid is the forty, and the tail is the twenty, it will go down the line fast, but won’t turn worth a poop. Think 1970’s early shortboards. You will loose some glide and speed, but really increase turning if you switch the numbers to forty foot radius, twenty foot radius tail.

Percentage wise, nose rocker should be the front 25% of the board, then 40% middle rocker, and 35% tail rocker.

Smooth transitions go faster and smoother, while a kink between the middle and tail sections will cost you some speed, but will give you a pivot point.

11

all boards, today’s younger set of designer/ shapers have left the track of symmetry as being utmost importance.

The rush to build Tomo style, asymms, Simmon’s, Alaia’s, finless, etc. are having them concentrate on bottoms rather than out line. Sure a pig style of any length board will affect the turning radiius, as will shoving the wide point forward, but in general, a badly designed rocker will be very difficult to remidy with fins and outline.

Kurt Wilson, Xtrak owner, APS rookie of the year rode for me through the 70’s and 80’s, he had me pull his wide point back to center in the later 70’s, while nearly every surfer on the planet was riding wide point forward. I then took on the challenge of rockers, Mike Daniel was working at my factory and was witness to us getting more than a leg up on the rest of the builders.

Only Greg Loehr was working with extreme bottom rockers with Bil Hartley, leading to Kelly’s flip tips, which Mike Daniel designed and built 2 plugs for Clark, the 6’7" D and the 7’2"D.

Since then, with boards getting below 6 feet the need for a lot of rocker is pointless, the surfer has complete control over his platform, a simple weight shift and the nose lifts up or down, so a lot of nose rocker is no ,longer  critical on steep drops and being short, the rider can power the board through turns without the need for very much tail rocker. Many of the steep drops are controlled with a rail grab, tis has lead to the noses and tail getting wider also, on a 5’7" board there isn’t much room to be 19" at center and have an 11" nose, it can be done, but there just isn’t the need on a modern short board.

That is what is so bitchin about the continuing evolution of the surfboard, it does not stay static, it is in a steady flux, some “advancements” turn out to be evolutionary dead ends, nothing new about that, but we have ridden them all and ripped on dinosaur boards, if I live another 10 years, I’m looking to see where this journey will lead

12

we thank you

 

13

Thanks! for your thoughts on the topic.

It seems I should go for a bit mor curve in the tail. Although I’m pretty sure I read that yorky uses a continous circle all through the tail in one of his carbon strand art pieces.

@everysurfer: your 3-stage rocker sounds pretty good. can you tell me for which length of board you’d use these radii? Seems like the dimensions you gave (20, 40 6) will yield a rather extreme rocker for a mid legth funboard( nose rocker~5.4" tail rocker 3.25").

I assume these dimensions are for a shorter board of around 6’0" and scaled the the radii to the 7’6" I’m aiming for. This brought me to a nose rocker of 5.6" and a tail rocker of 2.5". That looks pretty good.

14

quick reply as i’m sick with the flu, so is my whole family.

I always used an ark rocker as a platform to work from. 

Yeah I use it sometimes off the tail with novelty builds (like the carbon things) I added release points with tail shape wing, pod. The bottom design had increasing curves running through the channels with those boards.

I’m talking performance shortboards. 22ft rail rocker, kick the tail rocker (about 1/4" more or less) starting in front of the thruster fins and kick it at the front foot or a few inches forward, (deepest concave at side fins) this should allow you to utalise your 22ft ark along the stringer line for a longer smoother ark. or use a 20ft stringer line with less concaves or 24ft for deeper.

If you, or anyone likes late drops (or is haveing a bit of trouble making them) kick the rail at the front foot both rail line and ever so slight on the stringer line. Your front foot just melts into the board, still kick the tail. Yes, If you just stand there on the face it will push a bit of water, but put a bit of zip in your surfing and the thing will get on plane and fly (thrusters are designed to go rail to rail anyway)

…That carbon thread is just a bit of fun, I’d like to kick it off again soon.

Ark curves alone are kinda only guides for rockers… These curves are where the fun begins . Get a 44 gal drum, pull a tape measure out and tape/glue pen onto the ‘0’ end. Streatch it out and fix it to the drum. As you roll the tape around the drum you can make as many increasing cruves as you want… As the tape reaches the lower end the results will be a lot more useable. I’ve used painters drums among other things haha

It worked for me for years after high school, then I moved into computer generated mathematical curves lazer cut in 1.5mm plastic.

Now I can travel anywhere in the world without a single template and start making the same designs… good, if your a handshaper working in a country with out a working visa hahahaha kidding!, but now days. All you need is a thumb drive.

Use your arks for outlines, bevell lines, etc. coupled with a basic understanding of ratio, scaling boards up and down is easy. It’s all dot to dot.

Some would consider my shaping methods as ‘Not true hand shaping’ but I have converted a lot of shapers to my ratio/Ark method, even crusty old salt warts, back when I was younger and back when the machine wasn’t so bloody easy to bluff your way as a “shaper”

 

 

15

Sorry if it sounds like blar blar blar…

 

16

The forty foot and twenty foot dimensions are approximate and rounded for simplicity. I did a 6’8" where the main rocker was 68 feet and the tail was 26 feet radius.

17

Not blar at all.

18

wow, 68 feet (excuse me, but could that be diameter?), either way thats cool 26 off the tail (for me, is flat)

My Mal has a radius ark of 46ft middle, and increasing nose to tail.

cheers

19

This is a good thread.

So I went back to Satch’s dimensions and ran the built-in ‘funboard’ profile in BoardCAD which starts at the same length but is more rockered.

I dropped the bottom rocker to the nose/tail numbers mentioned. I did not mess with the curve of the nose, does it seem a bit ‘flipped’?

I took that profile out of BoardCAD as a DXF file nd ran it into Draftsight to see how the Bezier curves compared to radii. Pic below.

Seems like ES and Yorky are in the same church different pews.

Do you guys like to stage the rockers or keep them nice and blended all the way through?

Ignore the post count, I am still a newbie.

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