theory of a fast rocker....

Folks- I am gathering info while still traveling on my trip to cali to visit with folks. Anyhow, in my time off I thought hard about what type of board and rocker combo I want.

Here’s my idea:

The concept is about the creation of a drivey- yet magic rocker that has my board tipped over seriously-yet under utmost control…
My idea is to - use the long rocker stick we all read about and press my finger with light finger pressure to determine my apex of center of blank. Then I will place my plan shapes wp there also, and build around from there for my end length etc…
I figure I need to cut or feather in nose and tail rocker, so I figure I willl have my start and end points about 1/3 way from nose down towards center- same with tail- go 1/3 way up… Whick in turn will leave me with my apex at center of stance…
So I figure I will end up with a relately flatter curve in center of my rocker or apex…ofcourse I’ll blend my nose and tail curves into my apex curve or hight point in center…
Now for my idea I read about! I will now flatten the middle apex a bit to increase speed.
Also, I’ve been told by a well repected shaper I had inquired about the matter who informed me I don’t want it ‘dead flat’ as it would prob be too stiff.not to mension more prone to breaking maaybe…
Anyhow, off the top of my head I’m thinking when I do this mod it’ll widen my apex a bit, but wth!? Board should be faster. I figure my apex area will prob end up as a 24" plus radius of sorts “centered”@ my wp. Does any of this make sense? Also, debating making a rocker template(yay or nay)? Tia to you folks- be you guru or enthusiastic biy’r.
Tail rocker I’m guestimating a inch and a half, nose rocker 3" to 3.5" what is your recommendation?
Foil I’m thinking 1.5" or so a foot down from tail, and maybe same in nose a foot down from tip? Just plans b 4 I chew into da foam! with myyyy gooood old p20sb hitachi I bought!!!

…well, what you need now is a concept.

Think about the overall design of your future shape; the planshape, what type of board

And for what the board will be intended.

Good idea! Yup I need to nail that down… But I’m getting close. I’m re-working a curve in my plan shape that’s work ‘in progress.’ All I have to do is fix one curve, the tail is a pulled in fish that will be kinda pivoty in the turns…
Fyi- on my custom board I had shaped-which I got my idea for my personal board I will shape will have an 8" wide fish tail.
But there’s gotta be something I can do to lessen the "side effect"I got on steep shoulder hops? Wierdly my board felt as if it slid sideways down the face and did that old elevator sideslip… Not sure why? Would my pulled in tail cause this?

Board is intended for small to double overhead.

Oops, I forgot my deck rocker… I think that too has to follow , or compliment my over all foil and rocker on bottom…I’ll figure that part once I tear into my bottom rocker and thickness.


On a board I did my first time with pp/power planer I inadvertantly went 'hog wild’on nose flip/rocker… The result: just a few slivers too much rocker that caused board to a. Paddle poorly B. Felt a bit slow.

The solution- basically was to- shape in LESS nose rocker! So this is where I’m at now. Prob not a biggie to a advanced shaper? But to myself its a break through! So on my next board I will pay strict attn to the 6" past or so area, or the foot down nose to 24" point, or “entry rocker”
Area there in 24" or so in front of the wp… Well, in this critical zone- the ‘command center’ I’ll leave the curve a bit lower than where I went. Again, I cut in too much nose rocker. And too much nose flip is prob not good -even on a big wave board? Too much is prob not good.
Some feedback from actual surfing:

I surfed carmel beach and I think marina beach? Board surfed, but felt slow at paddling(pushed water a bit). Board also felt like it was slower than what I’m used to. This I attributed to my overkill on nose flip/rocker. And I knew it after the fact! Ofcourse I knew the damage was irreversable as one cannot replace foam that has already been taken… So let’s shape with utmost caution. And always “measure twice-cut once.”
Live & learn. Anyhow, my board would take off- felt stable- drove down the face, turned ok. But def did not have the magic. Ok, ok- you all know what I was after… A magic board! Aren’t we all… Wish me luck folks! I’m about to shape my magic surfboard!!!


I’m not trying to be a dick, but do you have the skill to shape in all the nuances discussed above?  I don’t.  My advice is find a board you like that lets you surf the way you like and take some measurements with your rocker stick.  Try to find a blank somewhere close the the measurements and follow the rocker curve of the blank.  Tweak the nose and tail rockers if needed.  You’ll get a board that works pretty well for most recreational surfers.  I’m at C.B.(it hurts to even mention the initials) almost every weekend and more.  If you see a middle aged guy surfing goofy home made boards come say hello and we’ll talk.  Good luck.  Mike

Do I know all of the nuances? Not totally. Some I do, some is theory to be tested. Well see. No offence taken.

rooster I am sending you a rocker modulating device by the 

plasket teleporter if you have time please pass this along to

Dr. shapeatonic 2011.This complex decoder ring should

rectify these complex measurement co - efficients.Furthermore

to tape the ring onto the power planer should make the absense

of the CNC accuracy  neutralize.I thinque after enough hours of close

scrutiny these concerns for an ultimately per-fact speed board will be 

supplanted by one good wave with a perfect take off 

followed by a timely and full-filling pull-out.

blessings to you dr Shape and may

your concerns be reduced

as the spring turns

to summer.




traveling to california

gives one lots of time to think

imagine what it was like

when It took 3 months

from missouri on a covered wagon

without a laptop that wasn’t a 2 year old child.

Hi shapaholic2011 -

I'm not trying to be a dick either. 

I would not get too hung up on any single component of the design.  Something seemingly simple like rocker can be broken down to an infinite number of variables.  I think there was a thread here on Swaylocks regarding "apex."  It was discussed to death with surprisingly little agreement.

More important than any single component is how they are all balanced and blended around your stance, style and ocean conditions.

I've said before that for every single design component you change, I can likely change some other components to give a net result of zero... I.E. the overall ride remains the same. 

For example, If you boost nose rocker, I can probably widen the tail, move the rail foil aft and tweak the tail rocker to negate the nose rocker increase.  By changing the overall balance of the rocker, outline and foil you can impart significant changes in the ride. 

Another example might be a narrowed tail combined with increased nose rocker and thinned aft foil likely resulting in a tail dragger in anything but a grinding tube.

Those examples don't even begin to address fins and fin lay out.

In theory, flatter is faster (in a test tank it is) but in actual day to day riding variables, there has to be a proper blend of all your design components for the optimum ride. 

Basing your impressions on rocker alone might be oversimplifying things.

Mr Mellor, you are a voice of reason in a sea of conjecture and hysteria. Very Well Stated!

Gentlemen- ty for the tips! And- Johnmellor, what do you mean by
Move the rail foil aft? Sorry I don’t know the terminology? Do you mean move the apex into a new position and blend nose and tail rocker from there?
If so, I kinda get it. I prob need to re-read your tips, but thanks! I need all the info I can get b 4 I pick up blank. The plan is to make a ‘magic board’ that feels alive under my feet.

blank > old clark 8 5 w/natural rocker for thicker board

8 5 a for thinner,quite gun  speed friendly





**erall Bottom Length: **8’ “ (21.2 cm) **Tip-to-tip Deck Length: **8’  1/1” (28.0 cm) **Maximum Width: **22 1/1 (.0 cm) **Maximum Thickness: ** /1 (8. cm) **Displacement: **2.9 ft3 (.0 L) **Introduced: **September 200

**Rockers: **Natural / +1/T2 **Shaper's Comments: **This newly made 8’’’A blank was lengthened to easily net an 8’’’ bottom length. I redesigned the rail shape for less waste and stronger foam. I also widened the nose @12 by 1⁄2”, as well as pumping the max thickness up to  /8”, as to be a more useful blank in this size/volume range. The new natural rocker in this mold design is the 8’’’A +1⁄2” nose, +/8” tail. This rocker being shaped in instead of glued up, will allow for a much more accurate finished rocker, due to no “spring back.” I have the old 8’’’A natural rocker if anyone still wants it. All the “A” series of blanks are designed to take the majority of thickness of the bottom, leaving small adjustments in the nose and tail rocker and their thicknesses. This blank can be ordered wider or narrower as to allow for stronger decks/rails near the perimeter of the board outline, and less waste.

Hi -

Sorry, that didn't come out quite the way I intended.  I meant by moving the fat part of the rail foil aft, the result would be a shift in balance to the rear.  

Regarding blank choices, your best bet is to find something as close to the desired finished product as possible.  This will avoid common pitfalls like overshaping and messing up rocker/thickness that has been designed in to the blank by an expert.  For more speed, if there is more than one choice, choose the flatter rocker.

A wider tail tends to make a board feel more lively - especially in slower surf.  Check the current thread on the Nugget.  I think the tail width is somewhere in the neighborhood of 18"+.  That's really wide relatively speaking and some guys are loving it. 



Hello John,

And thanks for the tips! I’ll take your advice and grab a blank close to my end shape. The boards going to be a larger fish design. And I prob should order a fish style blank-to keep the shaping minimal.

As for the thick center chunk on blank if I put that part at my wp in stance I take it that would be my balance point, right? But from what you hinted to I could put it center, forward or towards the back a bit depending on style of surfing or stance. So if I place my thick part forward center I take it board would have a drivey feel vs a pivoty feel if I placed the thick part back or @ center? Fair enough! I geuss I’ll just put it behind center a bit- how does 4" sound!? Or 4" behind center? Fyi- this would be on a fish design- a twin fin. A bigger fish at 6’4" and 21" wide. Question: if I put it back 4" will it make for a more pivoty turn? Cuz I want it to be responsive in turns. Tia
Question: will it matter if my wp of plan shape is forward? The reason I ask is I’m 2/3 way done on my fish template I’m making with a bendie rular I got @ home depot. I just need to re-design the nose half. Got some thumb tacks and nails to help me line her up - since I don’t have a hoider. Dimensions 15" nose , wp forward 2", tail 14.5" , tail 8" at rear with fish cut 4" deep. Hope it works as planned! Thanks to all who leave their tips !

dont eat the yellow snow…your welcome!

Well, I looked over my notes, and according to tips I got from a established shaper- he recommends I place this ‘thick’ part or apex under my stance for ideal results for out of respect—i’ll try this first. But I’ll try some you folk’s ideas as well as I’m going to grab 2 blanks. One a 6’5" and the other a 6’2". But I do appraciate all the tips man!thank you!
That said, I’ve tried all kinds of boards so I’m very open to ideas! I should mension I built a 5’9" tri fin thruster awile back, and I cut off about almost a foot off the rear end of blank(from a tip) to retain a lot of nose flip in said blank… Built said board and it worked very well! My geuss is: I must have changed the apex to fit in with my newly situated apex or thick point.
But do keep ideas coming! Like I said, I’m pickin up 2 blanks atleast. Second board I’m thinking of doing some sort of modern shortboard? Not sure what I will do on #2? Night.


Of course I have time and would be happy to pass the modulator to shapa.  Please include an extra rocker modulator for my planer, too.  Polished aluminininuiium.  Mike

Greetings, Jim here!

So why are you sharing this info of blank w/me? Sorry for my confusion, but I’m on a blackberry trying to read posts!?! JIm :confused:

I had no idea 

you were

using a black 

berry,Blank info

was for a much

bigger screen

and conceptual

bigger board.

cutting a foot

of a blank disrupts

rocker and foil


boards this short

and such close

tolerance molds

make % margin

for error critical.


cut disproportionate

length off the tail

will definitely result

in too much nose rocker

push water and no

thickness to shape

out of the apex

center.close tolerance 

hp short board

blanks are not as tollerant

as big ol’ fat 8’5’s


make a 7’6 out of an 8’5

you still have 3/4’’ to adjust 

the apex. a 6’4 what 3/16’'?

While ambrose is correct that lopping off a big piece of a blank will create a lot of re-foiling work, I want clear up a little misconception about ''following the blank rocker''. Most PU blanks are designed for a little bit of versatility, especially nowadays since no manufacturer offers the 70-something plugs that Clark used to produce. That means the plugs are a slightly thicker at the tips (and maybe overall). Usually the designer adds this on the bottom, so the ''natural'' rocker is flatter than intended yield. Also, ''natural'' rocker in the context of blank plugs only refers to the rocker that comes out of the mold. PU blanks are split and stringered after molding, and rocker changes are made at that point. Since flattening a blank often produces distortion in the deckside, most rocker changes in glue-up are additions rather than subtractions. IOW, blanks are designed a little flatter than what most pro shapers are going to yield from them, so ''following the blank'' isn't going to get some magic curve straight from a respected designer. The blanks are designed to accept custom rocker changes (which are mostly + rocker).

There are exceptions to this, there are/were a few blanks that have/had a great bottom curve right out of the mold. But by and large this is how it works. Especially today, in the CNC age, versatility and ease of ''fitting'' to files trumps molding a ''ready to go'' bottom curve.

Gentlemen- no- worries… It was only an experiment I tried cutting the piece oFf blank… Besides the blank was huge and I designed a short, short board… And since then I center it first… But ty for input.