surfboard calculus


here is tha article i wrote.


Agreed.  Surfboard design is multi-variate.  Individual preferences being a huge variable.

Airplane wing foil design is driven by calculus.  But does this mean there is one perfect wing?  Too many different aircraft?  Nonetheless, designing effective wings would be a b!tch without math and science.

Like planers and routers, math and science can be powerful tools for the craftsmen who know how to use them…

Is there an equation that will get me the perfect surfboard everytime I shape??? That would be nice. My current ciphering is based on “naught + naught = doublenaught”

“There’s always math underlying beautiful design, both natural and manmade,” he said. “As far as mathematics is concerned, beyond the normal and obvious methods of measuring boards, there are relatively few people using any ‘real math’ in design. I know I’m not.” - Manuel Caro

Malaroo is the only one I know designing surfboards with math.

I suspect George Gall of PlusOne uses a touch of math.

Beyond the normal…

As a hobbyist, I currently design solely using simple math, with an aesthetic perspective.


So… when can Mr. Stoneburner use his infinite knowelge to become a Craftsman?.

Not gona happen…is it…?

Go for it Stoneburner. Use your Math and Science to build an awesome surfboard. Post photos and maybe a build thread. That sure would be great.


I never claimed to be a craftsman.  But George Gall is a craftsman, a mathematician and an engineer.

EDIT: Because Dingray felt the need to bump this thread today (Wed, 2018-01-10 13:34), I added a link to another post/thread:

You really are Stingray.


G Ratt…where have you been my friend? Water got warm the cold then warm. Did you hear about the plane crash at Warm Waters?    12 year old kid got a skull fracture…Wow…and we’re talking about math…

For my friend Stonny and my friend G Rat…Life is short…live it to the fullest !!!

My surf pal’s son gave me the full update. The kids friend got hit by the plane crash…Heavy…the only update I have is that surgery went well…Godspeed to everyone. Swaylocks is a good place…headed up north for a few days with the wife…Stingray…

Sadly and unbelievably I am still working on my surfboard geometry all day every day like an idiot, trying to get my business ready to start. People think I am mad and stupid and its all a waste of time and a waste of my life, (They maybe right) But I have come this far I have to get it out there and follow it through to completion. its one of my lifes missions.

Swaylocks contacted me today as Huck mentioned me today. Very respectful of you Huck. Thanks for that. So why can someone like me work on this for years and not get it going? A question I ask myself every day! Firstly I learned on primitive cad, uses Mac OS 9 classic as operating system. I was once a rich man and bought myself a CNC machine, set it up my garage on my rural property by the sea, and that could read the G code from the old system.

Now days (the poor days) I have to be able to use other peoples machines, AKU software, APS 3000 machine, but with that software I can’t go through my design process, its completely different controls and options, However Shape 3d will read modern engineering CAD files and translate them to AKU files. So I contacted Shape3d, they told me exactly how to do it, I tried that and it worked. So by designing with my method on a modern engineering CAD I can get files to AKU and therefore cut on an APS 3000 or any of those similar machines.

My skills on modern engineering CAD are a work in progress and my brain (it’s I play guitar not piano) has to forget the old methods and find the new, which I have done. The end result is far better than the old CAD. (trouble is I’m playing piano and have to think differently to make it work compared to playing guitar), but the boards are looking very slick.

If you don’t know already I design by surface intersection on 3D CAD, as the picture Huck posted shows. the more I look into it, the more I realize there is a right and wrong and a definite path to a related result. some things absolutely got me hooked. For example: By using a surface intersection method I found that a rhino chaser shape creates a classic rhino chaser fin. Believe me that was a life changing moment. It took me five years of going crazy trying to work out how to design fins, then one day I woke up tried this method and it worked. Couldn’t believe it. Still amazed.

The other thing was the plan shape coming from ellipse through a cylinder of board dimensions and then the deck and rocker curves coming from the planshape (viewed side on looks like and ellipse) the planshape then rotated around the nose to tail centre line viewed side on reveals a related deck and rocker, made by blending the plan shape with the ellipse. So my situation at the moment is, I have sorted out the most efficient way to make boards with the modern 3D CAD and I am now using that to finalize a few designs and then start a website and cop an incredible amount of abuse from the non believers.

22 years of CAD design and cnc machines plus 13 years of surfboard geometry, with about 5 years of that 13 being fulltime at computer. And I intend to send guys all over the world AKU files for their requested boards so that they can have their local AKU guy cut it out. (for a price I hope). Some of them will rip me off but most will just be very happy.

I’m getting old, time is running out. Some portion of the world is waiting. Sorry no pics today, still not ready to show. And one day Stoneburner I will complete my ambition of turning your 2D ideas into 3D CAD files, just got to get this all started first.

Congratulations well done , I remember several years ago following your posts with interest I understood what you were doing but not how you were doing it , hope it pays off for you .

Hey John, been wondering how your project has been going. Once you have your math-based design dialed in, you can build it anywhere in the world at any time. I look forward to seeing your results. Maybe you could protect your technology with copyrigths and licensing.

I have been playing with ellipse-based fin design. Most recently, I have begun designing channel bottoms by hybridizing ellipse-based curves with NACA profiles. It did not take long to see that CNC would be the most efficient and accurate way to shape the channels.

Good luck and keep us posted on your progress.

Damn malaroo. You sound (read) like a mad scientist. Literally. I mean no disrespect. I’m not sure I understand the goal. There is no magic formula, logarithm , for a perfect board because surfing is subjective. Can you explain your final goal? Did I miss something? What about the joy of using relatively simple tools, your hands, a power planer, block plane, sanding blocks, abrasives, etc and being covered in toxic dust. Build it. Surf it. Build it. Surf it. Learn. What am I missing? Mike

Not attempting to answer for Malaroo, but just observing. Malaroo has said nothing negative about handshaping with simple tools. He simply pursues his own vision of mathematical surfboard perfection, and has received stoked confirmation from talented surfers who have sampled the wares.

Physicists tell us that all the laws that govern the physical universe are based on math of the highest order, so it would come as no surprise to me that mathematical formulas, which we know govern the movement of waves (i.e. google “sinusoid”), might also hold the key to some optimal surfboard designs. None of which detracts from the fun that guys like me have building boards designed with pencil and sculpted by hand and eye.

I’m a surform handshaping old school hand drawn template backyarder, but I respect his dedication to his own personal vision, and in all his posting here he has come across to me as dedicated, humble, and devoid of the kind of chest thumping self-aggrandizing hyperbole and exaggeration that often accompany claims of scientific superiority for certain designs. In short, he is IMO the real deal, and I wish him all the best success in his pursuits.

[Quote=Rooster] Damn malaroo. You sound (read) like a mad scientist. Literally. I mean no disrespect.

Rooster! If it sounds and reads and looks like a mad scientist it probably is. I mean I probably am. LOL. Kind of a have a go wanna be type.

[Quote=Rooster]I’m not sure I understand the goal. There is no magic formula, logarithm , for a perfect board because surfing is subjective.

I have the same problem with logarithms maths formula’s, why would you bother? I design my boards with surface intersection on 3D CAD, so easy, create two shapes, put them through each other and the computer CAD will give you the line where they intersect.

Do that without a computer and I guess you call it geometry. There is a lot of maths and geometry behind the writing of a CAD program, But the user (me) doesn’t need to know any of that. I don’t know maths and geometry and logarithms. I certainly take measurements seriously, have to, but that’s about it.

So its a bit of a joke (but its true) when I say my boards are designed by geometry. Malaroo Surfboard Geometry. Sounds better and creates more interest than Malaroo Surfboard CAD Surface Intersection Designs. I hope your not too disappointed.

[Quote=Rooster] Can you explain your final goal? Did I miss something?

I think the advantage of the system I use is the fact that all the curves are related (Design Relativity … Hmmm that sounds good!), the curves are built from the same source, and each other, and therefore related.

And with my new range of boards the fins will be derived from the boards shape. The fact that they are designed with CAD (and therefore maths geometry logarithms whatever) and cut on CNC, the curves should be perfect curves.

I have had the best surfs of my life (that’s no big deal, I am not a great surfer) on my Malaroo boards, I believe (and there are many Malaroo enthusiasts that agree) that there is a magic that comes from the design concepts. (I have had a lifetime of surfing and ridden many different boards). The Malaroo’s are definitely a quality alternative. I actually can’t wait to ride my new range.

[Quote=Rooster]What about the joy of using relatively simple tools, your hands, a power planer, block plane, sanding blocks, abrasives, etc and being covered in toxic dust. Build it. Surf it. Build it. Surf it. Learn. What am I missing?

I don’t think there’s anything wrong with hand shaping, I’ve done a few in my lifetime, some recently, I am incredibly slow at making a board by hand, I love doing it, but I can’t make a living doing it.

There are guys here that I deeply admire that make faultless boards by hand. They are skilled at what they do and have spent a lifetime developing that skill. Pretty amazing. I’m sure you appreciate that as well. like a famous rock star … incredible what they do.

My life took a different direction, Got into CAD design and CNC machines through having a Guitar making business, (9 years, plenty of sanding and toxic dust to play with there) then designed some boards using the surface intersection method and it really took off, people asking me if they could ride my board and borrow one to show their friends then sales just took off, couldn’t deny the response. 207 sales, one design in the first 2 years.

At that time I also stuffed my right arm, it was out of action for 3 years, couldn’t surf stand up or sand boards. (or play guitar much or make guitars). My CNC machine saved me. I sanded as much as I could (usually final touch up stuff) but I had to pay others to do the sanding and glassing. It also showed me that I could build a business without being physically tied to the board, sanding and glassing. All I had to do was the CAD design and express my rules of good sanding and blending curves and respect the skills of the people I used to process the boards.

[Quote=Rooster]What am I missing?

by shaping riding learning developing, you are probably making boards so close to perfect that the difference is undetectable, I hope you are not missing the ability to realise how great and relevant to you they are.

When I get the Malaroo Surfboard geometry site up and going, if you really want to know if there is a difference I will gladly send you an AKU file of your choice, you can get some one local to cut it out (very cheap) and sand and glass it yourself, and that way, you wont die wondering. If you hate it, I would love to know why and take your comments as constructive criticism that might save me from making crap.

Thanks Rooster, great questions, representing many peoples concerns.
Goodnight guys I will reply to all who have posted.

Thanks gbzausa, really nice to know you found it interesting and understood the concept, great to know you felt compelled to say something. Thank you

Thanks Malaroo! Maybe I’ll order a board and report back. I was in no way trying to resurrect the old hand shape vs. computer debate my friends but admit a hand shape bias. I think you should build them any way you choose and be STOKED! Mike