Template radii


Just something to throw out here.  My next board's template.  A series of arcs with radii of graduating lengths.  The numbers are a little hard to read.


  • 3'-10 3/4"
  • 7'-5 3/4"
  • 13'-4 1/16"
  • 6'-1 1/2"
  • 1'-5 15/16"








As long as the arcs don’t cross when you draw them out. no bumps, flat spots or wiggles.

what program are you usingfor this Mark?


If you have something in mind, give me your rough design, and I can run it through.

Thanks Mark, I appreciate it!

I’ll get back to you today.

Gotta measure my blank and see how much room i have.

p.m. me with your e-mail.

I can print it out to PDF and send it to you.  Then a trip to kinkos and they can print you a full size paper template.  No pasting 8 1/2 x 11 together.

Hey Everysurfer, check your PM’s

With circles, you can get the first derivative continuous like you did, this means that there are no angles.

But you can never get the second derivative continuous, wich means that there are bumps! But you managed to keep them invisible to the eye.

I’m not saying the design is not good, it probably is great.

But saying you have no bumps is mathematically incorrect.

but if you’re hand shaping, doesn’t the math dissolve into the finished template? Even if a CNC router did this verbatim to the drawing, the glass job will dissolve all these minute mathematical bumps anyway?

I just got Alias and am learning nurbs, contouring. Some of the stuff I draw digitally I know I can get really close by hand…

Hey Chris,

Check your e-mail.


Yes Hans, mathematically there are little bumps.

Vaeske, When you shape, you can smooth out a lot of flaws and wiggles.  This just gives you the perfect template to start from.  Also it gives you numbers that you can re-use on future designs.


Also the template below took me about a half hour to draw up.  Much faster than a lot of other methods.



Sure, and it even could be that the bumps are smaller than your shaping accuracy.

I just wanted to correct the statement that there would be no bumps when circles are pasted together.

So no comment on the shape or anything that will probably all work fine!

In the end it just comes down to find the parameters and guides that work for you.

I know quite a lot about mathematics and numerical modelling/simulation, but I found that for shaping the old techniques work best for me.

I try to work with a limited set of parameters and I create my curves by bending wooden sticks.

Only for building fins I really rely on calculations.

But that’s just me, it’s all about finding your own way. This circle technique is certainly a valid one!

And it isn’t like you need a computer to do this.  Just make some masonite templates.  2’ radius, 4’ radius, 6’ radius 8’ radius. and maybe a 10’ radius.  Each mini template only needs to be a couple of feet long.  From there you can mix them up to draw anything. 

That can be very handy indeed!

Then you don’t need to keep and build so many templates.


true that…running out of template room mylself. Might just start chopping my special tails and adopt this method. Great ideas as usual, Mark.

I have a stack of arks ranging from radius of 8 up to 42ft.

Things start to get more 

Interesting for me with parabolics and oval templates.



Kayu, do you mean, flip templates? Not sure I follow what a spin template is…

Individual flip templates are what I have now, and this arc idea is something appealing…mainly because if I can draw outlines just as efficiently, why would I need individual flip plates?

**Arcs, ovals, ellipses, nurbs, and unique tails. **Free up more wall space, less time shaping masonite, more time shaping foam.

…or you could make spin templates with no bumps…not trying to be negative Mark , but which is more efficient ?


42!? Boat building? What material is your template when you exceed 8 ft?


I think you don’t understand exactly

My templates range between 3 and 6 yards.

The radius of the ark (circles) are between 8 and 42 ft.

42 being a flatter curve, for the middle section of a fun board etc.

Not bloody 42ft long, thats just retarted…

got it, ok…so an 18 ft template being your largest. For a 6 yard template, Is there another material a bit more durable than tempered hardboard? -like thin polycarbonate?

I’m sold. Rethinking the template archive…