Seems like we’re in the mid summer slowdown here so I thought I’d start another build thread.
I wanted to make sure that all turned out well before I started posting. No sense in getting everybody going on a thread that either never gets completed, or screwed up on the way, so the board has been completed and ridden.
I’ve only had it out on some slow summer surf, but that was what it was designed for. Super glide, and turns good too.
I’ve got my own unusual way of drawing templates and rocker profiles. I’ve posted a little about it before.
Some get it, and others think I’m way off track and way too complicated. If it works for you, great. If you think I’m nuts, you’re not alone, and certainly not the first, so join the club.
In the picture, I’ve drawn three circles. The largest, then a smaller
one, tangent to the first. Then a third circle, tangent to the second, but at a different spot. I then drew an arc from the largest to the second to the third circle. This lets me draw a smooth arc with a known curve. No connecting the dots, or bending fishing rods or anything else to get a smooth transition.
Back to the arc drawing. I use this for both drawing templates and rocker profiles.
I do it easy on AUTOCad. But it can also be done with some masonite and a tape measure.
Go find some open room. Put a nail in the ground and hook your tape measure to the nail. Walk off a distance, set down your masonite. With your tape hooked on the nail, and the pencil against the tape measure, draw an arc on the masonite. That’s your first curve. It only needs to be a few feet long, maybe four feet long.
Repeat the last step with different lengths of tape. Do one about six feet from the nail. Another ten feet. Another twenty feet. The largest curve on this board was sixty-eight feet, and that was for the mid point bottom rocker. The more templates you make, the more flexible your designs will be later
Home Depot sells 100’ tapes for less than $20.00.
Cut out your new templates. These pure arcs will be combined later for your templates and rockers.
So back to the first picture, you can see how you can arrange the different arcs to create transitions.
The closer in size the arcs are to each other the smoother the transition will be. Also the closer the points of contact are to each other, the smoother the final line will be. I exagerated the first drawing. It would make a pretty bad surfboard, but it kind of shows my point.
For the rocker, the first arc was a sixty-eight foot radius.[img_assist|nid=1053559|title=rocker arc 1|desc=|link=none|align=left|width=569|height=457] I wanted the tail rocker to be two inches, the nose rocker to be four inches, and the main rocker to be really flat.
The second arc was for the tail rocker. That arc had a twenty-six foot radius[img_assist|nid=1053561|title=rocker arc 2|desc=|link=none|align=left|width=738|height=593]
The third arc gave it a little tail flip, and brought it up to the 2" tail rocker that I wanted.[img_assist|nid=1053562|title=rocker arc 3|desc=|link=none|align=left|width=625|height=502]
I used the same technique to draw the arcs of the template. Here are the dimensions. The first step is to figure where you want the wide point, and how wide the board should be. This one is 20 5/8" wide with the wide-point 2 7/8" behind the mid-point.
After the main arc is drawn, add in your second and third arcs and so on, to get the nose and tail outlines. It’s all about placing the arcs tangent to each other. The arcs shouldn’t cross each other or you’ll get a bump in the outline. They should just kiss up to each other.[img_assist|nid=1053564|title=6-9 stringerless template|desc=|link=none|align=left|width=674|height=541]
So you draw a single arc using the tree circles as a guideline (not three sections pieced together)?
In BoardCAD you have the curvature radius as a visible parameter when editing the curves allowing you do pretty much the same thing only without drawing the guides.
Even though the circles tangent, there will be a break in the curvature ie. the outline will go from a 5 yards radius to a 3 foot radius abruptly. Atleast in extreme cases this will be visible.
Same goes for bezier curves used in surfboard cad software. Even at a knot where the vectors tangent, there still might be a break in the curvature. That’s why SurfCAD, Shape3D and BoardCAD show the curvature so you can make curves that have a higher level of smoothness(C2 vs. C1 if I remember correctly).