I used to shape myself all my boards, using electric planners. A few time ago I was introduced to boardcad and started trying, bought a few blanks and sent to a company to cut it. There are many variables that you need to change, but one is making me crazy.
The question is: For a modern performance short board, Wide Point, Thicker Point and Center o Mass must be in the same place, litlle behind the board center?
When you shape using planners is just you, your eyes and rulers, but using computeres requires more!
It naturally follows that wide point and thick point would coincide (doesnt have to, i know, but there is a certain logic to it), but center of mass, I don’t know. Because of the pulled in nose on a modern shortboard. I think center of mass might be a bit further back. I don’t design with computers, just responding to your post.
There have been a few threads related to this. I did a search with the keyword string “wide point and foil apex (or rocker apex) .” This is one I remember:
I keep centre of mass reasonably centred. If you have Shape3D, then you can see the distribution of mass and this is more useful than a single dot. I skew the CoM distribution forward a bit to allow for a heavy front foot style or kneeboard. I would pull it more symmetrical for a normal surfer.
I don’t think you should go crazy over the CoM location. It’s not a plane. The board isn’t really massive; you’re not fighting the effects of mass on a shortboard. The nose is light, and it’s short so the torque/moment isn’t an issue. You’re not trying to balance anything. You’re on the board, so you’re gonna force it into the proper orientation regardless of where the CoM is. Tape lead to your tail and you’re gonna ride front foot heavy to stop the board from pushing water on the tail rocker the entire time (disreagarding the drag incurred by a lead block on your tail of course, and assuming a normal board shape and rocker). Plus once you’re on the board the overall CoM is probably hardly different than your CoM (you without the board), since the board is a fraction of your weight. Different with longboards, of course.
To me it seems logical that it’s near the middle, or such that it’s somewhere near where you stand to create optimum planing, but it doesn’t seem terribly important. Volume distribution seems more important. CoM may very well be a function of that, but a seondary concern if you ask me. It seems like more of a secondary effect of length, width, area, volume and all those important things. It’d be silly to have a ton of mass elsewhere then have to surf the board funny cause it wants to tip one way. But having enough mass (concentrated to shift CoM that much) to cause that issue to begin with would be even more silly.
That being said, all my boards have the CoM further back. All my shortboards are wide point back. They have more tail area than nose, fins and boxes at the back (of course) and a traction pad. So the CoM is back there a bit, unsurprisingly. Wide point corresponds with the thickest point. I don’t have any particular reason for that other than that it seems logical, and those before me have done so (for the most part). I’m more interested in the volume distro curve than the CoM.
I just do my outlines in boardcad though. Sometimes I try to get the other parameters right to look at other stats, but I’ve never gone crazy over it.
Thank you for the comments, It helped a lot and at the same time more questions appeared.
And what about the Rocker`sZero Apex as Mr. Stoneburner commented above?
Below I attached a project ad comments about it, What do you think? The Center of Mass moves when you advance the deck and the bottom`s zero apex, should they be in the center or closest to the wide point?