View Full Version : Rockers and bottom shape guide

8th August 2007, 09:02 PM
How does this thing with rockers and bottom shape work ? What is it ?How do you "messure" it and how does it affect the board ?

Can someone please explain this to me ?


9th August 2007, 02:53 AM
Ouch, that's a question that would require many, many pages to answer and even then it would be a bit of a guess as everybody got their own twist on how these thing really work.

But the (very) short story is that the bottom of the board is kind of "bent" or curved. Place a ruler along the bottom of the board and you will see that it is not flat but has curvature along it. This curvature changes along the board and the front part (called the scoop) is generally curvier than the rear part. Extremely small changes in curvature along the planing surface of the board makes for huge changes in its behavior. To this rockerd bottom, the shsper can then add a vi shape, a concave, double concave and combinations of the above which then also is allowed to vary when you move along the length of the board. You can for example have a single concave in front, that becomes a double concave v in the middle and then turn into a flat bottom at the rear. Concaves and v adds their own flavors tot he feel of the board but at least as important is the fact that when v and concave change along the board, the rocker changes with it so the bottom _shape_ and its curve has to fit together to give you that really magic combination of good turning and good speed.

10th August 2007, 03:46 AM
Ok. I think you made a good general description of it. Now I see how it works.

But what about the edges of the board ? What does sharper edges do to a board etc ?

10th August 2007, 04:47 AM
from what I understand, a sharper edge creates a faster board because it sits higher in the water when planing (less board in the water = less friction). What a rounded rail does is it gives more maneuverability because the board sits lower in the water compared to a sharp rail when planing and its easier to roll into a turn with a rounded rail.

Does anyone know any websites that explain the science behind the windsurf board? I am very interested in learning what makes things work they way they do.