Actually even a perfectly flat (hard board) panel can work as a sail, the only difference being that it is less efficient then a shaped sail. So that criterium, being able to work as a sail, is not very useful.


Also, the shape of the panel (however you define that) is absolutely vital in determining the final shape of the finished product. How can I show this to you without having to use more arguing ?

This might work !

Think of the similarities between 3D sailmaking and the tortured ply method of building hulls. Of course the latter is also know as "stitch and glue building" but that is a sidetrack. Go to this link to see the 3D mould and the panel shapes :

http://www.catsailor.com/forums/sho...er=132859&Main=132040#Post132859

Note the similarities between 3D sailmaking using a 3D mould and the creation of these F12 hulls using again a 3D mould. Actually in principle there is no difference.

Now there are two mind experiments for you :

-1- You try to get flat panels to sit right in that mould without shaping the edges of the panels.

-2- You try to flatten any combination of two or more shaped panels that have been joined and taken from the mould.


You can't do the first without significantly curved egdes (broad seaming)

You can't do the second without rupturing or even totally distroying the connection at the seams.

The mould is only there to keep the panels properly curved and positioned relative to eachtother to allow the bonding (seams) to be created. After the bond has set (is finished) the mould can be taken away and the the internal material forces around the seams will maintain the overall 3D shape.

With regular sailmaking the sections are just pinned (or glued) together at the seam and bundled up while being moved under the sewing machine, much like our mothers did with our clothing ! With 3D sail making the sections are pinned over a 3D mould while being glued into place. That is not enough to qualify as a fundamental difference (between 3D and regular sailmaking).



This is the way things are when making 3D shapes from any 2D "ingredients"; as all sailmakers do because the cloth and monofilm suppliers all produce flat sheets/films; possibly bend over rolls or folded up for easy transportation.

The only way out of this stranglehold is 3D polymerisation (similar to casting metals) OR reshaping the panels by heating them and resetting the material structure to a new overall shape (similar to forging metals).

The first implies that the material is directly created chemcially in a 3D mould of the sail. As of yet there are no such machines and it is extremely unlikely that such a machine will ever be build for a sailboat sail (notice the singular as any you will need a new machine for every new sail design). Of course such machines are created for some mass produced elements like automobile parts and electrical wall outlets.

The second method has the problem of not being fundamentally different for thin sheets; look at it this way. Forging a thin sheet of material to a reflect a different contour is no different then simply cutting the resulting contour from an unforged piece of thin sheet. Different paths, yet the same final results. Of course forging pastics runs into several other problems that make it much less attractive then it is for metals. A very large portion of plastics don't take well to heating for example.

Wouter