Panelled Sails

[Bill Roberts]

Hey Guys,
On Catsailor there is a thread about the Tornado class and some sailors at today's Olympics have shown up with "panelled" or cross cut sails rather than tri radial or vertical cut sails. These new panelled sail cuts are thought to be faster than the old tri radial cuts. Also new materials are required with the strength aligned across the panel rather than lengthwise along the panel. Check with David Ladurini about this breakthrough idea.
Did youall know that Supercat factory sails have never been tri radial cut?
Tri radial cut sails came into popularity about 20 years ago because you could do more with colors, make many different colorful patterns. Cross cut sails are superior in sail shape control and they are much smoother, cleaner to the wind. The seams on a cross cut sail are parallel to the airflow across the sail and there are fewer seams in a cross cut sail and the seams are shorter in a cross cut sail. The cross cut sail has every advantage except you can't do as much with colors and patterns as you can in a vertical or tri radial cut sail. If you want to go fast, go cross cut. If you want to look colorful, go tri radial.
Bill

[Mike]

OK come on now Bill, didnt the tri radial design have something to do with load pattern dispersion, strenght characteristics,aligning the strenthg of the material with the load pattern and all that? Sounds like your throwing some big old challenges out there to see if anyone is listening?? No disagreement as to what is better/faster/more efficient ....just the real reason as to why the 'racing" classes went to tri-radial designs while the local sailmaker kept the same software as what works on keel boats????Ouch what a dig !!!!

Take care, just letting you know we watch some of these posts. And no you dont need to change platforms.....the 27 is looking better and better every day. Now dont you go and automatically give me line honors! haha

Wouter.....just kidding Bill.
Mike Kelley

[Bill Roberts]

Hi Wouter, I mean Mike,
In the beginning of the vertical cut sail trend, there were many iterrations between sail cut, sailcloth construction, the use of computers to design sails and computer software. "The change, the new style," to the vertical cut sail got so much attention that sailcloth manufacturers began making cloth for vertical cut sails only. This forced some sailmakers to go with the vertical cut wave wheather they wanted to or not. The new fibers and colors were only available in the materials woven for "vertical cut". The only material available for cross cut sails was plain vanilla dacron.
The orientation of fibers to best carry the loads has been going on since sail making began. Rotating the sail panels so that the cross threads are parallel to the leech has been going on since the cotton sail days. The vertical cut sail is the "extreme" example of orienting the fibers with the loads. The vertical cut sail involves much more cutting of panels, much more glueing, much more sewing and in general much more LABOR and much more wasted material results. In most businesses changing production to a scheme that requires more labor and produces more waste is a step backwards. But, the sailors wanted the colors and the patterns and so that is what they got at a much higher price.
Above is a bit of sail making history from Bill's point of view.
Bill