high and low aspect properties: all in one sailcloth
NAUTOSPHERE VOYAGER™ has both high and low aspect properties. Not as a compromize between these properties. Rather, both properties are optimized in one sailcloth.
This feature is better explained with a few examples. Take as an example a low aspect Dacron construction, weighing around 400g/m2. This could be made from a 420 dtex warp and a 750 dtex weft. Assume we want to improve the high-aspect properties of this sailcloth. Considering that polyester is a fairly low modulus fibre, we would have to replace all the weft fibres with, for example, a 1000 dtex yarn. To maintain the weight around 400g/m2 we would also have to reduce the warp to, say, a 330 dtex yarn. By doing this, we will have reduced the strength of the warp yarns and, in addition, increased the warp crimp since the warp fibres now crimp around heavier weft fibres. As can easily be seen, we will have weakened the warp and lost the low aspect properties in pursuit of high aspect properties.
This explains why Dacrons are available in both high and low aspect versions. Dacrons can be optimized in regard to one property only at the expense of the other, due to the relatively low modulus of polyester. Therefore, sailmakers have to choose which property is more important. In a Dacron, they can't have both.
Assume instead that we introduce Dyneema in the weft. To achieve a very significant improvement in high aspect properties we only have to replace 1 out of 4 weft yarns with, for example, a 1750 dtex Dyneema fibre. These Dyneema fibres, provided they are completely free of any crimp, can easily carry the weft loads on their own, creating a much higher resistance to stretching than a full weft of 1000 dtex polyester. This, in turn, allows us to disregard the intermediate weft yarns (the 3 out of 4) for high aspect properties. These can now be substituted with finer yarns, for example a 550 dtex. The outcome is that we maintain a weight of 400 g/m2 without making any change to the warp yarns and without introducing any more warp crimp.The high aspect properties of this sailcloth is now improved considerably with no sacrifice of low aspect properties.
We can take this principle a step further. If we rely on the Dyneema fibres for high aspect properties, and reduce the intermediate weft yarns even further, to for example a 330 dtex, then we have room to even improve the warp and still stay within our weight constraint. The 420 dtex warp yarn can now be replaced with a 550 dtex polyester, a warp yarn that would normally be used for a heavier sailcloth. The result of this substitution is a stronger warp, as well as less warp crimp due to even finer weft yarns.
In other words, both high and low aspect properties have been improved. This example illustrates how Dyneema fibre in the weft of a sailcloth can improve not just the weft itself, but also the warp.