We are about to order a new set of sails from Ullman for Revelations - mainsail, genoa and spinnaker. Considering all the available materials is complicated and complex - with no easy right or wrong answers, nor a "perfect" solution. For blue water cruising, sails simply have to last – it is false economy using a cheaper product if it fails mid ocean. Most of us have sailed with a spinnaker or cruising chute at some time and you may remember the sail is flying unsupported from the spars, hence occasionally the sail will fill and collapse. Often this can be be with quite a 'pop' and for this reason we want the sail to absorb some of that 'shock' and so we choose a slightly forgiving fabric.
We usually choose Nylon as it has a little more elasticity as a fibre and it's usually woven in a form these days that we call Ripstop. Which means it has a square weave pattern that is formed by periodically twisting a few fibre together to increase tear strength, or occasionally by added a larger fibre into the weave at even spaces.
So, Nylon downwind sail fabric is very light, a little stretchy and surprisingly strong. The fabric weight is usually expressed firstly within a generic weight category - such as '3/4 ounce', or '1 1/2 ounce' and then as a style name with a more detailed weight that may well now be in grams.
Most importantly these materials are available in attractive colours so you can personalise your sail and keep the crew entertained! Either of the weight categories will 'fly' in quite light winds even as smaller sails - but often the heavier wind range sails (or more all purpose sails) will be in the 1 1/2 ounce weight range. Because the lightest material comes at the expensive of some durability and tear resistance if the sail handling isn't quite as slick as you had planned for!
In cruising sails usually 3/4 ounce is good for light symmetrical shaped spinnakers and 1 1/2 ounce is best for heavy symmetrical shaped spinnakers, asymmetric and cruising chutes. There are also heavier weights of downwind sail fabrics for bigger yachts and for racing sails there are lighter ones ... some are more heavily coated with a stabilising resin to make a harder 'crispier' feel and support that unsupported flying sail shape.
Upwind sail fabrics are more complex and since there are more variations in weight and factors of construction to consider. The absolutely most robust and longest lasting sailcloth available in the world is Dimension-Polyant ‘Hydra-Net’. If the boat is going to be extensively cruised, particularly long offshore or in adverse conditions we recommend a style of material called Hydra-net. This material is a woven mix of Polyester and Spectra producing the most rugged and reliable sailcloth available. This material is very low stretch and provides ultimate reliability; ‘Hydra-net’ therefore provides the most rugged long lasting Blue Water sail cloth available on the market. ‘Hydra-net’ is also the softest fabric option available and is therefore the easiest to handle; this is relevant whether the sails are for roller reefing or folded into Lazy Jack systems. All other materials will be quite firm and therefore bulkier than your existing older sails and would be harder to fold away, however ‘Hydra net’ is soft and pliable and easily rolled and folded, this means that ‘Hydra-net’ is ideally suited for short-handed cruising. The final advantage of ‘Hydra net’ is that it has excellent UV resistant properties. Hydra-net is the fabric of choice for blue water cruising yachts. The ‘Hydra-net’ fabric comes in two different styles, one suitable for cross cut sails and the other for radial constructed sails. The cross cut version is fairly balanced with Spectra/Dyneema running in both directions. This fabric is the absolutely most robust and softest/easiest to fold/roll fabric available on the market, for a Blue water cruising boat or an aging family crew where soft and easy to handle sails are desired then the cross cut version of ‘Hydra Net’ is absolutely perfect. This material also has a unique to Dimension-Polyant a UVi coating in the resin that helps to protect the sail from harmful UV exposure and can increase the materials lifespan by around 15%The fabric performs better than most woven Dacron but is stretchier and therefore inferior in shape retention when compared to laminates or the radial version. The stretch that does occur is fairly elastic so any elongation that does occur is not permanent, but it does mean that although a high quality product this material is aimed at ease of handling rather than performance.
‘Hydra-net Radial’ has far more Dyneema running along the warp and offers far superior shape retention and therefore performance, yet the fabric is almost as soft and easy to handle as the cross cut version. ‘Hydra-net Radial’ out performs all other woven materials including ‘Vectran’ and most laminates. For a blue water cruising yacht where performance and shape retention is desired ‘Hydra-net Radial’ is the perfect material. The radial version is far better suited for high aspect sails and this is the style we have quoted for This material also has a unique to Dimension-Polyant a UVi coating in the resin that helps to protect the sail from harmful UV exposure and can increase the materials lifespan by around 15%.