Re: Qsails
Bill Kinney
Dennis,
Loads on a cross cut sail are very different than those on a radial cut. The weave of the fabric needs to be matched to the loads. Fabrics made for cross cut sails can not be well used for radial cut sails, and vise versa.
I would disagree that cross cut sails are intrinsically better for roller furling mainsails. You can make an argument that the cross cut construction is better when the sail is new, but all other things being equal, a radial sail WILL stretch less than a cross cut sail. A stretched and baggy sail is miserable to roll up inside a mast and will cause all kinds of grief. For the typical cruiser who is looking to make sails last as long as possible, good radial cut sails will last longer in roller furling applications.
The primary downside of a radial sail is the cost of construction. There are a LOT more seams that need to be pushed through a sewing machine and that costs money. Typically, a cross cut sail can be "triple stitched" with each seam sewn three times. While it might be theoretically POSSIBLE to triple stitch a radial cut sail, I have never seen such a beast. Since loadings in a radial cut sail are parallel to the seams this is not really a strength issue, but it means that any chafe on stitching needs to be attended to quickly since there are no back-up stitches nearby. In a cross cut sail, much of the load is ACROSS the seams and the extra stitching is really not optional for full strength.
Battens cause endless arguments. For standard hoisted sails, battens are a useful compromise. Certainly more wear and maintenance, but better performance. I had them on my old boat, and would not change that. On a roller furling main (or mizzen) I avoid battens. The benefits (in my opinion) do not out-way the drawbacks. At least on a Super Maramu the mainsail is a minor player in driving the boat. Any improvement to the mains's performance would have to be REALLY dramatic to have much of an effect on the overall performance of the boat.
Bill Kinney
SM160, Harmonie
Hollywood, FL
Loads on a cross cut sail are very different than those on a radial cut. The weave of the fabric needs to be matched to the loads. Fabrics made for cross cut sails can not be well used for radial cut sails, and vise versa.
I would disagree that cross cut sails are intrinsically better for roller furling mainsails. You can make an argument that the cross cut construction is better when the sail is new, but all other things being equal, a radial sail WILL stretch less than a cross cut sail. A stretched and baggy sail is miserable to roll up inside a mast and will cause all kinds of grief. For the typical cruiser who is looking to make sails last as long as possible, good radial cut sails will last longer in roller furling applications.
The primary downside of a radial sail is the cost of construction. There are a LOT more seams that need to be pushed through a sewing machine and that costs money. Typically, a cross cut sail can be "triple stitched" with each seam sewn three times. While it might be theoretically POSSIBLE to triple stitch a radial cut sail, I have never seen such a beast. Since loadings in a radial cut sail are parallel to the seams this is not really a strength issue, but it means that any chafe on stitching needs to be attended to quickly since there are no back-up stitches nearby. In a cross cut sail, much of the load is ACROSS the seams and the extra stitching is really not optional for full strength.
Battens cause endless arguments. For standard hoisted sails, battens are a useful compromise. Certainly more wear and maintenance, but better performance. I had them on my old boat, and would not change that. On a roller furling main (or mizzen) I avoid battens. The benefits (in my opinion) do not out-way the drawbacks. At least on a Super Maramu the mainsail is a minor player in driving the boat. Any improvement to the mains's performance would have to be REALLY dramatic to have much of an effect on the overall performance of the boat.
Bill Kinney
SM160, Harmonie
Hollywood, FL