However, successive wraps increase the shear strength by a combination of the friction and compression-loading of the Velcro by overlying wraps. UV rays, use, and dirt or fibers in the contact area can reduce this by half. The strength of Velcro clew straps rely on having enough wraps so that the shear load on the wrap is less than the shear strength of the Velcro, which Practical Sailor testing has shown is 6 to 12 pounds per inch of 1-inch-wide strap of new material. There is no functional improvement in strength or stretch. Spectra webbing slides more easily on the boom, but if the loop part of the Velcro is against the boom, this is irrelevant. If the clew strap is too loose, particularly if the clew is within four inches of the end of the boom, the outhaul will carry much of the sheeting load and will become difficult to adjust. If the clew strap is too tight (actually difficult to accomplish) it can be difficult to slide. Consult a rigger or the owner of a sister ship to determine what works best. However, with mid-boom sheeting, the bending load on the boom will increase slightly, and attaching the clew to a rigid track may better distribute the load. With end-boom sheeting the added stress on the boom is minimal-nothing compared to vang loads. Plain webbing straps also slide better if you sew or stick self-adhesive loop Velcro to the bearing surface. With Velcro straps, the fuzzy loop side should bear on the boom, since it slides better. A lashing also slides better when it is covered with tubular webbing. If you use a buckle, consider covering it with tubular webbing to avoid scratching the mast. Lubricate the strap and the underside of the boom with a dry lubricant such as McLube Sailkote. Obviously, there can be no hardware on the sides or bottom of the boom within the sliding range. When the outhaul is eased, the clew automatically slides forward in all but the lightest airs. Flattening the sail requires only a firm pull and no purchase, and a winch is needed if there is wind in the sail. With a clew strap, the clew moves nearly as easily as a traveler car system. Flattening the sail required using a winch, even with no wind pressure, because the cloth had to be forcibly stretched. The original sail, with attached foot and sail slugs, often stuck in lighter winds, requiring pushing against the center of the sail foot to get the clew to slide in and the sail to increase in fullness. This wasn’t our first loose footed sail, but it was the first wed installed on a boat that was not factory equipped for this. In truth, that simple webbing strap would have lasted the life of the sail, but as dedicated tinkerers, we soon replaced it with an adjustable strap with a buckles, which has functioned well for five years.
When we rigged our new main on our test boat, the existing sail slugs didn’t make us happy, so we lashed the clew to the boom with a sail tie, wrapping it twice and securing with several half hitches. Sailmakers don’t always include this simple device with a new sail, since they don’t know what hardware you have or what your preferences may be. They became standard equipment on larger race boats as well, including Farr 40s and TP 52s.
Simple Velcro wraps first appeared on racing dinghies such as Lasers, where they provided a lightweight solution that adjusted smoothly, allowed for fast sail installation and removal, and eliminated complicated and heavy track systems. Unfortunately, the car or slugs are often undersized or prone to jamming without help from an attached foot. For most boats, switching to a loose footed sail is as simple as attaching the clew shackle to the existing final slider (reinforced slugs are made for this purpose) or car.
Velcro clew strap Patch#
In a loose footed sail, the clew patch is slightly enlarged to compensate. In fact, the sheet load will always be carried in a radial pattern originating from the clew, with most of the load carried by the clew ring. Most new mainsails are loose footed.Ī common misconception, or at least exaggeration, is that an attached foot provides better support for the sail. Both are used on both high performance and cruising boats. A sail with an attached foot, secured to the boom with a bolt rope or sail slugs, has a small advantage in area, while a loose footed sail is easier to adjust (flat for windward work and smooth seas, fuller for reaching and rough seas), slightly cheaper to fabricate, and much easier to take off the boom for storage. After settling on the material, one of the most basic mainsail design questions is whether to have an attached foot or loose-foot.
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