Radial Sails

While cross-cut sails were built from woven Dacron, laminated fabrics allowed sailmakers to build both cross-cut and radial sails depending on how the fabric was engineered. When the fabrics were laminated the scrims were laid so that the strength in the fabric could run in the warp direction, the fill direction or both. Fill-oriented laminates were still used to build cross-cut sails, while warp-oriented laminates were used to build radial sails, i.e., sails in which the panels were not just stacked up parallel to the foot. Sailmakers had been building tri-radial

Figure 4.10

Warp-oriented laminates were used to build radial sails, i.e., sails in which the panels were oriented along the load lines, not just stacked up parallel to the foot.

Radial sails are common on the race course where fabric efficiency is key to saving weight and minimizing stretch.

Radial sails are common on the race course where fabric efficiency is key to saving weight and minimizing stretch.

RADIALL HEADSAIL

Panels rvdivte from the corners tu handle the loads better

Heavier fabric is used u|L the leech.

spinnakers for some time so the concept of orienting the panels along the load lines was not new (Figure 4.10). It was just that this was the first time they could build working sails with a tri-radial panel configuration.

One of the principal benefits of radial sails is that the sail designer can engineer sails with different fabrics in different areas of the sail to address specific loads. In other words, heavier fabrics can be used along the leech of the sail or at the head and clew where loads are highest, while lighter fabrics can be used in lower load areas like along the luff. These fabrics can differ in terms of overall weight and specific lay-up. They can also differ in terms of the types of fibers and yarns used to carry the load. For example, the sailmaker can design the sail with low-stretch Kevlar yarns in the high-load areas and a regular polyester in the rest of the sail. In doing so, he can keep the cost of the sail to a minimum while still gaining the maximum benefit from the exotic fibers. If the sail is going to be used on a race course, the sailmaker can add durable, chafe-resistant panels through the foot area to take the abuse handed out each time the boat tacks. If the sail is going to be used for long cruising passages, similar patches can be used in other high-chafe areas, for example, where a mainsail rubs against shrouds or spreaders. The same can be done for woven cross-cut sails but the patches are added on later. Incorporating them in the original design is a more efficient way to build a sail.

Of course, sails are used not only for sailing upwind, but on reaches and runs as well. Mainsails in particular have to able to perform on every point of sail. Some boats, like those that compete in Olympic events, the America's Cup, or other inshore events, spend most of their time sailing either hard on the wind, or sailing deep off the wind, while others, like those that compete in long-distance offshore events spend much of their time reaching and running. Much like head-sails, when sailing hard on the wind the principal loads on a mainsail go directly from the mainsheet onto the clew of the sail and then straight up the leech. As soon as you bear away, however, the loads are decreased and extend further into the body of sail, creating a whole new engineering problem.

In the case of racing sails used on an upwind/downwind course, for example, the sailmaker may choose to build a bi-radial main (Figure 4.11) with load-bearing gores radiating out of the head and clew only - bi-radial meaning that there are only two sets of panels radiating out from the corners, i.e., the head and clew. Although the body and tack of the sail will be subjected to somewhat higher loads on the

Was this article helpful?

0 0
Boating Secrets Uncovered

Boating Secrets Uncovered

If you're wanting to learn about boating. Then this may be the most important letter you'll ever read! You Are Going To Get An In-Depth Look At One Of The Most Remarkable Boating Guides There Is Available On The Market Today. It doesn't matter if you are just for the first time looking into going boating, this boating guide will get you on the right track to a fun filled experience.

Get My Free Ebook


Post a comment