Spinnaker Handling Techniques for Racers
As noted above, for the cruiser it is better to err on the safe and steady side when playing with spinnakers rather than take chances. But for racing sailors it's a different game. They expect to have occasional problems, and the trade-off between a quick spinnaker set and one that might possibly go wrong is a worthwhile risk. In this section we will look at four maneuvers in detail A bear-away set with a conventional symmetrical spinnaker. A jibe-set and a regular jibe with a symmetrical...
A Hypothetical Look at Buying Sails
It was not so many years ago that buying a new sail for your boat meant a pleasant trip down to your local sailmaker. You made a call e-mail was not yet invented , set up an appointment, and then spent a few wonderful hours looking at bolts of cloth, talking boats, and settling on a price. If you were a good customer a handshake would seal the deal, the sail would be made, and a few weeks later it was delivered to your boat an invoice would arrive by mail. Your sailmaker knew you by name - both...
Daisy Staysail
There is one sail that I am particularly fond of, a sail that is often found on racing boats, but hardly ever carried by cruisers, a sail with three names and a number of purposes. To some it's known as a Daisy Staysail. To others it's a Tall Boy while others simply call it a Windseeker Figure 10.2 . Regardless of the name, it is a high-aspect, loose-luffed sail usually made from a light fabric. Cruising sailors pre- fer the sail to be made from nylon, while racers will opt for a light...
The Design ProcessTurning Theory and Fabric Into Flying Shapes
Each sail goes through a number of design steps before construction can begin. Some steps, like sail geometry or the basic shape of the sails, are reasonably simple while others, like computing stress strain pictorials, require much more thought and deliberation. Ultimately, the shape of each sail will be drawn from a database of known sail designs and manipulated until the designer is satisfied that the sail he is creating for your boat is perfect for your purposes. Before we look at the...
Installing Telltales
It is very easy to add telltales to you sails. Follow the procedure below for installing both wool and light nylon telltales. Thread a needle with wool and poke it through the sail. Pull the wool through the hole until roughly six or seven inches remains. Cut the wool leaving a further six or seven inches on the other side. Tie two overhand knots on either side of the sail right up against the fabric. This will stop the telltale from pulling through. If you want to stagger the heights then...
Streamlines
Let's go back to the front of the sail again. Before any circulation was created you had a circumstance as shown in Figure 15.14. We now need to label some parts of this diagram, and I have done so using the terminology created by the scientists. The lines of wind flowing across the sail are known as streamlines. Between the flowing streamlines are two stagnation streamlines, i.e., streamlines that end or begin abruptly. These are created by the vacuum that arises when the flowing streamlines...
Biradial Mainsail
Panels ra nid clew be used f dcwnwini A bi-radial main with load-bearing gores radiating out of the head and clew only - bi-radial meaning that there are only two sets of panels Sails have become far more sophisticated than a simple tri-radial configuration. Here the panels change direction along the load lines in the sail. downwind leg, as soon as the racing sailor reaches the windward mark and bears away, the loads on the sail immediately decrease so that even though the loads may be...
The Spinnaker Turtle
Yarns, rubber bands, the spinnaker sock, and dousing sock are devices generally used on larger boats, say 30 feet and longer. On smaller boats it's not necessary to go to all this trouble because the spinnakers are much easier to manage. That's not to say you should not be careful, but you most certainly do not need to stop the spinnaker on a Hunter 26. Instead you should launch it from a spinnaker turtle, basically a round bag with a plastic hoop at the opening and a cover that has a bungee...
Case StudyTransatlantic Race
Two sailors are planning to compete in the Cape Town to Rio Race aboard different boats one a 60-foot IMS design with a reasonable budget and a strong will to win the other a 60-foot performance cruising boat that is planning to continue on after the race and sail to the Caribbean. The owner of the cruising boat wants his sails to be good for the race as well as for cruising afterward. For the owner of 60-foot IMS boat there are a number of options Low stretch - use the latest technology....
The Slot Effect
The mainsail also creates somewhat of a slot effect at the very end of the head-sail where the air is squeezed between the leech and the lee of the main. This is not the large slot effect that earlier studies pointed to because the circulation around both sails negates each other to some degree. But the wind does still speed up as much as 30 percent. In fact, studies have shown that the air coming off both sides of the headsail has an increased velocity and the Kutta Condition is met not at the...
Factors That Affect the Price of Dacron Sailcloth
In order to provide a yardstick by which fabrics can be compared, fabric makers rate the performance of different sailcloths by dividing the modulus of a fabric by its weight to determine a number called the specific modulus. In most cases fabric makers are striving for a high modulus low weight fabric, in which case they might incorporate some exotic yarns into a fabric to give it more strength. On the other hand, there are some occasions where durability needs outweigh performance, and in...
What is Cuben Fiber
You may recall from the introduction to this book, that the sails for the mega-catamaran Team Adventure were made from a revolutionary new sailcloth called Cuben Fiber, which we chose after weeks of rigorous testing of a number of different types of fibers and fabric engineering techniques. Some of this testing was The thing that sets Cuben Fiber apart is the way in which these raw fibers are turned into sailcloth. Once they are laid down the entire matrix is inserted into an autoclave . . ....
Dousing the Spinnaker
Now that you have the sail set and all is right with the world, you need to consider how to get it down. There are a number of simple methods and we're going to look at the asymmetrical first because it's the easiest to douse. Bear in mind, however, that no matter what spinnaker you are flying, your mainsail is your best friend, since as was the case with the hoist, it can reduce the force of the wind on the sail when it comes time to douse. In fact, the lee it provides is invaluable. It's true...
Tips for Using a Dousing Sock
When using the control lines to lower the hoop over the sail, lead them through a ratchet block mounted on the rail at a point forward of the boom and to leeward since this will allow you a measure of control over the lines, and you will be pulling up from the turning block on the deck rather than down on the sock. This way your feet will be squarely on the deck and you will not be dangling at the end of the sock hoping that the sail does not accidentally fill and flip you over the lifelines....
The Flattening Reef
This reef is found only on cross-cut sails and is located a short distance up the leech from the clew. When cross-cut sails are designed they have a very important seam originating just above the tack of the sail called a tack seam that runs perpendicular to the leech and plays an important role in adding shape to the sail by feeding a large amount of sail shape into the body of the sail. Once you take up on the flattening reef by winding up on the reef line, it cinches the leech and...
An Effort to Improve Dacron
Despite the fabric engineers' best intentions, for example, after a while all those fillers and finishes added to woven sailcloth begin to break down, and what starts off as crisp, low-stretch fabric becomes a softer, more easily manipulated sailcloth that begins to stretch and distort the sail shape. Therefore alternative means of creating a tight weave were sought. In the late '70s and early '80s Hood Sails believed it had solved the problem by producing its fabric in 24-inch-wide panels,...
The Dousing Sock
This invention has done for the cruising spinnaker what roller-furling did for cruising headsails, i.e., made the sail more manageable and less intimidating Figure 12.3 . The dousing sock is similar to the spinnaker sock except that it does not have a zipper. Instead, the sock is pulled down over the sail with a rigid fiberglass hoop that collapses the spinnaker and feeds it into the sock. The hoop has flared edges, and when a takedown line is pulled it gathers the spinnaker fabric and the sock...
Mitre and CrossCut Sails
Before we look at some of the latest sail designs, it's once again important to look to the past. As was the case with sail fabrics and yarns, if we understand how we got to where we are today, we will have some idea of where we might be going. Sail engineering is all about making good use of raw materials, both raw fibers and sailcloth. Back in the days of square-riggers and trading schooners all sails were made in much the same way, i.e., with their panels laid parallel to the leech of the...
Luff curve to be no move than oercent more than mast prebend
inboard end. If the roll size is uniform, the sail can roll up evenly and not travel forward or aft as you reef. If you have ever tried to roll up a carpet, you will know what I mean. The top ply added to the leech can also be a UV-resistant fabric to protect the sail once it is furled away in the boom. It works the same way as the UV cover on your rollerfurling headsail. Another important part of the sail is the luff tape, or bolt rope. In fact, the boom maker will usually supply a bolt rope...
Case StudyFabric for High Latitude Sailing
I recently had two customers who were building boats for high latitude sailing. One was building an 80-foot sloop and the other a 50-foot sloop. It's interesting that both customers had firm views on what they wanted, and both went against conventional wisdom with their choices. Since both boats would be sailing in areas where the conditions were harsh and repair facilities nonexistent, rugged and durable were the principal requirements. Both owners were presented with similar fabric choices,...
Afterguy
In some parts of the world the afterguy, or guy is called the brace. This line runs from the cockpit on the windward side through the jaw at the end of the spinnaker pole and attaches to the clew of the spinnaker. The afterguy is used to rotate the spinnaker around to windward, and in conjunction with the sheet can be used to flatten the chord of the sail. On larger boats a lazy sheet is attached to the clew as well, but since the afterguy is doing the work, the windward sheet lies slack until...
Fulllength Battens
Full-length batten mainsails have all the battens running from luff to leech. when it comes to battens they will extend the life of your sail since battens add support to the fabric and dampen the flogging that is one of the principal causes of fabric degradation. Full-length battens also assist in keeping the shape of the sail looking good after years of service, whereas with conventional battens wrinkles start to appear at the inboard end of the batten pockets after heavy use. Mainsails that...
Offshore Cruisers Inventory
With no plans to race, the offshore cruiser might have a sail inventory that looks like this Mainsail with two rows of reefs - each reef reducing the sail area by 20 to 25 percent. 135-percent roller-reefing headsail. 95-percent roller-reefing headsail. Working staysail heavy-weather jib. All-purpose spinnaker asymmetrical . See page 264 in Appendix for a definition of LP.
Swing Battens
In 2000 Doyle Sailmakers came up with an interesting new technology, which they patented. It's called a Swing Batten, and it's just that a batten that swings from horizontal when the sail is flying to vertical when you want to roll the sail A Swing Batten is just that a batten that swings from horizontal when the sail is flying to vertical when you want to roll the sail away. away Figure 7.5 . This batten is hinged at the outboard end and is controlled by a continuous line attached to the...
To drop the sail
Ensure that the pole guy is fixed in place. The pole guy holds the spinnaker pole in place. The trip line opens the snap shackle. Gather the sail under the boom. secures the afterguy to the clew of the sail. You may have to modify your existing pole. Beyond that you need to run a trip line through the fairlead at the end of the spinnaker pole and loop it through the trip mechanism on the Sparcraft shackle, i.e., the one on the afterguy. When the spinnaker is flying the trip line just dangles...
Spinnaker Trip Mechanism for Easy Takedowns
There is an easy takedown system that the crew of Alaska Eagle developed during the 1981 Whitbread Race that served us very well, especially when the boat was sailing along on the edge of control. I have since used the system when cruising and introduced it to others. The consensus is that it takes away one element of concern when sailing with a spinnaker that all-important element of releasing the sail to get it down. In order to use this technique you will need a pole guy, and a spinnaker...
Pbo
PBO is currently at the top of the performance pyramid when measured against other fibers, and it offers an option for out-and-out grand prix racers who want to save weight and increase the overall performance of their sails. It was initially developed by Dow Chemical, but because Dow is not in the business of making fibers, the technology was sold to the Japanese company Toyobo, which now produces the fibers under the trade name Zylon. PBO is a liquid crystal polymer that weight-for-weight has...
Explain how the mainsail trimmer can drive the boat
The mainsail is a huge sail that has a large effect on the weather helm and heel of the boat. If the sail is sheeted on too tight or if it is too high up the traveler, the helmsman will have to turn the wheel to compensate and this can slow the boat down, especially if there is a sudden puff of wind. Rather than wait for a puff of wind to hit the sails before easing the sheet, the mainsail trimmer can ease it before the wind hits the sail and save the helmsman from having to turn the wheel.
Foam Luff Pads
more turns more girth more shape removal flatter sail To compensate for a sail bagging out when reefed, sailmakers add a foam luff pad that runs the length of the luff Low-aspect sails need a foam luff pad more than high-aspect sails because they have more shape over a larger area to remove. While there may be less need for a foam luff pad on a high aspect sail, all sails will benefit from having one Figure 7.7 . Even though it can remove shape, the luff pad does nothing to help keep the shape...
Flaking a Headsail
Before a headsail is stuffed in its genoa turtle, you should be sure to flake the luff of the sail carefully on top of itself so that the next time you need to raise it the luff will feed out easily. A genoa turtle is used by racing sailors and is a long, sausage-like bag that can be either the same length as the foot of the headsail or one third the length of the foot of the sail. It's much easier to bag a headsail when it can first be done up in a turtle. You can then fold the turtle over on...