Ahoy Sailors, now that you can navigate your sailboat through different weather conditions, it’s time to learn about all the different sails on your boat, how to sue them and what they do. Stay tuned for the next lesson, which will explain when to use the correct sail.
SOUTHERN CALIF.— A sail provides propulsive force via a lift and drag, depending on its angle of attack, its angle with respect to the apparent wind. Apparent wind is the air velocity experienced on the moving craft and is the combined effect of the true wind velocity with the sailing craft’s velocity. Sails work by “catching the wind” only when the boat is sailing downwind. The rest of the time, a sail is essentially an airplane wing standing on end and works the same way.
Types of yacht sails
The types of yacht sails include:
- Mainsail: The larger sail aft (behind) the mast, attached to the mast and the boom
- Headsail: The sail between the forestay line and the mast. There are several sizes of headsails, either a jib, a genoa, or a spinnaker: A working jib is a smaller jib that fills the space between the mast and forestay, used in stronger winds. A genoa jib, on the other hand, overlaps the mainsail, providing maximum power in light winds
- Spinnaker: A sizeable balloon-type sail attached to the mast at the bow (front) of the boat, used when sailing downwind
Other types of sails:
- Jib – triangular staysail. Its tack is fixed to the bowsprit, the bows, or the deck between the bowsprit and the foremost mast. Jibs and spinnakers are the two main types of headsails on a modern boat.
- Genoa – large jib that overlaps the mainsail. It was initially called an “overlapping jib” and later a genoa jib. It is used on single-masted sloops and twin-masted boats such as yawls and ketches. Its larger surface area increases the craft’s speed in light to moderate winds; in high wind, a smaller jib is usually substituted, and downwind a spinnaker may be used.
- Gennaker – a crossover between a Genoa and Spinnaker. It is not symmetric like a true spinnaker but is asymmetric like a genoa, but the gennaker is not attached to the forestay like a jib or genoa. The gennaker is rigged like a spinnaker, but the tack is fastened to the hull or a bowsprit. It has a more significant camber than a genoa (but significantly less camber than a spinnaker). This is optimal for generating lift at larger angles of attack.
- Code Zero or Screecher – upwind spinnaker. The Code Zero is a cross between a genoa and an asymmetrical spinnaker used to sail close to the wind in light air. Code Zero was initially an attempt to circumvent a rating rule by making a large genoa for close reaching on boats measured with non-overlapping genoas.
- Drifter or reacher – A “drifter” is a lightweight sail designed to help cruisers keep moving in very light air. It is usually roughly the same cut as a genoa but made from nylon spinnaker-like material. It is typically colorful, lightweight, and large.
- Windseeker – tall, narrow, high-clewed, and lightweight jib. This is a very light sail for drifting conditions used when a full-size, heavier weight sail will not pressurize or remain stable.
- Trysail – smaller front-and-aft mainsail for heavy weather. A trysail (also known as a spencer) is a small triangular or square fore-and-aft rigged sail hoisted in place of a larger mainsail when winds are very high. The trysail provides enough thrust to maintain control of the ship, e.g., avoid ship damage and keep the bow to the wind. It is hoisted abaft (i.e., directly behind) the mainmast (taking the place of the much larger mainsail) or, on a brig, abaft the foremast. A trysail is analogous to a storm jib.
- Storm jib – small jib for heavy weather. Usually small and robust, a storm jib sail is made of durable, heavyweight fabric and is generally set either on the forestay or an inner forestay. The tack is usually set by way of a strop which is itself attached to the deck. This allows this relatively small, Yankee-cut sail to be rigged quite high off the deck, clear of any green water that is likely to be washing across the foredeck in a heavy sea.
There are a variety of sails that hold different functionalities; although they may not be used all the time, they are equally as essential and are likely to be carried on most sailing yachts. Functional sails include downwind sails, light air or reacher sails, and storm sails; they ensure the crew can handle the vessel in any weather condition and at any speed.
Parts of the sail
Before we dive into the different fabrics that can be used for yacht sails, it is important to understand the different sail parts.
Sail parts include:
- Head: Top of the sail
- Tack: Lower front corner of the sail
- Foot: Bottom of the sail
- Luff: Forward edge of the sail
- Leech: Back edge of the sail
- Clew: Bottom back corner of the sail
Superyacht sail fabrics
Sail fabrics and materials have, and continue to, develop at a rapid pace. Currently, sailing yachts can sport anything from Dacron crosscut sails built for recreational cruising to carbon and UHMWPE laminates made for competitive racing.
Fabric options for working sails can be divided into three main categories:
- Woven fabrics: A long-lasting and cost-effective product; however, it has low shape retention and is heavier than other available options.
- Laminated for paneled sails: Less durable overall but offer much better shape retention and lighter construction than woven sails.
- Laminated membranes: Built-in large sections, these offer the best shape retention. They are light and durable, but they come in at the most expensive.
Sail material should be chosen to suit the specific yacht type, yacht size, and the level of sailing the vessel will be doing, whether cruising or racing.
When choosing a supplier to fit out the masts and rigging of a superyacht, as with all yard work, it’s important to find a supplier with which you have a good working relationship.
There is a worldwide network of sail lofts and sailmakers to choose from, each with different strengths and weaknesses.
More on Sails:
- When properly trimmed (adjusted or positioned), the sail’s leading edge—the luff—points into the wind, creating higher pressure on the windward side (the side facing the wind) and lower pressure on the leeward side (the side away from the wind).”
- The sail “lifts,” or moves, toward the lower-pressure side, causing the boat to move. This happens because the sail isn’t a flat sheet of cloth; it’s curved, like a wing and the air traveling over the topside of the curved portion travels faster than that traveling on the underside. (The curvature, or “draft,” is built-in by the sailmaker through careful cutting and sewing of the narrow panels that make up the sail.)
- Not all the lift developed by a sail moves the boat ahead. Since the direction of lift is roughly at right angles to the sail, some of it tries to pull the boat sideways, too—but the shape of the hull and keel combined with the rudder creates a high resistance to the sideways force, “driving” the boat ahead.
- How much of the total lift acts to pull the boat forward and how much sideways depends on the “point of sail,” the angle between the boat and the wind: Closer to the wind = more sideways component because the sail is trimmed in closer to the centerline of the boat.
Because of this, when “beating” into the wind, most sailboats move a little bit sideways and ahead. Sailors call this “making leeway” and always consider it when navigating or sailing in close quarters.