Types of sails

By purpose, all sails are divided into:

• square sails — set across the vessel
• fore-and-aft sails — set along the vessel’s centerline
• studding sails — used to increase speed in light winds
• storm sails — used to reduce sail area due to weather conditions.

Square sails

Square sail

Square sails are the main sails of large and medium ocean-going sailing vessels, reaching their peak development on clippers. They have a four-sided shape—rectangular or trapezoidal—and are attached along their upper edge to a yard.

The lower edge, usually slightly curved upward, is secured with sheets and tacks to the yard below or to the ship’s deck. In areas of greatest stress, the sail is reinforced with horizontal bands and vertical bolt ropes.

Square sails are easy to rig and set, and can be readily divided into smaller sections. They are widely used, but tacking with them is extremely inconvenient, as the minimum effective angle between the wind direction and the vessel’s centerline at the bow is about 67 degrees.

Fore-and-aft sails

Fore-and-aft sails are more diverse and serve as the primary sail rig for small vessels and yachts. Vessels equipped only with fore-and-aft sails are able to sail closer to the wind. Modern yachts with such sails can sail close-hauled at an angle of about 35–40 degrees. Fore-and-aft sails include:

• lateen sails
• bermudian sails
• lug sails
• sprit sails
• gaff sails
• jibs
• staysails

Lateen sails

Lateen sail

Lateen sails are triangular in shape and are attached to a yard along their longest side; in the vessel’s centerline plane, they are stretched toward the stern using a sheet. They allow a vessel to sail at an angle of about 20 degrees relative to the wind direction.

Lateen sails are named according to the mast to which they belong, namely: fore lateen, main lateen, and mizzen lateen.

Bermudian sails

Bermudian sail

The bermudian sail is the most common sail on yachts, recreational, and racing vessels. It has a triangular shape, with its leading edge (luff) stretched along the mast and its lower edge (foot) along the boom.

In terms of ease of handling, setting, and driving performance, it is an undisputed leader. A yacht with properly trimmed Bermuda sails can be operated for long periods by a single person.

Lug sails

Lug sail

Lug sails (yard sails) are a разновидность lateen sails. Their upper edge is attached to a short yard, with the halyard secured at about one-third of the yard’s length from the forward end.

The lower forward corner of the sail is hauled toward the bow, while the aft corner is hauled toward the stern.

Sprit sails

Sprit sail

A sprit sail is a trapezoidal sail with a sharp aft peak, which is stretched by a diagonally positioned spar called a sprit. The lower end of the sprit rests against a fitting on the mast, while the upper end presses against the aft peak of the sail.

Gaff sails

Gaff sail

A gaff sail has the shape of an irregular trapezoid. Its head is attached to the gaff, the foot to the boom, and the luff to the mast using hoops, a track with slides, or by lacing. It originated in the early 17th century as a development of the lateen sail.

Jibs

Jib

A jib is a triangular fore-and-aft sail set on a stay running from the mast to the bowsprit. Large sailing ships may carry several jibs. In such cases, the forward-most jib set on the jibboom is called a flying jib, while the one closest to the mast is usually called the fore staysail.

On yachts, a larger light-wind jib is sometimes called a balloon jib. The jib is often confused with the staysail; the difference is that the foot of a staysail is positioned above the deck, whereas the foot of a jib is typically located above the bowsprit.

Staysails

Staysail

A staysail is the most common triangular sail set forward of the foremast. When multiple headsails are set, the sail closest to the mast is called a staysail, while the one further forward is the jib. Multi-masted vessels can carry staysails on each mast. A large staysail is called a genoa.

Studding sails

Sails that are added to the vessel’s main sails to increase speed in light winds are called studding sails. To increase the total sail area, vessels use trapezoidal studding sails and topgallant studding sails set alongside the topsails and topgallant sails, as well as triangular or quadrilateral lower studding sails set alongside the courses (fore and main sails).

Studding sails on the barque Europa

Storm Sails

In extremely strong winds, the mainsail is taken down and replaced with a trysail, which helps keep the vessel under control in heavy weather. The trysail is one of the storm sails used on yachts and serves as a substitute for the mainsail during severe conditions. Its foot is laced to the boom, the head is attached to the gaff, and the luff is secured to the mast (or a trysail mast) or to slides running along the mast. In bad weather, a jib may also be set.

Storm sails - trysail (left) and jib (right)

Sail types

Junk Sail

In the East, sail design developed in a simpler yet effective way. On traditional vessels known as junks, sails with horizontal curvature are used, providing efficient handling. The Chinese junk sail features rigid elements called battens that run across the full width of the sail and extend it forward of the mast. It is easy to handle and manufacture, offering reliability and versatility in all wind directions.

Junk sail

Oceanic Sprit Sail

An even more distinctive sail is used by Polynesian sailors. The Oceanic sprit sail, also known as the “crab claw sail,” is a type of triangular lateen sail set on traditional canoes such as proas and outrigger vessels. Its aerodynamic behavior differs from typical sails: airflow is directed toward the вершина равнобедренного треугольника, creating strong vortices along the edges and negative pressure on the inner side. As a result, thrust increases by up to 1.7 times, as confirmed in wind tunnel tests. Its curved shape also improves efficiency on beam winds by preventing airflow separation.

Oceanic sprit sail (or crab claw sail)

Spinnaker

Headsails provide the main driving force when sailing with the wind. The spinnaker is the largest sail on a sailing yacht and is used on downwind courses. It is a very light, balloon-shaped sail. Typically, when the spinnaker is set, other sails such as the jib and gennaker are taken down.

Spinnaker

Gennaker

The gennaker is a special type of headsail. It is a fore-and-aft sail with a high clew, often serving as an alternative to both the spinnaker and genoa. In size, it is larger than a genoa but smaller than a spinnaker. The sail is attached at the bow or bowsprit by its tack, while the clew is controlled by a sheet or extended to windward using a whisker pole. The gennaker performs well across a wide range of points of sail—from close-hauled to broad reach.

The yacht is sailing under a blue gennaker

Sail Parts

On square sails, the edges are called the head, foot, and the two leeches (right and left). A triangular fore-and-aft sail typically has three edges: the luff (front), leech (aft), and foot (bottom).

Each corner also has its own name:

• the top corner is the head (where the halyard is attached to hoist the sail)
• the aft corner is the clew (where the sheet is attached to control the sail)
• the forward corner is the tack

Conclusion

Sails are the primary element of any sailing vessel. Acting as both the “engine” and part of the steering system, they come in various shapes and sizes. Sail area can be reduced using a technique called reefing. The total area of all sails is referred to as sail area, while the complete set of sails is called the ship`s sail rigging.