Rig Sailing

The rig of a sailing vessel refers to the configuration of its mast or masts, sails, and rigging. Across maritime history and geographical regions, rigs developed in response to navigation needs, climatic conditions, ship design, and technological innovation. Modern single-handed sailing craft such as windsurfers, iceboats, and land yachts typically feature simple rigs consisting of a single mast, a boom, and one sail. Larger vessels, historical ships, and culturally distinctive watercraft may employ considerably more complex arrangements involving multiple masts and an array of sails.
A rig is conventionally represented using a sail plan: a profile drawing showing all sails in their hoisted positions alongside the masts, yards, booms, and rigging that support them. The design of a sail plan aims for balance, ensuring minimal pressure on the helm when maintaining course. Stability considerations limit the height of the sail plan’s centre of effort; hull shape, ballast distribution, and hull spacing in multihulls all influence how much sail area can be safely carried.

Historical Terminology and Development

During the early modern period, English nautical terminology tended to identify ships primarily by hull form rather than by rig type. This convention persisted until the late eighteenth century, after which the classification of vessels by rig became increasingly standard. The large fleets of colliers transporting coal from the north-eastern ports of England to London used hull terms such as bark and cat, even though many of these vessels were full-rigged ships with square sails on three masts. As the practice of removing square sails from the mizzenmast became common, the term bark evolved into barque, identifying a vessel with square sails on the foremast and mainmast but fore-and-aft sails on the mizzen. The Royal Navy’s description of HMS Endeavour as a “cat-built bark” illustrates the early overlap between hull and rig classifications.
The transition to rig-based nomenclature in the nineteenth century marked an important shift in maritime practice, emphasising the functional significance of sail arrangement for navigation, manoeuvrability, and crew requirements.

Principles of Sail Plan Design

A sail plan’s primary purpose is to define how a vessel harnesses wind power efficiently and safely. The centre of effort must lie slightly aft of the hull’s centre of resistance, allowing the vessel to turn gently into the wind if the helm is released. This weather helm ensures a measure of self-correcting stability.
Key factors influencing sail plan design include:

• Hull stability and ballast, determining resistance to heeling or capsize.
• Mast height and sail area, affecting performance and manoeuvrability.
• Windward and downwind performance, guiding the distribution of sail types.
• Rigging complexity, impacting crew size and operational practicality.

Types of Rig

Rigs fall broadly into two families: fore-and-aft rigs and square rigs. Many vessels employ hybrid arrangements.

Fore-and-Aft Rigs

These rigs carry sails aligned roughly along the vessel’s length. They allow efficient sailing to windward and are controlled primarily by sheets that shift from side to side when tacking.
Major variants include:

• Bermuda (Marconi) rig – a triangular mainsail attached to the mast and usually to a boom; widely used in modern yachts.
• Gaff rig – a four-sided mainsail supported at the top by a spar known as a gaff.
• Sprit rig – a four-sided sail supported by a diagonally mounted sprit.
• Lateen rig – a triangular sail mounted on an angled yard; historically important around the Mediterranean and Indian Ocean.
• Crab-claw sail – a three-sided sail with spars on both the foot and head, prominent in Austronesian sailing traditions.
• Tanja (canted rectangular) sail – a four-sided sail with spars along both upper and lower edges, common in Island Southeast Asia.

Square Rigs

Square-rigged vessels use large square sails suspended from horizontal spars called yards, which are typically mounted at right angles to the vessel’s centreline. These sails always present the same face to the wind and excel in downwind performance.
Many square-rigged ships use additional fore-and-aft sails such as staysails or jibs to improve manoeuvrability. A mast is considered “square-rigged” when square sails predominate, even if some auxiliary fore-and-aft sails are present.

Types of Sail

Different rigs require specialised sails, each serving a particular aerodynamic or operational purpose.

• Staysail – a fore-and-aft sail hanked to a stay.
• Headsail – any sail forward of the foremost mast; may include jibs or earlier square sails set from a bowsprit.
• Jib – a headsail set in front of other headsails. Larger vessels may carry multiple jibs such as flying, outer, and inner jibs.
• Genoa – an enlarged jib overlapping the mast and increasing sail area.
• Spinnaker – a lightweight ballooning sail used downwind in light airs.
• Gennaker – a hybrid of a genoa and a spinnaker.
• Mainsail – the principal sail attached to the main mast, taking various forms including Bermuda, gaff, spritsail, or square mainsails.
• Mizzen sail – carried on a mizzenmast on multi-masted vessels; may function as a steadying sail on motor vessels.

Distinctive sail shapes include the loose-footed square sail, the battened junk sail, the tall asymmetrical lugsail, the elongated settee sail, and the triangular Bermuda sail.

European and American Vessel Categories

Western maritime tradition classifies vessels according to mast arrangement and rig type.
Single-masted vessels included:

• Catboats
• Cutters
• Sloops

Two-masted vessels included:

• Bilanders
• Brigs
• Brigantines
• Ketches
• Schooners
• Snows
• Yawls

Three-masted vessels included:

• Barques
• Barquentines
• Polaccas
• Full-rigged ships

Luggers could carry one or two masts, while schooners might bear two or more.

Square-Rigged Mast Arrangement

In square-rigged ships, the standard three masts from bow to stern are the foremast, mainmast, and mizzenmast. Two-masted vessels pair a mainmast with either a foremast or a mizzenmast. Ships with more than three masts may number them sequentially or employ specific naming systems, as seen in large five-masted vessels.
Sails on each mast are named according to both mast and vertical position. For example, from lowest to highest on the mainmast:

• Main course
• Main topsail
• Main topgallant sail
• Main royal
• Main skysail
• Main moonraker

Higher sails were sometimes set on separate mast sections—topmasts or topgallant masts—supported by trestletrees. In light winds, studding sails (stunsails) could be deployed from the yardarms to increase sail area.
Staysails between masts were named by reference to the sails associated with the higher end of their supporting stays, such as the mizzen topgallant staysail. Jibs extended forward from the bowsprit, with fore topmast staysails, inner and outer jibs, and flying jibs forming the standard sequence.

Austronesian and East Asian Rigs

Maritime cultures of the Indian Ocean, Southeast Asia, and the Pacific developed distinctive rigs adapted to local shipbuilding traditions and seafaring needs. These included:

• Double sprit rigs in Sri Lanka
• Spritsails in the Philippines
• Oceanic sprit rigs in Tahiti and the Marquesas
• Crane-sprit rigs in the Marshall Islands
• Tanja sails in the Maluku Islands
• Lug sails around the Gulf of Thailand