A sail plan is a drawing of a sailing craft, viewed from the side, depicting its sails, the spars that carry them and some of the rigging that supports the rig. By extension, "sail plan" describes the arrangement of sails on a craft. A sailing craft may be waterborne (a

ship A ship is a large watercraft, vessel that travels the world's oceans and other Waterway, navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally disti ...

boat A boat is a watercraft of a large range of types and sizes, but generally smaller than a ship, which is distinguished by its larger size or capacity, its shape, or its ability to carry boats. Small boats are typically used on inland waterways s ...

), an

iceboat An iceboat (occasionally spelled ice boat or traditionally called an ice yacht) is a recreational or competition sailing craft supported on metal runners for traveling over ice. One of the runners is steerable. Originally, such craft were boats w ...

, or a sail-powered land vehicle.

Purpose

Depending on the level of detail, a sail plan can be a visual inventory of the suit of sails that a sailing craft has, or it may be part of a construction drawing. The sail plan may provide the basis for calculating the center of effort on a sailing craft, necessary to compare with the center of resistance from the hull in the water or the wheels or runners on hard surfaces. Such a calculation involves the area of each sail and its geometric center, referenced from a specific point.

Sail inventory

Considerations for a sail inventory in a yacht include the type of sailing (cruising, racing, passage-making, etc.) and the weather conditions anticipated. An assessment starts with a sail plan that depicts each kind of sail under consideration. The sail plan becomes a guide for which sails to use under the anticipated weather conditions, while under way. Sail names encompass fore-and-aft rigs, square rigs, and rigs that encompass both types.

Fore-and-aft rig

A cutter-rigged yacht, intended for off-shore sailing might have a sail inventory that includes: a

mainsail A mainsail is a sail rigged on the main mast (sailing), mast of a sailing vessel. * On a square rigged vessel, it is the lowest and largest sail on the main mast. * On a fore-and-aft rigged vessel, it is the sail rigged aft of the main mast. T ...

, a roller furling

genoa Genoa ( ; ; ) is a city in and the capital of the Italian region of Liguria, and the sixth-largest city in Italy. As of 2025, 563,947 people live within the city's administrative limits. While its metropolitan city has 818,651 inhabitan ...

, and a working staysail for most wind conditions, and, for strong winds, a storm staysail and trysail. Sails for lighter winds would include a

spinnaker A spinnaker is a sail designed specifically for sailing off the wind on courses between a Point of sail#Reaching, reach (wind at 90° to the course) to Point of sail#Running downwind, downwind (course in the same direction as the wind). Spinna ...

, a drifter, and a mainsail with lighter sail cloth. Each sail has a separate set of considerations within the plan, for example with a performance sloop one may consider the following about its suit of sails: *

Mainsail A mainsail is a sail rigged on the main mast (sailing), mast of a sailing vessel. * On a square rigged vessel, it is the lowest and largest sail on the main mast. * On a fore-and-aft rigged vessel, it is the sail rigged aft of the main mast. T ...

: Lazy jacks, reefing points and battens * Jib: Roller furling or reefing * Spinnakers and drifters: Draft, weight and (a)symmetry address their applications

Square rig

A square-rigged sailing vessel carries both fore-and-aft sails, the jibs, staysails and mizzen sail, and square sails. Their naming conventions are: * For jibs, attached to a bow sprit, (from forward, aftwards): flying, outer, and inner jibs, and the fore-topmast staysail, forestaysail, and foresail. * For staysails between the foremast and the mainmast (from bottom to top): main, main-topmast, main-topgallant, and main-royal (...staysail). Staysails between other masts are similarly named. * The mizzen sail (or "spanker") is a gaff-rigged, fore-and-aft sail, mounted on the after side of the mizzenmast. It was used to help tack the vessel. * For square sails (from bottom to top): (fore, main, mizzen) ...sail, lower topsail, upper topsail, topgallant, royal, skysail.

Choice of rig

In the late 19th and early 20th centuries, choosing a sail plan for a displacement watercraft stemmed from the size and tonnage of the vessel, its purpose (working vessel, cargo vessel or yacht) and the anticipated winds in the region where it was expected to sail. In that period, sail plans might start from smallest to largest boat or ship in a hierarchy of sailing rigs: Yachts * Catboat with a single sail * Sloop with mainsail and jib * Yawl with a small mast behind the steering post * Ketch with a mizzenmast ahead of the steering post Working boats and coastal freighters * Cutter with a single mast and multiple headsails *

Schooner A schooner ( ) is a type of sailing ship, sailing vessel defined by its Rig (sailing), rig: fore-and-aft rigged on all of two or more Mast (sailing), masts and, in the case of a two-masted schooner, the foremast generally being shorter than t ...

with two or more masts Ocean-going merchant vessels *

Brig A brig is a type of sailing vessel defined by its rig: two masts which are both square rig, square-rigged. Brigs originated in the second half of the 18th century and were a common type of smaller merchant vessel or warship from then until the l ...

with two square-rigged masts *

Brigantine A brigantine is a two-masted sailing vessel with a fully square-rigged foremast and at least two sails on the main mast: a square topsail and a gaff sail mainsail (behind the mast). The main mast is the second and taller of the two masts. Ol ...

with square-rigged foremast and fore-and aft mizzen *

Barque A barque, barc, or bark is a type of sailing ship, sailing vessel with three or more mast (sailing), masts of which the fore mast, mainmast, and any additional masts are Square rig, rigged square, and only the aftmost mast (mizzen in three-maste ...

with two square-rigged masts and a fore-and-aft mizzen * Barquentine with one square-rigged mast and two fore-and-aft masts behind *

Full-rigged ship A full-rigged ship or fully rigged ship is a sailing ship, sailing vessel with a sail plan of three or more mast (sailing), masts, all of them square rig, square-rigged. Such a vessel is said to have a ship rig or be ship-rigged, with each mas ...

with three or more masts with square sails on each

Gallery

The following sail plans are at various scales. File:A sailing carriage constructed by Henry Oxenden Esq 1785 RMG PY8617.jpg, "Sailing carriage", 1785 File:Comet - spars & sails.jpg, Full-rigged clipper ship, ''Comet'', 1851 File:Fusi Yama.jpg, Barque, '' Fusi Yama'', 1865 File:FMIB 34074 Grampus.jpeg, Schooner, ''Grampus'', 1887 File:Windglider.svg, Sailboard File:Byte CII.svg, Byte dinghy File:470 dinghy.svg, 470 dinghy File:FD Configuration 1960 - 1992.svg, Flying Dutchman dinghy File:EScow sailplan.svg, E Scow File:49er skiff.svg, 49er dinghy File:Capricorn F18.jpg, Formula 18 catamaran File:J Class sail plan.svg, J Class yacht

References

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