Gaff rig is a sailing

Sailing

Sailing is the propulsion of a vehicle and the control of its movement with large foils called sails. By changing the rigging, rudder, and sometimes the keel or centre board, a sailor manages the force of the wind on the sails in order to move the boat relative to its surrounding medium and...

 rig (configuration of sails) in which the sail

Sail

A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...

 is four-cornered, fore-and-aft rig

Fore-and-aft rig

A fore-and-aft rig is a sailing rig consisting mainly of sails that are set along the line of the keel rather than perpendicular to it. Such sails are described as fore-and-aft rigged....

ged, controlled at its peak and, usually, its entire head by a spar

Spar

In sailing, a spar is a pole of wood, metal or lightweight materials such as carbon fiber used on a sailing vessel. Spars of all types In sailing, a spar is a pole of wood, metal or lightweight materials such as carbon fiber used on a sailing vessel. Spars of all types In sailing, a spar is a...

 (pole) called the gaff. The gaff enables a fore and aft sail to be four sided, rather than triangular, and as much as doubles the sail area that can be carried by that mast and boom

Boom (sailing)

In sailing, a boom is a spar , along the foot of a fore and aft rigged sail, that greatly improves control of the angle and shape of the sail. The primary action of the boom is to keep the foot of the sail flatter when the sail angle is away from the centerline of the boat. The boom also serves...

 (if a boom is used in the particular rig). Additionally, for any given area of sail, the gaff rig will have a lower heeling moment than a triangular sail.

A sail hoisted from a gaff is called a gaffrigged sail.

Description

Gaff rig remains the most popular rig for schooner

Schooner

A schooner is a type of sailing vessel characterized by the use of fore-and-aft sails on two or more masts with the forward mast being no taller than the rear masts....

 and barquentine

Barquentine

A barquentine is a sailing vessel with three or more masts; with a square rigged foremast and fore-and-aft rigged main, mizzen and any other masts.-Modern barquentine sailing rig:...

 mainsails and other course sail

Course (sail)

In sailing, a course is the lowermost sail on a mast.This term is used predominantly in the plural to describe the lowest sails on a square rigged vessel, i.e., a ship's courses would be the foresail, mainsail, and, on the rare occasions in which one is shipped, mizen...

s, and spanker

Spanker (sail)

A spanker is either of two kinds of sail.On a square rigged ship, the spanker is a gaff rigged fore-and-aft sail set from and aft of the aftmost mast. Almost all square rigs with more than one mast have one or two spankers, which evolved from the driver sail. Some also carry a topsail above the...

 sails on a square rigged

Square rig

Square rig is a generic type of sail and rigging arrangement in which the primary driving sails are carried on horizontal spars which are perpendicular, or square, to the keel of the vessel and to the masts. These spars are called yards and their tips, beyond the last stay, are called the yardarms...

 vessel are always gaff rigged. On other rigs, particularly the sloop

Sloop

A sloop is a sail boat with a fore-and-aft rig and a single mast farther forward than the mast of a cutter....

, ketch

Ketch

A ketch is a sailing craft with two masts: a main mast, and a shorter mizzen mast abaft of the main mast, but forward of the rudder post. Both masts are rigged mainly fore-and-aft. From one to three jibs may be carried forward of the main mast when going to windward...

 and yawl

Yawl

A yawl is a two-masted sailing craft similar to a sloop or cutter but with an additional mast located well aft of the main mast, often right on the transom, specifically aft of the rudder post. A yawl (from Dutch Jol) is a two-masted sailing craft similar to a sloop or cutter but with an...

, gaff rigged sails were once common but have now been largely replaced by the bermuda rig

Bermuda rig

The term Bermuda rig refers to a configuration of mast and rigging for a type of sailboat and is also known as a Marconi rig; this is the typical configuration for most modern sailboats...

 sail, which, in addition to being simpler than the gaff rig, usually allows boats to sail closer to the direction the wind is coming from.

The gaff is hoisted by two halyard

Halyard

In sailing, a halyard or halliard is a line that is used to hoist a sail, a flag or a yard. The term halyard comes from the phrase, 'to haul yards'...

s:

• The throat halyard
  Throat halyard
  In sailing, the throat halyard is a line that raises the end of a gaff nearer to the mast, as opposed to the peak halyard which raises the end further from the mast. Such rigging was normal in classic gaff-rigged schooners and in other ships with fore-and-aft rigging. It is absent in Bermuda...
  
  lifts the end closer to the mast and bears the main weight of the sail and the tension of the luff.
• The peak halyard
  Peak halyard
  In sailing, the peak halyard is a line that raises the end of a gaff further from the mast, as opposed to the throat halyard which raises the end nearer to the mast. Such rigging was normal in classic gaff-rigged schooners and in other ships with fore-and-aft rigging...
  
  lifts the end further from the mast, and bears the leech tension.

Additionally, a gaff vang

Gaff vang

A gaff vang is a line on a gaff rig sailboat used to exert lateral force on the gaff and thus control the shape of the sail. Rarely used now they are commonly shown on old pictures and drawings. Typically separate port and starboard vangs were fitted. The primary purpose of the gaff vang is to...

 may be fitted. It is a line attached to the end of the gaff which prevents the gaff from sagging downwind. Gaff vangs are difficult to rig on the aft

Aft

Aft, in naval terminology, is an adjective or adverb meaning, towards the stern of the ship, when the frame of reference is within the ship. Example: "Able Seaman Smith; lay aft!". Or; "What's happening aft?"...

-most sail, so are typically only found on schooners or ketches, and then only on the foresail or mainsail.

A triangular fore-and-aft sail called a gaff topsail

Topsail

A topsail is a sail set above another sail; on square-rigged vessels further sails may be set above topsails.- Square rig :On a square rigged vessel, a topsail is a square sail rigged above the course sail and below the topgallant sail where carried...

 may be carried between the gaff and the topmast

Topmast

The masts of traditional sailing ships were not single spars, but were constructed of separate sections or masts, each with its own rigging. The topmast is one of these.The topmast is semi-permanently attached to the upper front of the lower mast, at the top...

 or the gaff and a jack-yard.

Gunter-rigged

Gunter

In sailing, a gunter is used for two main configurations of rig:#The gunter is defined as a wire that leads from one point near the end of a gaff to a point near the other end. A block travels along this wire, and a halyard is attached to this block...

 boats are similar, smaller vessels on which the gaff is raised by a single halyard running on a wire gunter. On these rigs the gaff may be very nearly vertical and a topsail is never carried. Another variation is a gaff with no halyard. One end of the spar is attached to the peak of the sail and the gaff is hoist until it tensions the head and leach and then the other end is secured to the mast near the tack with a Snotter

Snotter

A snotter is a rope or tackle used in sailing to tension the sprit on a spritsail, or a sprit boom on a sprit-boomed sail. It is also used in a junk rig....

 and are called Spritsails. This is considered a totally different rig.