sailboat A sailboat or sailing boat is a boat propelled partly or entirely by sails and is smaller than a sailing ship. Distinctions in what constitutes a sailing boat and ship vary by region and maritime culture. Types Although sailboat terminology ...

s, a sail batten is a flexible insert in a

sail A sail is a tensile structure, which is made from fabric or other membrane materials, that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails may b ...

, parallel to the direction of wind flow, that helps shape its qualities as an

airfoil An airfoil (American English) or aerofoil (British English) is a streamlined body that is capable of generating significantly more Lift (force), lift than Drag (physics), drag. Wings, sails and propeller blades are examples of airfoils. Foil (fl ...

. Battens are long, thin strips of material, historically wooden but today usually

fiberglass Fiberglass (American English) or fibreglass (English in the Commonwealth of Nations, Commonwealth English) is a common type of fibre-reinforced plastic, fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened i ...

vinyl Vinyl may refer to: Chemistry * Polyvinyl chloride (PVC), a particular vinyl polymer * Vinyl cation, a type of carbocation * Vinyl group, a broad class of organic molecules in chemistry * Vinyl polymer, a group of polymers derived from vinyl ...

, or carbon fiber, used to support the roach of a sail. They are also used on tall ships to form the ladders up the shrouds in a fashion similar to ratlines.

History

Battened sails are commonly found in junk ship. A junk is an ancient Chinese

sailing ship A sailing ship is a sea-going vessel that uses sails mounted on Mast (sailing), masts to harness the power of wind and propel the vessel. There is a variety of sail plans that propel sailing ships, employing Square rig, square-rigged or Fore-an ...

design that is still in use today. Iconographic remains show that Chinese ships before the 12th century used square sails. A ship carving from a stone Buddhist stele shows a ship with square sail from the Liu Sung dynasty or the Liang dynasty (ca. 5th or 6th century). Dunhuang cave temple no. 45 (from the 8th or 9th century) features large sailboats and sampans with inflated square sails. A wide ship with a single sail is depicted in the Xi'an mirror (after the 9th or 12th century).See also plates CDIII, CDIV, CDV, CDVI in Needham, Volume 4, Part 3. Eastern lug sail, which used battens and is commonly known as "junk rig", was likely not Chinese in origin: The oldest depiction of a battened junk sail comes from the Bayon temple at Angkor Thom, Cambodia.Needham, Joseph (1971).
Science and Civilisation in China: Volume 4, Physics and Physical Technology, Part 3, Civil Engineering and Nautics
'. Cambridge University Press. From its characteristics and location, it is likely that the ship depicted in Bayon was a Southeast Asian ship. The Chinese themselves may have adopted them around the 12th century CE. Their rigs featured full-length battens that facilitated short-handed sail handling, including reefing.

Applications in sails

The most common use of sail battens is in the roach of 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 ...

. The batten extends the

leech Leeches are segmented parasitism, parasitic or Predation, predatory worms that comprise the Class (biology), subclass Hirudinea within the phylum Annelida. They are closely related to the Oligochaeta, oligochaetes, which include the earthwor ...

past the line that runs from the

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple ani ...

and the clew of the sail to create a wider sail towards the top. Cruising

s may have four to six battens. Racing sailboats may have full-length battens, as well, that allow for better sail shape. Batten length near the head of the sail is limited by the need for the roach to pass ahead of the backstay, when tacking or jibing. Battens are also found in jibs of beach-cat catamarans.

Batten materials and construction

Most modern battens are fiberglass pultrusions with a thin, rectangular cross section. An alternative shape is a hollow tube that rotates in the batten pocket and is more compatible with roller furling the mainsail. Because the ends of battens are likely to chafe the sail at the ends of the pockets into which they are inserted, they often have a soft, blunt shape affixed to them.

References

{{Sail types Sailing rigs and rigging