Mast (sailing)
The mast of a sailing ship is a tall, vertical, or near vertical, spar, or arrangement of spars, which supports the sails. Large ships have several masts, with the size and configuration depending on the style of ship.
Until the 20th century, ships' masts were wooden. Originally, they were formed from single pieces of timber, typically the trunks of fir trees. From the 16th century, ships were often built of a size requiring masts taller and thicker than could be made from single tree trunks. On these larger ships, to achieve the required height, the masts were built from up to four sections, known in order of rising height about the sea as the lower, top, topgallant and royal masts. Giving the lower sections sufficient thickness necessitated building them up from separate pieces of wood. Such a section was known as a made mast, as opposed to sections formed from single pieces of timber, which were known as pole masts.
A ship's masts are named from bow to stern (front to back):
- Fore-mast: the first mast, or the mast fore of the main-mast.
- Sections: Fore-mast lower — Fore topmast — Fore topgallant mast
- Main-mast: the tallest mast, usually located near the center of the ship.
- Sections: Main-mast lower — Main topmast — Main topgallant mast — royal mast (if fitted)
- Mizzen-mast: the third mast, or the mast immediately aft of the main-mast. Typically shorter than the fore-mast.
- Sections: Mizzen-mast lower — Mizzen topmast — Mizzen topgallant mast
- Bonaventure mizzen: the fourth mast on larger Sixteenth Century galleons, typically lateen-rigged and shorter than the main mizzen.
- Jigger-mast: the fourth mast or the aft-most mast where it is smallest on vessels of less than four masts.
- Sections: Jigger-mast lower — Jigger topmast — Jigger topgallant mast
Mast names for other vessels generally follow this naming. Many ships would also have a bowsprit at an angle closer to the horizontal, extending forward of the prow.
Most types of ships with two masts would have a main-mast and a smaller mizzen-mast, although both brigs and two-masted schooners instead carry a fore-mast and main-mast. On a two-masted vessel with the mainmast forward and a much smaller second mast, such as a ketch, or particularly a yawl, the terms mizzen and jigger are synonymous.
Some two-masted schooners have masts of identical size, but the aftmost is still referred to as the main-mast, and normally has the larger course. Schooners have been built with up to seven masts in all, with several six-masted examples.
On square-rigged vessels, each mast carries several horizontal yards from which the individual sails are rigged.
Modern masts
Although sailing ships were superseded by engine-powered ships in the 19th century, recreational sailing ships and yachts continue to be designed and constructed. In the 1930s aluminium masts were introduced on large J-class yachts. Aluminium has considerable advantages over wooden masts, being lighter, stronger and impervious to rot; further, aluminium can be extruded as a single piece for the entire height of the mast. After the Second World War, extruded aluminium masts became common on all dinghies and smaller yachts. Higher performance yachts would use tapered aluminium masts, constructed by removing a triangular strip of aluminium along the length of the mast and then closing and welding the gap.
From the mid 1990s racing yachts introduced the use of carbon fibre and other composite materials to construct masts with even better strength-to-weight ratios. Carbon fibre masts could also be constructed with more precisely engineered aerodynamic profiles.
Modern masts form the leading edge of a sail's airfoil and tend to have a teardrop-shaped cross-section. On smaller racing yachts and catamarans, the mast rotates to the optimum angle for the sail's airfoil. If the mast has a long, thin cross-section and makes up a significant area of the airfoil, it is called a wing-mast; boats using these have a smaller sail area to compensate for the larger mast area.
On modern warships, the mast still exists but does not serve the purpose of holding sails, since all modern warships are engine-powered. Instead, the mast serves as a mounting point for radar and telecommunication antennas. This is beneficial because generally, the higher an antenna is mounted, the farther its range is.
See also
- Sailing ship
- Rigging
- Sail-plan
References
- http://www.bluewatersailing.com/shipclass.php
- http://www.hms-trincomalee.co.uk/virtual/rigging/sailsrev.htm
- http://tallships.sailtraining.org/sailrigs.htm
- http://boatdesign.net/articles/mast-materials/
- UCLA MAC Dinghy Sailing OverviewPDF (4.24 MiB)
|
||||||||||||||