Mast (sailing)

File:Mast zelikvor.jpg

Sails on a small ship as seen from below

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 mid-19th century, ships' masts were wooden, with wood continuing to be used for some vessels today. Originally, they were formed from single piece 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 (also called masts), known in order of rising height about the decks 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.

In a three-masted, square-sail carrying ship, the masts, given their standard names in bow to stern (front to back) order, are:

• 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

Some names given to masts in ships carrying other types of rig (where the naming is less standardised) are:

• Bonaventure mizzen: the fourth mast on larger Sixteenth Century galleons, typically lateen-rigged and shorter than the main mizzen.
• Jigger-mast: typically, where it is the shortest, the aft-most mast on vessels with more than three masts.
  • Sections: Jigger-mast lower — Jigger topmast — Jigger topgallant mast

File:Balclutha main topgallant mast.jpg

Main topgallant mast

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

File:Mast Stars and Stripes.jpg

Mast of the sailing yacht Stars and Stripes

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.

File:Masts.svg

Illustration of modern mast and wing-mast cross-sections, with sail

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.

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://web.archive.org/web/20080305025200/http://tallships.sailtraining.org/sailrigs.htm
• http://boatdesign.net/articles/mast-materials/
• UCLA MAC Dinghy Sailing OverviewPDF (4.24 MiB)