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The mast of a sailing vessel is a tall spar, or arrangement of spars, erected more or less vertically on the centre-line of a ship or boat. Its purposes include carrying sail, spars, and derricks, and giving necessary height to a navigation light, look-out position, signal yard, control position, radio aerial or signal lamp.〔Layton, Cyril Walter Thomas, Peter Clissold, and A. G. W. Miller. Dictionary of nautical words and terms. Brown, Son & Ferguson, 1973.〕 Large ships have several masts, with the size and configuration depending on the style of ship. Nearly all sailing masts are guyed masts.〔Harland, John. ''Seamanship in the Age of Sail,'' pp. 22-5, Naval Institute Press, Annapolis, Maryland, 1992. ISBN 0-87021-955-3.〕 Until the mid-19th century all vessels' masts were made of wood formed from a single or several pieces of timber which typically consisted of the trunk of a conifer tree. From the 16th century, vessels were often built of a size requiring masts taller and thicker than could be made from single tree trunks. On these larger vessels, to achieve the required height, the masts were built from up to four sections (also called masts), known in order of rising height above 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. ==Nomenclature== In a three-masted, square-sail carrying ship, the masts, given their standard names in bow to stern (front to back) order, are: * Sprit topmast: a small mast set on the end of the bowsprit (discontinued after the early 18th century); not usually counted as a mast, however, when identifying a ship as "two masted" or "three masted" * Fore-mast: the first actual 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〔Harland, John. ''Seamanship in the Age of Sail,'' pp. 15, 19-22, 36-37, Naval Institute Press, Annapolis, Maryland, 1992. ISBN 0-87021-955-3.〕 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 aftmost mast on vessels with more than three masts. * * Sections: Jigger-mast lower—Jigger topmast—Jigger topgallant mast Most types of vessels with two masts are supposed to have a main-mast and a smaller mizzen-mast, although both brigs and two-masted schooners carry a fore-mast and a main-mast instead. On a two-masted vessel with the main-mast forward and a much smaller second mast, such as a ketch, or particularly a yawl, the terms ''mizzen'' and ''jigger'' are synonymous. Although two-masted schooners may be provided with masts of identical size, 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.〔Harland, John. ''Seamanship in the Age of Sail,'' pp. 20-2, Naval Institute Press, Annapolis, Maryland, 1992. ISBN 0-87021-955-3.〕 Folding mast ships use a tabernacle anchor point -- "the partly open socket or double post on the deck, into which a mast is fixed, with a pivot near the top so that the mast can be lowered",〔New Oxford American Dictionary (American English) via Apple Dictionary〕 "large bracket attached firmly to the deck, to which the foot of the mast is fixed; it has two sides or cheeks and a bolt forming the pivot around which the mast is raised and lowered", "substantial fitting for mounting the mast on deck, so that it can be lowered easily for trailering or for sailing under bridges",〔http://www.seatalk.info/cgi-bin/nautical-marine-sailing-dictionary/db.cgi?db=db&uid=default&FirstLetter=t&sb=Term&view_records=View+Records〕 "hinged device allowing for the easy folding of a mast 90 degrees from perpendicular, as for transporting the boat on a trailer, or passing under a bridge" 〔http://www.yourdictionary.com/tabernacle〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mast (sailing)」の詳細全文を読む スポンサード リンク
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