![181 PoortBrug Leeuwarden](https://upload.wikimedia.org/wikipedia/commons/3/38/181_PoortBrug_Leeuwarden.jpg)
A drawbridge or draw-bridge is a type of
moveable bridge
A moveable bridge, or movable bridge, is a bridge that moves to allow passage for boats or barges. In American English, the term is synonymous with , and the latter is the common term, but drawbridge can be limited to the narrower, historical d ...
typically at the entrance to a
castle
A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. Scholars debate the scope of the word ''castle'', but usually consider it to be the private fortified r ...
or tower surrounded by a
moat
A moat is a deep, broad ditch, either dry or filled with water, that is dug and surrounds a castle, fortification, building or town, historically to provide it with a preliminary line of defence. In some places moats evolved into more extensive ...
. In some forms of English, including
American English
American English, sometimes called United States English or U.S. English, is the set of variety (linguistics), varieties of the English language native to the United States. English is the Languages of the United States, most widely spoken lan ...
, the word ''drawbridge'' commonly refers to all types of moveable bridges, such as
bascule bridges,
vertical-lift bridge
A vertical-lift bridge or just lift bridge is a type of movable bridge in which a span rises vertically while remaining parallel with the deck.
The vertical lift offers several benefits over other movable bridges such as the bascule and swin ...
s and
swing bridge
A swing bridge (or swing span bridge) is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its center of gravity, about which the swing span (turning span) can then pi ...
s, but this article concerns the narrower historical definition of the term where the bridge is used in a defensive structure.
As used in castles or defensive structures, drawbridges provide access across defensive structures when lowered, but can quickly be raised from within to deny entry to an enemy force.
Castle drawbridges
Medieval
In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the Post-classical, post-classical period of World history (field), global history. It began with t ...
castle
A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. Scholars debate the scope of the word ''castle'', but usually consider it to be the private fortified r ...
s were usually defended by a ditch or
moat
A moat is a deep, broad ditch, either dry or filled with water, that is dug and surrounds a castle, fortification, building or town, historically to provide it with a preliminary line of defence. In some places moats evolved into more extensive ...
, crossed by a wooden bridge. In early castles the bridge might be designed to be destroyed or removed in the event of an attack, but drawbridges became very common. A typical arrangement would have the drawbridge immediately outside a
gatehouse
A gatehouse is a type of fortified gateway, an entry control point building, enclosing or accompanying a gateway for a town, religious house, castle, manor house, or other fortification building of importance. Gatehouses are typically the mos ...
, consisting of a wooden
deck with one edge
hinge
A hinge is a mechanical bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation: all other ...
d or pivoting at the gatehouse threshold, so that in the raised position the bridge would be flush against the gate, forming an additional barrier to entry. It would be backed by one or more
portcullis
A portcullis (from Old French ''porte coleice'', "sliding gate") is a heavy vertically-closing gate typically found in medieval fortifications, consisting of a latticed grille made of wood, metal, or a combination of the two, which slides down gr ...
es and gates. Access to the bridge could be resisted with missiles from
machicolations
A machicolation (french: mâchicoulis) is a floor opening between the supporting corbels of a battlement, through which stones or other material, such as boiling water, hot sand, quicklime or boiling cooking oil, could be dropped on attackers at t ...
above or
arrow slits
An arrowslit (often also referred to as an arrow loop, loophole or loop hole, and sometimes a balistraria) is a narrow vertical aperture in a fortification through which an archer can launch arrows or a crossbowman can launch bolts.
The interio ...
in flanking
tower
A tower is a tall Nonbuilding structure, structure, taller than it is wide, often by a significant factor. Towers are distinguished from guyed mast, masts by their lack of guy-wires and are therefore, along with tall buildings, self-supporting ...
s.
The bridge would be raised or lowered using ropes or chains attached to a
windlass
The windlass is an apparatus for moving heavy weights. Typically, a windlass consists of a horizontal cylinder (barrel), which is rotated by the turn of a crank or belt. A winch is affixed to one or both ends, and a cable or rope is wound arou ...
in a chamber in the gatehouse above the gate-passage. Only a very light bridge could be raised in this way without any form of counterweight, so some form of
bascule
Bascule may refer to:
* Bascule bridge, a moveable bridge with a counterweight that continuously balances the span in providing clearance for boat traffic
* Bascule (horse), the arc a horse's body takes as it goes over a jump
* Bascule light, a sma ...
arrangement is normally found. The bridge may extend into the gate-passage beyond the pivot point, either over a pit into which the internal portion can swing (providing a further obstacle to attack), or in the form of counterweighted beams that drop into slots in the floor.
The raising chains could themselves be attached to counterweights. In some cases, a portcullis provides the weight, as at
Alnwick
Alnwick ( ) is a market town in Northumberland, England, of which it is the traditional county town. The population at the 2011 Census was 8,116.
The town is on the south bank of the River Aln, south of Berwick-upon-Tweed and the Scottish bor ...
. By the 14th century a
bascule arrangement was provided by lifting arms (called "gaffs") above and parallel to the bridge deck whose ends were linked by chains to the lifting end of the bridge; in the raised position the gaffs would fit into slots in the gatehouse wall ("rainures") which can often still be seen, as at
Herstmonceux Castle
Herstmonceux Castle is a brick-built castle, dating from the 15th century, near Herstmonceux, East Sussex, England. It is one of the oldest significant brick buildings still standing in England. The castle was renowned for being one of the f ...
. Inside the castle the gaffs were extended to bear counterweights, or might form the side-timbers of a stout gate which would be against the roof of the gate-passage when the drawbridge was down, but would close against the gate-arch as the bridge was raised.
In France, working drawbridges survive at a number of
château
A château (; plural: châteaux) is a manor house or residence of the lord of the manor, or a fine country house of nobility or gentry, with or without fortifications, originally, and still most frequently, in French-speaking regions.
Nowaday ...
x, including the
Château du Plessis-Bourré
Château du Plessis-Bourré is a château in the Loire Valley in France, situated in the commune of Écuillé in the Maine-et-Loire department.
Built in less than 5 years from 1468 to 1472 by Finance Minister Jean Bourré, the principal advisor ...
. In England, two working drawbridges remain in regular use at
Helmingham Hall
Helmingham Hall is a moated manor house in Helmingham, Suffolk, England. It was begun by John Tollemache in 1480 and has been owned by the Tollemache family ever since. The house is built around a courtyard in typical late medieval/Tudor style. ...
, which dates from the early sixteenth century.
Turning bridge
A bridge pivoted on central
trunnion
A trunnion (from Old French "''trognon''", trunk) is a cylindrical protrusion used as a mounting or pivoting point. First associated with cannons, they are an important military development.
Alternatively, a trunnion is a shaft that positions a ...
s is called a ''turning bridge'', and may or may not have the raising chains characteristic of a drawbridge. The inner end carried counterweights enabling it to sink into a pit in the gate-passage, and when horizontal the bridge would often be supported by stout pegs inserted through the side walls. This was a clumsy arrangement, and many turning bridges were replaced with more advanced drawbridges.
Forts
![Drawbridge](https://upload.wikimedia.org/wikipedia/commons/c/cd/Drawbridge.gif)
Drawbridges were also used on forts with
Palmerston Forts
The Palmerston Forts are a group of forts and associated structures around the coasts of the United Kingdom and Ireland.
The forts were built during the Victorian period on the recommendations of the 1860 Royal Commission on the Defence of the ...
using them in the form of
Guthrie rolling bridge
A Guthrie rolling bridge was a kind of retractable bridge, an 18th-century version of the drawbridge. It was commonly installed as the access across the narrow steep sided ditches characteristic of the polygonal forts of this era.
Rolling bridg ...
s.
In art
Drawbridges have appeared in films as part of castle sets.
When the drawbridge needs to be functional this may present engineering challenges since the set may not be able to support the weight of the bridge in the conventional manner.
One solution is to build the drawbridge from steel and concrete before hiding the structural materials behind wood and plaster.
See also
*
Bascule bridge
*
Double-beam drawbridge
A double-beam drawbridge, seesaw or folding bridge is a movable bridge . It opens by rotation about a horizontal axis parallel to the water. Historically, the double-beam drawbridge has emerged from the drawbridge. Unlike a drawbridge, a double ...
*
Drawbridge mentality A drawbridge mentality is the attitude of people who have migrated to a more exclusive or more "unspoiled" community and then campaign to preserve the tranquility of that community by opposing further inward migration by people or businesses and, po ...
*
Portcullis
A portcullis (from Old French ''porte coleice'', "sliding gate") is a heavy vertically-closing gate typically found in medieval fortifications, consisting of a latticed grille made of wood, metal, or a combination of the two, which slides down gr ...
*
Linkspan
A linkspan or link-span is a type of drawbridge used mainly in the operation of moving vehicles on and off a roll-on/roll-off (RO-RO) vessel or ferry, particularly to allow for tidal changes in water level.
Linkspans are usually found at ferry t ...
*
Moveable bridges
A moveable bridge, or movable bridge, is a bridge that moves to allow passage for boats or barges. In American English, the term is synonymous with , and the latter is the common term, but drawbridge can be limited to the narrower, historical d ...
for a list of other movable bridge types
References
{{Authority control
Castle architecture
Moveable bridges