Blockhouse
Encyclopedia
Military science
Military science is the process of translating national defence policy to produce military capability by employing military scientists, including theorists, researchers, experimental scientists, applied scientists, designers, engineers, test technicians, and military personnel responsible for...
, a blockhouse is a small, isolated fort
Fortification
Fortifications are military constructions and buildings designed for defence in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs...
in the form of a single building. It serves as a defensive strong point against any enemy that does not possess siege equipment
Siege
A siege is a military blockade of a city or fortress with the intent of conquering by attrition or assault. The term derives from sedere, Latin for "to sit". Generally speaking, siege warfare is a form of constant, low intensity conflict characterized by one party holding a strong, static...
or, in modern times, artillery
Artillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...
. A fortification intended to resist these weapons is more likely to qualify as a fortress
Fortification
Fortifications are military constructions and buildings designed for defence in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs...
or a redoubt
Redoubt
A redoubt is a fort or fort system usually consisting of an enclosed defensive emplacement outside a larger fort, usually relying on earthworks, though others are constructed of stone or brick. It is meant to protect soldiers outside the main defensive line and can be a permanent structure or a...
, or in modern times, be an underground bunker
Bunker
A military bunker is a hardened shelter, often buried partly or fully underground, designed to protect the inhabitants from falling bombs or other attacks...
.
Early blockhouses in England
Early blockhouses were designed solely to protect a particular area by the use of artillery, and they had accommodation only for the short-term use of the garrison. The first known example is the Cow Tower, NorwichCow Tower, Norwich
Cow Tower is an historic military tower that stands by the River Wensum in Norwich, Norfolk. It gets its name from the water meadow, once known as Cowholme, in which it stands. It is about 15.2m high, with an internal diameter of 7.3m...
, built in 1398, which was of brick and had three storeys with the upper storeys pierced for six guns each. The major period of construction was in the maritime defence programmes
Device Forts
The Device Forts, also known as Henrician Castles, are a series of artillery fortifications built to defend the southern coast of England by Henry VIII. After his divorce of Catherine of Aragon England was left politically isolated, and the peace of Nice between France and Spain in 1538 aroused...
of Henry VIII
Henry VIII of England
Henry VIII was King of England from 21 April 1509 until his death. He was Lord, and later King, of Ireland, as well as continuing the nominal claim by the English monarchs to the Kingdom of France...
between 1539 and 1545. They were built to protect important maritime approaches such as the Thames Estuary
Thames Estuary
The Thames Mouth is the estuary in which the River Thames meets the waters of the North Sea.It is not easy to define the limits of the estuary, although physically the head of Sea Reach, near Canvey Island on the Essex shore is probably the western boundary...
, the Solent
Solent
The Solent is a strait separating the Isle of Wight from the mainland of England.The Solent is a major shipping route for passengers, freight and military vessels. It is an important recreational area for water sports, particularly yachting, hosting the Cowes Week sailing event annually...
, and Plymouth
Plymouth
Plymouth is a city and unitary authority area on the coast of Devon, England, about south-west of London. It is built between the mouths of the rivers Plym to the east and Tamar to the west, where they join Plymouth Sound...
. Often sited in pairs, the blockhouses were not built to a common design, but usually consisted of a stone tower and bastion
Bastion
A bastion, or a bulwark, is a structure projecting outward from the main enclosure of a fortification, situated in both corners of a straight wall , facilitating active defence against assaulting troops...
or gun platform, which could be semi-circular, rectangular or irregular in shape. The last blockhouse of this type was Cromwell's Castle
Cromwell's Castle
Cromwell's Castle is on the island of Tresco in the Isles of Scilly .It is a coastal Gun Tower built by Oliver Cromwell in 1651-1652 as a replacement for King Charles's Castle. The guns were mounted on the roof above the garrison's living quarters and magazines. The tower was originally entered at...
, built in Scilly in 1651.
Age of Exploration
Originally blockhouses were often constructed as part of a large plan, to "block" access to vital points in the scheme. But from the Age of Exploration to the nineteenth century standard patterns of blockhouses were constructed for defence in frontier areas, particularly South AfricaSouth Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
Blockhouses may be made of masonry
Masonry
Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone, marble, granite, travertine, limestone; concrete block, glass block, stucco, and...
where available, but were commonly made from very heavy timber
Timber
Timber may refer to:* Timber, a term common in the United Kingdom and Australia for wood materials * Timber, Oregon, an unincorporated community in the U.S...
s, sometimes even logs arranged in the manner of a log cabin
Log cabin
A log cabin is a house built from logs. It is a fairly simple type of log house. A distinction should be drawn between the traditional meanings of "log cabin" and "log house." Historically most "Log cabins" were a simple one- or 1½-story structures, somewhat impermanent, and less finished or less...
. They were usually two or even three floors
Storey
A storey or story is any level part of a building that could be used by people...
, with all storeys being provided with embrasure
Embrasure
In military architecture, an embrasure is the opening in a crenellation or battlement between the two raised solid portions or merlons, sometimes called a crenel or crenelle...
s or loopholes, and the uppermost storey would be roofed. If the structure was of timber, usually the upper storey would project outward from the lower so the upper storey defenders could fire on enemies attacking the lower storey, or perhaps pour water on any fires. When the structure had only one storey, its loopholes were often placed close to the ceiling, with a bench lining the walls inside for defenders to stand on, so that attackers could not easily reach the loopholes.
Blockhouses were normally entered via a sturdy, barred door at ground level. Most blockhouses were roughly square in plan
Plan
A plan is typically any diagram or list of steps with timing and resources, used to achieve an objective. See also strategy. It is commonly understood as a temporal set of intended actions, through which one expects to achieve a goal...
, but some of the more elaborate ones were hexagonal or octagonal, to provide better all-around fire. In some cases, blockhouses became the basis for complete forts, by building a palisade
Palisade
A palisade is a steel or wooden fence or wall of variable height, usually used as a defensive structure.- Typical construction :Typical construction consisted of small or mid sized tree trunks aligned vertically, with no spacing in between. The trunks were sharpened or pointed at the top, and were...
with the blockhouse at one corner, and possibly a second tower at the opposite corner. Many historical stone blockhouses have survived, and a few timber ones have been restored at historical sites. In New Zealand, a number of one storey timber blockhouses survive from the New Zealand land wars
New Zealand land wars
The New Zealand Wars, sometimes called the Land Wars and also once called the Māori Wars, were a series of armed conflicts that took place in New Zealand between 1845 and 1872...
.
Second Boer War
During the Second Boer WarSecond Boer War
The Second Boer War was fought from 11 October 1899 until 31 May 1902 between the British Empire and the Afrikaans-speaking Dutch settlers of two independent Boer republics, the South African Republic and the Orange Free State...
the British forces build a large number of fortifications in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
, most of these were cheap corrugated iron structures, but around 441 were solid masonry blockhouses, many of which stand today. A range of designs were used in the construction of these blockhouses, but most were either two or three story structures built using locally quarried stone.
These blockhouses played a vital role in the protection of the railway lines and bridges that were key to the British military supply lines.
Concrete blockhouses
During World War IWorld War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
and World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, many types of blockhouses were built, when time allowed usually constructed of reinforced concrete
Reinforced concrete
Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...
. The major difference between a modern blockhouse and a bunker
Bunker
A military bunker is a hardened shelter, often buried partly or fully underground, designed to protect the inhabitants from falling bombs or other attacks...
is that a bunker is constructed mostly below ground level while a blockhouse is constructed mostly above ground level.
Some blockhouses like those constructed in England in 1940 were built in anticipation of a German invasion
British anti-invasion preparations of World War II
British anti-invasion preparations of the Second World War entailed a large-scale division of military and civilian mobilisation in response to the threat of invasion by German armed forces in 1940 and 1941. The British army needed to recover from the defeat of the British Expeditionary Force in...
, they were often hexagonal in shape and were called "pillboxes". About 28,000 pillboxes and other hardened field fortifications
British hardened field defences of World War II
British hardened field defences of World War II were small fortified structures constructed as a part of British anti-invasion preparations. They were popularly known as pillboxes by reference to their shape.-Design and development:...
were constructed of which about 6,500 still survive.
In London the Admiralty Citadel is one of the most sturdy above ground structures built during World War II. It was constructed in 1940–1941 as a bomb-proof operations centre for the Admiralty
Admiralty
The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...
, with foundations nine metres deep and a concrete roof six metres thick. It too was intended to serve as a strongpoint in defending against the feared invasion.
In Berlin and other cities during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
some massive blockhouses were built as air-raid shelters and anti-aircraft artillery platforms. They were called Hochbunker (literally, "high bunkers"; better translated as 'above ground bunkers', to distinguish them from the usual deep i.e. underground air raid shelters) and those that functioned as anti-aircraft artillery platforms were also called Flak tower
Flak tower
Flak towers were 8 complexes of large, above-ground, anti-aircraft gun blockhouse towers constructed in the cities of Berlin , Hamburg , and Vienna from 1940 onwards....
s. Some were over six stories high; several survive to this day because of the high cost of demolition. The Pallasstrasse air-raid shelter in Berlin-Schöneberg
Schöneberg
Schöneberg is a locality of Berlin, Germany. Until Berlin's 2001 administrative reform it was a separate borough including the locality of Friedenau. Together with the former borough of Tempelhof it is now part of the new borough of Tempelhof-Schöneberg....
has a post-war block of flats built over it. During the Cold War
Cold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
the shelter was in use as a NATO foodstore.
In the Guerrilla Phase of the Irish Civil War
Guerrilla Phase of the Irish Civil War
The Guerrilla Phase of the Irish Civil War began in August 1922, when the forces of the Irish Free State took all the fixed positions previously held by the Anti-Treaty or Republican forces....
(1922–23) - a network of blockhouses was constructed to protect the railways from guerrilla attacks.
Afghanistan 2006
Blockhouses and Sangars have become a feature of the 2006 conflict in Afghanistan, being used by the British coalition forces, amongst others, as strong points to control the contested Southern provinces. These positions have served to draw out the Taliban, who have taken to attacking repeatedly in numbers.Non-military
The reinforced building(s) used to protect personnel and control equipment near rocket launch padLaunch pad
A launch pad is the area and facilities where rockets or spacecraft lift off. A spaceport can contain one or many launch pads. A typical launch pad consists of the service and umbilical structures. The service structure provides an access platform to inspect the launch vehicle prior to launch....
s are also sometimes referred to as blockhouses, in analogy to the military structure.
See also
- Battery towerSiege towerA siege tower is a specialized siege engine, constructed to protect assailants and ladders while approaching the defensive walls of a fortification. The tower was often rectangular with four wheels with its height roughly equal to that of the wall or sometimes higher to allow archers to stand on...
- CaponierCaponierA caponier is a type of fortification structure. The word originates from the French word "caponnière" - which strictly means capon-cote i.e. chickenhouse.The fire coming from the feature A caponier is a type of fortification structure. The word originates from the French word "caponnière" -...
- Martello towerMartello towerMartello towers are small defensive forts built in several countries of the British Empire during the 19th century, from the time of the Napoleonic Wars onwards....
- British hardened field defences of World War IIBritish hardened field defences of World War IIBritish hardened field defences of World War II were small fortified structures constructed as a part of British anti-invasion preparations. They were popularly known as pillboxes by reference to their shape.-Design and development:...
- Blockhouse, Nova ScotiaBlockhouse, Nova ScotiaBlockhouse is a community in the Canadian province of Nova Scotia, located in the Lunenburg Municipal District in Lunenburg County .- History :...
- Sangar (fortification)
External links
- Pillbox Study Group
- Royal Engineers Museum: Blockhouses during the Anglo-Boer War (1899–1902)
- Berlin Air-raid Shelters, Flak Towers and Bunkers
- Pillboxes
- British World War 2 Fortifications
- The Fortress Study Group