A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lenses and to serve as a beacon for navigational aid for maritime pilots at sea or on inland waterways.
107-531: The Montauk Point Light , or Montauk Point Lighthouse , is a lighthouse located adjacent to Montauk Point State Park at the easternmost point of Long Island in Montauk, New York . The lighthouse was the first to be built within the state of New York , and was the first public works project of the new United States . It is the fourth oldest active lighthouse in the United States. Montauk Point Light
214-402: A rescue service , if necessary. Improvements in maritime navigation and safety, such Global Positioning System (GPS), led to the phasing out of non-automated lighthouses across the world. Although several closed due to safety concerns, Canada still maintains 49 staffed lighthouses, split roughly evenly across east and west coasts. The remaining modern lighthouses are usually illuminated by
321-410: A 6-inch gun, and had a 4-to-6-inch (100 to 150 mm) front plate (forming part of the side of the ship), with thinner armor plates on the sides and rear, with a protected top and floor, and weighed about 20 tons (not including the gun and mounting). Casemates were similar in size to turrets; ships carrying them had them in pairs, one on each side of the ship. The first battleships to carry them were
428-640: A Diesel generator for backup. Many Fresnel lens installations have been replaced by rotating aerobeacons , which require less maintenance. In modern automated lighthouses, the system of rotating lenses is often replaced by a high intensity light that emits brief omnidirectional flashes, concentrating the light in time rather than direction. These lights are similar to obstruction lights used to warn aircraft of tall structures. Later innovations were "Vega Lights", and experiments with light-emitting diode (LED) panels. LED lights, which use less energy and are easier to maintain, had come into widespread use by 2020. In
535-419: A casemate gun, which could be worked by hand. The use of casemates enabled the 6-inch guns to be dispersed, so that a single hit would not knock out all of them. Casemates were also used in protected and armored cruisers, starting with the 1889 Edgar class . and retrofitted to the 1888 Blake class during construction. In the pre-dreadnought generation of warships, casemates were placed initially on
642-436: A filament source. Experimental installations of laser lights, either at high power to provide a "line of light" in the sky or, utilising low power, aimed towards mariners have identified problems of increased complexity in installation and maintenance, and high power requirements. The first practical installation, in 1971 at Point Danger lighthouse , Queensland , was replaced by a conventional light after four years, because
749-457: A form of concrete that will set under water used by the Romans, and developed a technique of securing the granite blocks together using dovetail joints and marble dowels . The dovetailing feature served to improve the structural stability , although Smeaton also had to taper the thickness of the tower towards the top, for which he curved the tower inwards on a gentle gradient. This profile had
856-414: A horizontal plane, and horizontally the light is focused into one or a few directions at a time, with the light beam swept around. As a result, in addition to seeing the side of the light beam, the light is directly visible from greater distances, and with an identifying light characteristic . This concentration of light is accomplished with a rotating lens assembly. In early lighthouses, the light source
963-713: A lawyer, member of the Continental Congress in Philadelphia , and a man with scientific interests, consulted with Washington on its construction. He represented the New York City Chamber of Commerce on discussions related to the lighthouse. He made the case that New York City "was first among American ports in the volume of its foreign commerce. By 1797, the harbor was handling a third of the nation's trade with other countries." Due to prevailing winds in winter, shippers approaching from sea needed
1070-492: A lighthouse at the end of Long Island to guide them along the south side into New York harbor. L'Hommedieu chose the site for the lighthouse and designed it. The project began on June 7, 1796, and was completed on November 5, 1796, the first public works project of the new United States of America . Sometime in early April 1797, keeper Jacob Hand lit the wicks in the lamps in the tower, and the lighthouse began operation. It continued under civilian keepers until World War II , when
1177-427: A more powerful hyperradiant Fresnel lens manufactured by the firm of Chance Brothers . While lighthouse buildings differ depending on the location and purpose, they tend to have common components. A light station comprises the lighthouse tower and all outbuildings, such as the keeper's living quarters, fuel house, boathouse, and fog-signaling building. The Lighthouse itself consists of a tower structure supporting
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#17327752769561284-412: A navigational hazard about 3 1 ⁄ 2 miles northwest of the lighthouse. This light was severely damaged in the hurricane of September 21, 1938, and removed on July 1, 1940, when the lighthouse was electrified. The huge first-order Fresnel lens was replaced in 1903 with a 3 1 ⁄ 2 order bivalve Fresnel lens, which served until February 3, 1987, when it was replaced with an airport beacon with
1391-602: A navigator with a line of position called a range in North America and a transit in Britain. Ranges can be used to precisely align a vessel within a narrow channel such as a river. With landmarks of a range illuminated with a set of fixed lighthouses, nighttime navigation is possible. Such paired lighthouses are called range lights in North America and leading lights in the United Kingdom. The closer light
1498-477: A new scheme of fortifications to protect their eastern border, which became known as the Maginot Line . The main element of this line were large underground forts based on the feste principle, whose main armament was in turrets, however the countryside between them was defended by smaller self-sufficient works based on the earlier casemates de bourges , housing either light field guns or anti-tank guns . As
1605-521: A number of screw-pile lighthouses. Englishman James Douglass was knighted for his work on the fourth Eddystone Lighthouse. United States Army Corps of Engineers Lieutenant George Meade built numerous lighthouses along the Atlantic and Gulf coasts before gaining wider fame as the winning general at the Battle of Gettysburg . Colonel Orlando M. Poe , engineer to General William Tecumseh Sherman in
1712-402: A particular color (usually formed by colored panes in the lantern) to distinguish safe water areas from dangerous shoals. Modern lighthouses often have unique reflectors or racon transponders so the radar signature of the light is also unique. Before modern strobe lights , lenses were used to concentrate the light from a continuous source. Vertical light rays of the lamp are redirected into
1819-411: A reservoir mounted above the burner. The lamp was first produced by Matthew Boulton , in partnership with Argand, in 1784, and became the standard for lighthouses for over a century. South Foreland Lighthouse was the first tower to successfully use an electric light in 1875. The lighthouse's carbon arc lamps were powered by a steam-driven magneto . John Richardson Wigham was the first to develop
1926-470: A rotating turret as much as offensively used tanks, while assault guns were mainly used against fortified infantry positions and could afford a longer reaction time if a target presented itself outside the vehicle's gun traverse arc. Thus, the weight and complexity of a turret was thought to be unnecessary, and could be saved in favor of more capable guns and armor. In many cases, casemate vehicles would be used as both tank destroyers or assault guns, depending on
2033-415: A single stationary flashing light powered by solar-charged batteries and mounted on a steel skeleton tower. Where the power requirement is too great for solar power alone, cycle charging of the battery by a Diesel generator is provided. The generator only comes into use when the battery needs charging, saving fuel and increasing periods between maintenance. John Smeaton is noteworthy for having designed
2140-507: A strength of 2.5 million candela. However, as of November 6, 2023, the 3 1 ⁄ 2 order bivalve Fresnel lens that was replaced in 1987 has been restored and is now back atop the lighthouse. During World War II , the lighthouse was taken over by the U.S. Army as part of the Eastern Coastal Defense Shield. The last three civilian keepers, Thomas Buckridge, Jack Miller, and George Warrington, departed in
2247-477: A system for gas illumination of lighthouses. His improved gas 'crocus' burner at the Baily Lighthouse near Dublin was 13 times more powerful than the most brilliant light then known. The vaporized oil burner was invented in 1901 by Arthur Kitson , and improved by David Hood at Trinity House . The fuel was vaporized at high pressure and burned to heat the mantle, giving an output of over six times
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#17327752769562354-542: A translation of his book and took it to the United States, where it inspired the Second and Third Systems of coastal fortification; the first fully developed example being Castle Williams in New York Harbor which was started in 1807. In the early 19th century, French military engineer Baron Haxo designed a free-standing casemate that could be built on the top of the rampart, to protect guns and gunners from
2461-611: A turret for the main gun, the structure that accommodates the gun is also called a casemate. First recorded in French in the mid-16th century, from the Italian casamatta or Spanish casamata , perhaps meaning a slaughterhouse , although it could derive from casa (in the sense of " hut "), and matta ( Latin matta ), "done with reeds and wickers", thus a low-roof hut without windows or other openings set in marshy place. It could also come from casa matta with matta in
2568-487: A very low freeboard and their guns on the main deck ('Casemate deck') protected by a sloped armoured casemate, which sat atop the hull. Although both sides of the Civil War used casemate ironclads, the ship is mostly associated with the southern Confederacy , as the north also employed turreted monitors , which the south was unable to produce. The most famous naval battle of the war was the duel at Hampton Roads between
2675-450: Is a fortified gun emplacement or armoured structure from which guns are fired, in a fortification , warship , or armoured fighting vehicle . When referring to antiquity , the term " casemate wall " means a double city wall with the space between the walls separated into chambers, which could be filled up to better withstand battering rams in case of siege (see § Antiquity: casemate wall .) In its original early modern meaning,
2782-479: Is listed on the National Register of Historic Places . In 2012, it was designated as a National Historic Landmark for its significance to New York and international shipping in the early Federal period . The lighthouse, which is located on Turtle Hill at the easternmost tip of Long Island, at 2000 Montauk Highway, is a privately run museum, and is not part of Montauk Point State Park . Montauk Light
2889-419: Is one example. Race Rocks Light in western Canada is painted in horizontal black and white bands to stand out against the horizon. For effectiveness, the lamp must be high enough to be seen before the danger is reached by a mariner. The minimum height is calculated by trigonometry (see Distance to the horizon ) as D = 1.22 H {\displaystyle D=1.22{\sqrt {H}}} , where H
2996-485: Is referred to as the beacon or front range; the further light is called the rear range. The rear range light is almost always taller than the front. When a vessel is on the correct course, the two lights align vertically, but when the observer is out of position, the difference in alignment indicates the direction of travel to correct the course. There are two types of lighthouses: ones that are located on land, and ones that are offshore. Casemates A casemate
3103-510: Is the height above water in feet, and D is the distance from the lighthouse to the horizon in nautical miles, the lighthouse range . Where dangerous shoals are located far off a flat sandy beach, the prototypical tall masonry coastal lighthouse is constructed to assist the navigator making a landfall after an ocean crossing. Often these are cylindrical to reduce the effect of wind on a tall structure, such as Cape May Light . Smaller versions of this design are often used as harbor lights to mark
3210-622: The Florida Reef along the Florida Keys, beginning with the Carysfort Reef Light in 1852. In waters too deep for a conventional structure, a lightship might be used instead of a lighthouse, such as the former lightship Columbia . Most of these have now been replaced by fixed light platforms (such as Ambrose Light ) similar to those used for offshore oil exploration . Aligning two fixed points on land provides
3317-769: The SU-100 or the ISU-152 . Both Germany and the Soviet Union mainly built casemate AFVs by using the chassis of already existing turreted tanks, instead of designing them from scratch. While casemate AFVs played a very important role in World War II (the Sturmgeschütz III for example was the most numerous armored fighting vehicle of the German Army during the entire war), they became much less common in
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3424-529: The Union turreted ironclad USS Monitor and the Confederate casemate ironclad CSS Virginia (built from the scuttled remains of USS Merrimack ). "Casemate ship" was an alternative term for " central battery ship " (UK) or "center battery ship" (US). The casemate (or central battery) was an armored box that extended the full width of the ship protecting many guns. The armored sides of
3531-871: The World War II approached, similar casemate designs were adopted by other European nations as they offered protection from attacking aircraft. The German Organisation Todt undertook the development of casemates for the large coastal guns of the Atlantic Wall . Built of concrete up to 10 metres (33 ft) thick, they were thought to be able to withstand any form of attack. Work by the Western Allies to develop countermeasures that could defeat casemates and other types of bunker resulted in weapons such as tank-mounted spigot mortars , rocket-assisted projectiles , recoilless rifles , various types of demolition charge and earthquake bombs . In warship design
3638-413: The 17th century. In the late 18th century, Marc René, marquis de Montalembert (1714–1800) experimented with improved casemates for artillery, with ventilation systems that overcame the problem of smoke dispersal found in earlier works. For coastal fortifications , he advocated multi-tiered batteries of guns in masonry casemates, that could bring concentrated fire to bear on passing warships. In 1778, he
3745-513: The 20th century. These often have a narrow cylindrical core surrounded by an open lattice work bracing, such as Finns Point Range Light . Sometimes a lighthouse needs to be constructed in the water itself. Wave-washed lighthouses are masonry structures constructed to withstand water impact, such as Eddystone Lighthouse in Britain and the St. George Reef Light of California. In shallower bays, Screw-pile lighthouse ironwork structures are screwed into
3852-490: The British Royal Sovereign class laid down in 1889. They were adopted as a result of live-firing trials against HMS Resistance in 1888. Casemates were adopted because it was thought that the fixed armor plate at the front would provide better protection than a turret, and because a turret mounting would require external power and could therefore be put out of action if power were lost – unlike
3959-641: The Iron Age and peaking in Iron Age II (10th–6th century BC). However, the construction of casemate walls had begun to be replaced by sturdier solid walls by the 9th century BC , probably due the development of more effective battering rams by the Neo-Assyrian Empire . Casemate walls could surround an entire settlement, but most only protected part of it. The three different types included freestanding casemate walls, then integrated ones where
4066-780: The Point and kept the project moving forward after she retired in 1986. With support from various sources, including the Montauk Historical Society and the State of New York, the Erosion Control Project of Montauk Point was successfully completed in 1998. However, the recurrence of the erosion threat in ensuing years has prompted further action: In November 2006, the United States Army Corps of Engineers ' plan to build another seawall
4173-459: The Society at Montauk. Reid's concept, Reed-Trench Terracing, called for building the terrace platforms made of various beach debris, notably reeds; the practice (along with further strengthening of the rocks at the bluff toe) appeared to stem the erosion. She patented the process and published an article about it titled "How to Hold up a Bank". Greg Donohue, a Montauk landscaper, worked with Reid at
4280-466: The Swiss scientist Aimé Argand revolutionized lighthouse illumination with its steady smokeless flame. Early models used ground glass which was sometimes tinted around the wick. Later models used a mantle of thorium dioxide suspended over the flame, creating a bright, steady light. The Argand lamp used whale oil , colza , olive oil or other vegetable oil as fuel, supplied by a gravity feed from
4387-466: The US Army took it over. In 1860, the lighthouse station underwent a massive renovation when two new levels and a larger lantern were added. This increased the height of the tower from its original 80 feet (1796) to its current height of 110 feet 6 inches (33.68 metres). A first-order Fresnel lens —12 feet high, 6 feet (3.7 x 1.8 m) in diameter, and weighing about 10,000 pounds—was installed in
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4494-405: The United Kingdom and Ireland about a third of lighthouses had been converted from filament light sources to use LEDs, and conversion continued with about three per year. The light sources are designed to replicate the colour and character of the traditional light as closely as possible. The change is often not noticed by people in the region, but sometimes a proposed change leads to calls to preserve
4601-495: The added advantage of allowing some of the energy of the waves to dissipate on impact with the walls. His lighthouse was the prototype for the modern lighthouse and influenced all subsequent engineers. One such influence was Robert Stevenson , himself a seminal figure in the development of lighthouse design and construction. His greatest achievement was the construction of the Bell Rock Lighthouse in 1810, one of
4708-568: The announced dismantling of the tower, Congressman Michael Forbes proposed a bill to the United States Congress to hand over the Lighthouse to the Montauk Historical Society from the public so it could be preserved; the bill was passed. Giorgina Reid , a textile designer, had saved her Rocky Point, New York cottage from collapse by building a simple set of terraces in the gullies of the bluff. She proposed that solution to
4815-467: The arrival of "all-big gun" battleship, pioneered by HMS Dreadnought in 1906, but were reintroduced as the increasing torpedo threat from destroyers forced an increase in secondary armament calibre. Many battleships had their casemates plated over during modernization in the 1930s (or after the Attack on Pearl Harbor , in the case of US vessels) but some, like HMS Warspite carried them to
4922-489: The award of a $ 30.7 million contract to H&L Contracting of Bayshore, New York to restore and protect the lighthouse from shoreline erosion. Work began in 2021 and ended in August 2023. The approximately 1,000 linear feet stone revetment work consisted of removing and reusing existing five- and 10-ton armor stones, placement of new 10- and 15-ton armor stones, and providing slope stabilization with terracing and vegetation above
5029-491: The beam was too narrow to be seen easily. In any of these designs an observer, rather than seeing a continuous weak light, sees a brighter light during short time intervals. These instants of bright light are arranged to create a light characteristic or pattern specific to a lighthouse. For example, the Scheveningen Lighthouse flashes are alternately 2.5 and 7.5 seconds. Some lights have sectors of
5136-423: The box were the sides or hull of the ship. There was an armored bulkhead at the front and rear of the casemate, and a thick deck protecting the top. The lower edge of the casemate sat on top of ship's belt armour . Some ships, such as HMS Alexandra (laid down 1873), had a two-story casemate. A "casemate" was an armored room in the side of a warship, from which a gun would fire. A typical casemate held
5243-603: The capability to take up the roles and tasks which in the past had to be diverted between several different classes of vehicles. However, vehicles such as the German Kanonenjagdpanzer of the 1960s still let the casemate concept live on, while the Swedish Army went as far as employing a casemate tank design, the Stridsvagn 103 , or "S-Tank", as their main armored fighting vehicle from the 1960s until
5350-406: The choice of light sources, mountings, reflector design, the use of Fresnel lenses , and in rotation and shuttering systems providing lighthouses with individual signatures allowing them to be identified by seafarers. He also invented the movable jib and the balance-crane as a necessary part for lighthouse construction. Alexander Mitchell designed the first screw-pile lighthouse – his lighthouse
5457-533: The collapse of the Soviet government in 1990s, most of the official records on the locations, and condition, of these lighthouses were reportedly lost. Over time, the condition of RTGs in Russia degraded; many of them fell victim to vandalism and scrap metal thieves, who may not have been aware of the dangerous radioactive contents. Energy-efficient LED lights can be powered by solar panels , with batteries instead of
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#17327752769565564-488: The construction of lenses of large aperture and short focal length , without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. A Fresnel lens can also capture more oblique light from a light source, thus allowing the light from a lighthouse equipped with one to be visible over greater distances. The first Fresnel lens
5671-566: The crew has to rotate the entire vehicle if an enemy target presents itself outside of the vehicle's limited gun traverse arc. This can prove very disadvantageous in combat situations. During World War II , casemate-type armored fighting vehicles were heavily used by both the combined German Wehrmacht forces, and the Soviet Red Army . They were mainly employed as tank destroyers and assault guns . Tank destroyers, intended to operate mostly from defensive ambush operations, did not need
5778-408: The definition was widened to include a protected space for guns in a ship, either within the hull or in the lower part of the superstructure . Although the main armament of ships quickly began to be mounted in revolving gun turrets , secondary batteries continued to be mounted in casemates; however, several disadvantages eventually also led to their replacement by turrets. In tanks that do not have
5885-625: The development of the lighthouse. In antiquity, the lighthouse functioned more as an entrance marker to ports than as a warning signal for reefs and promontories , unlike many modern lighthouses. The most famous lighthouse structure from antiquity was the Pharos of Alexandria , Egypt , which collapsed following a series of earthquakes between 956 and 1323. The intact Tower of Hercules at A Coruña , Spain gives insight into ancient lighthouse construction; other evidence about lighthouses exists in depictions on coins and mosaics, of which many represent
5992-546: The early 1860s, the British, apprehensive about a possible French invasion , fortified the naval dockyards of southern England with curved batteries of large guns in casemates, fitted with laminated iron shields tested to withstand the latest projectiles. However, in the American Civil War (1861–1865), the exposed masonry of casemate batteries was found to be vulnerable to modern rifled artillery ; Fort Pulaski
6099-411: The edge of the cliff; due to the cumulative effects of shoreline erosion , it is now 100 feet (30 m) away from the edge. After World War II, the United States Army Corps of Engineers built a seawall at its base, but the erosion continued. The Coast Guard considered tearing down the lighthouse in 1967 and replacing it with a steel tower farther from the edge of the bluff. In the wake of protests over
6206-473: The emitted light into a concentrated beam, thereby greatly increasing the light's visibility. The ability to focus the light led to the first revolving lighthouse beams, where the light would appear to the mariners as a series of intermittent flashes. It also became possible to transmit complex signals using the light flashes. French physicist and engineer Augustin-Jean Fresnel developed the multi-part Fresnel lens for use in lighthouses. His design allowed for
6313-595: The end of World War II. The last ships built with casemates as new construction were the American Omaha -class cruisers of the early 1920s and the 1933 Swedish aircraft cruiser HSwMS Gotland . In both cases the casemates were built into the forward angles of the forward superstructure (and the aft superstructure as well, in the Omahas). In regards to armored fighting vehicles, casemate design refers to vehicles that have their main gun mounted directly within
6420-461: The end of the century, Imperial Germany had developed a new form of fortification called a feste ( German article: Festung#Feste ), in which the various elements of each fort were more widely dispersed in the landscape. These works, the first of which was Fort de Mutzig near Strasbourg , had separate artillery blocks, infantry positions and underground barracks, all built of reinforced concrete and connected by tunnels or entrenchments. Although
6527-412: The entrance into a harbor, such as New London Harbor Light . Where a tall cliff exists, a smaller structure may be placed on top such as at Horton Point Light . Sometimes, such a location can be too high, for example along the west coast of the United States, where frequent low clouds can obscure the light. In these cases, lighthouses are placed below the clifftop to ensure that they can still be seen at
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#17327752769566634-534: The erosion at Montauk would increase erosion at other Long Island beaches , as there are always related effects to such infrastructure work. On March 2, 2012, United States Secretary of the Interior Ken Salazar officially designated the lighthouse as a National Historic Landmark ; it is the 14th site on Long Island and the 11th lighthouse in the country to be so recognized. The United States Army Corps of Engineers announced on January 13, 2020,
6741-448: The gun except at the moment of firing. Casemates for secure barrack accommodation and storage continued to be built; the 1880s French forts of the Séré de Rivières system for example, had a central structure consisting of two stories of casemates, buried under layers of earth, concrete and sand to a depth of 18 metres (59 ft), intended to defeat the new high explosive shells. Towards
6848-592: The high-angle fire of mortars and howitzers . The advantages of casemated artillery were proved in the Crimean War of 1853–1856, when attempts by the Royal Navy to subdue the casemated Russian forts at Kronstadt were unsuccessful, while a casemated gun tower at Sevastopol , the Malakoff Tower , could only be captured by a surprise French infantry attack while the garrison was being changed. In
6955-400: The hull and lack the rotating turret commonly associated with tanks. Such a design generally makes the vehicle mechanically simpler in design, less costly in construction, lighter in weight and lower in profile. The saved weight can be used to mount a heavier, more powerful gun or alternatively increase the vehicle's armor protection in comparison to regular, turreted tanks. However, in combat
7062-399: The inner wall was part of the outer buildings of the settlement, and finally filled casemate walls, where the rooms between the walls were filled with soil right away, allowing for a quick, but nevertheless stable construction of particularly high walls. In fortifications designed to resist artillery, a casemate was originally a vaulted chamber usually constructed underneath the rampart . It
7169-455: The lantern room where the light operates. The lantern room is the glassed-in housing at the top of a lighthouse tower containing the lamp and lens. Its glass storm panes are supported by metal muntins (glazing bars) running vertically or diagonally. At the top of the lantern room is a stormproof ventilator designed to remove the smoke of the lamps and the heat that builds in the glass enclosure. A lightning rod and grounding system connected to
7276-535: The light is concentrated, if needed, by the "lens" or "optic". Power sources for lighthouses in the 20th–21st centuries vary. Originally lit by open fires and later candles, the Argand hollow wick lamp and parabolic reflector were introduced in the late 18th century. Whale oil was also used with wicks as the source of light. Kerosene became popular in the 1870s and electricity and acetylene gas derived on-site from calcium carbide began replacing kerosene around
7383-509: The lighthouse at Ostia . Coins from Alexandria, Ostia, and Laodicea in Syria also exist. The modern era of lighthouses began at the turn of the 18th century, as the number of lighthouses being constructed increased significantly due to much higher levels of transatlantic commerce. Advances in structural engineering and new and efficient lighting equipment allowed for the creation of larger and more powerful lighthouses, including ones exposed to
7490-469: The lighthouse keepers. Efficiently concentrating the light from a large omnidirectional light source requires a very large diameter lens. This would require a very thick and heavy lens if a conventional lens were used. The Fresnel lens (pronounced / f r eɪ ˈ n ɛ l / ) focused 85% of a lamp's light versus the 20% focused with the parabolic reflectors of the time. Its design enabled construction of lenses of large size and short focal length without
7597-470: The luminosity of traditional oil lights. The use of gas as illuminant became widely available with the invention of the Dalén light by Swedish engineer Gustaf Dalén . He used Agamassan (Aga), a substrate , to absorb the gas, allowing the gas to be stored, and hence used, safely. Dalén also invented the ' sun valve ', which automatically regulated the light and turned it off during the daytime. The technology
7704-475: The main armament of these forts was still mounted in armored turrets, local defense was provided by separate protected positions for field guns ; these concrete structures were copied by the French who called them casemates de Bourges ( French article: Casemate de Bourges ) after the proving ground where they had been tested. Following experience gained in the World War I , French engineers began to design
7811-518: The main deck, and later on the upper deck as well. Casemates on the main deck were very close to the waterline. In the Edgar -class cruisers, the guns in the casemates were only 10 feet (3.0 m) above the waterline. Casemates that were too close to the waterline or too close to the bow (such as in the 1912 Iron Duke -class dreadnoughts ) were prone to flooding, making the guns ineffective. Shipboard casemate guns were partially rendered obsolete by
7918-421: The metal cupola roof provides a safe conduit for any lightning strikes. Immediately beneath the lantern room is usually a Watch Room or Service Room where fuel and other supplies were kept and where the keeper prepared the lanterns for the night and often stood watch. The clockworks (for rotating the lenses) were also located there. On a lighthouse tower, an open platform called the gallery is often located outside
8025-496: The most impressive feats of engineering of the age. This structure was based upon Smeaton's design, but with several improved features, such as the incorporation of rotating lights, alternating between red and white. Stevenson worked for the Northern Lighthouse Board for nearly fifty years during which time he designed and oversaw the construction and later improvement of numerous lighthouses. He innovated in
8132-409: The new lantern; the current keeper's dwelling was constructed adjacent to the tower, and the original 1796 dwelling was demolished. A steam-powered fog signal was installed in 1873, with a fog signal building in 1897. The tower was originally all white; its single brown stripe was added in 1899. A fourth-order fixed red range-light was added to the watch deck of the tower in 1903 to warn of Shagwong Reef,
8239-402: The number of operational lighthouses has declined due to the expense of maintenance and the advent of much cheaper, more sophisticated, and more effective electronic navigational systems. Before the development of clearly defined ports , mariners were guided by fires built on hilltops. Since elevating the fire would improve visibility, placing the fire on a platform became a practice that led to
8346-608: The post-war period. Heavy casemate tank destroyer designs such as the US T28 and the British Tortoise never went beyond prototype status, while casemate vehicles of a more regular weight, such as the Soviet SU-122-54 , saw only very limited service. The general decline of casemate vehicles can be seen in the technological progress which resulted in the rise of universal main battle tanks , which unified in them
8453-656: The resistance of the outer wall against battering rams. Originally thought to have been introduced to the region by the Hittites , this has been disproved by the discovery of examples predating their arrival, the earliest being at Ti'inik (Taanach) where such a wall has been dated to the 16th century BC . Casemate walls became a common type of fortification in the Southern Levant between the Middle Bronze Age (MB) and Iron Age II, being more numerous during
8560-465: The sea. The function of lighthouses was gradually changed from indicating ports to the providing of a visible warning against shipping hazards, such as rocks or reefs. The Eddystone Rocks were a major shipwreck hazard for mariners sailing through the English Channel . The first lighthouse built there was an octagonal wooden structure, anchored by 12 iron stanchions secured in the rock, and
8667-451: The seabed and a low wooden structure is placed above the open framework, such as Thomas Point Shoal Lighthouse . As screw piles can be disrupted by ice, steel caisson lighthouses such as Orient Point Light are used in cold climates. Orient Long Beach Bar Light (Bug Light) is a blend of a screw pile light that was converted to a caisson light because of the threat of ice damage. Skeletal iron towers with screw-pile foundations were built on
8774-558: The sense of "false". However, it may have been ultimately derived from the Greek chásmata ( χάσματα ), a gap or aperture. The term casemate wall is used in the archaeology of Israel and the wider Near East , having the meaning of a double wall protecting a city or fortress, with transverse walls separating the space between the walls into chambers. These could be used as such, for storage or residential purposes, or could be filled with soil and rocks during siege in order to raise
8881-495: The siege of Atlanta, designed and built some of the most exotic lighthouses in the most difficult locations on the U.S. Great Lakes . French merchant navy officer Marius Michel Pasha built almost a hundred lighthouses along the coasts of the Ottoman Empire in a period of twenty years after the Crimean War (1853–1856). In a lighthouse, the source of light is called the "lamp" (whether electric or fuelled by oil) and
8988-545: The spring of 1943. Adjacent to the lighthouse, Camp Hero , opened by the Army in 1942, had two 16 inch gun batteries of two guns each, and a battery of two six-inch guns. The casemates , gun emplacements and concrete fire control towers (which are also at nearby Shadmoor State Park ) are still visible. In 1946, the United States Coast Guard took over maintenance of the lighthouse and operated it until
9095-486: The station was automated on February 3, 1987. In May of that year, the lighthouse museum opened to the public, operated by the Montauk Historical Society. It leased the property from the US Coast Guard for that purpose. On September 30, 1996, President Bill Clinton signed legislation transferring the lighthouse property to the Montauk Historical Society. The tower was built on Turtle Hill 300 feet (90 m) from
9202-528: The surface during periods of fog or low clouds, as at Point Reyes Lighthouse . Another example is in San Diego , California : the Old Point Loma lighthouse was too high up and often obscured by fog, so it was replaced in 1891 with a lower lighthouse, New Point Loma lighthouse . As technology advanced, prefabricated skeletal iron or steel structures tended to be used for lighthouses constructed in
9309-462: The tactical situation. The Wehrmacht employed several casemate tank destroyers, initially with the still- Panzerjäger designation Elefant with an added, fully enclosed five-sided (including its armored roof) casemate atop the hull, with later casemate-style tank destroyers bearing the Jagdpanzer (literally 'hunting tank') designation, with much more integration of the casemate's armour with
9416-702: The tank hull itself. Examples are the Jagdpanzer IV , the Jagdtiger and the Jagdpanther . Assault guns were designated as 'Sturmgeschütz', like the Sturmgeschütz III and Sturmgeschütz IV . In the Red Army, casemate tank destroyers and self-propelled guns bore an "SU-" or "ISU-" prefix, with the "SU-" prefix an abbreviation for Samokhodnaya Ustanovka , or "self-propelled gun". Examples are
9523-550: The term "casemate" has been used in a number of ways, but it generally refers to a protected space for guns within a ship's hull or superstructure. The first ironclad warship, the French ironclad Gloire (1858), was a wooden steamship whose hull was covered with armored plating, tested to withstand the largest smoothbore guns available at the time. The response by the British Royal Navy to this perceived threat
9630-432: The term referred to a vaulted chamber in a fort , which may have been used for storage, accommodation, or artillery which could fire through an opening or embrasure . Although the outward faces of brick or masonry casemates proved vulnerable to advances in artillery performance, the invention of reinforced concrete allowed newer designs to be produced well into the 20th century. With the introduction of ironclad warships,
9737-599: The third and most famous Eddystone Lighthouse , but some builders are well known for their work in building multiple lighthouses. The Stevenson family ( Robert , Alan , David , Thomas , David Alan , and Charles ) made lighthouse building a three-generation profession in Scotland. Richard Henry Brunton designed and built 26 Japanese lighthouses in Meiji Era Japan, which became known as Brunton's "children". Blind Irishman Alexander Mitchell invented and built
9844-486: The traditional light, including in some cases a rotating beam. A typical LED system designed to fit into the traditional 19th century Fresnel lens enclosure was developed by Trinity House and two other lighthouse authorities and costs about € 20,000, depending on configuration, according to a supplier; it has large fins to dissipate heat. Lifetime of the LED light source is 50,000 to 100,000 hours, compared to about 1,000 hours for
9951-480: The turn of the 20th century. Carbide was promoted by the Dalén light , which automatically lit the lamp at nightfall and extinguished it at dawn. In the second half of the 20th century, many remote lighthouses in Russia (then Soviet Union ) were powered by radioisotope thermoelectric generators (RTGs). These had the advantage of providing power day or night and did not need refuelling or maintenance. However, after
10058-613: The upper crest of the revetment. The project also included a complete repainting of the lighthouse. The total project cost $ 44 million. Pirate Captain Kidd was said to have buried treasure at the foot of the lighthouse site around 1699 at two ponds which today are called "Money Ponds." Notes Further reading Books by Henry Osmers, published by Outskirts Press: Lighthouse Lighthouses mark dangerous coastlines, hazardous shoals , reefs , rocks, and safe entries to harbors; they also assist in aerial navigation . Once widely used,
10165-535: The watch room (called the Main Gallery) or Lantern Room (Lantern Gallery). This was mainly used for cleaning the outside of the windows of the Lantern Room. Lighthouses near to each other that are similar in shape are often painted in a unique pattern so they can easily be recognized during daylight, a marking known as a daymark . The black and white barber pole spiral pattern of Cape Hatteras Lighthouse
10272-643: The weight and volume of material in conventional lens designs. Fresnel lighthouse lenses are ranked by order , a measure of refracting power, with a first order lens being the largest, most powerful and expensive; and a sixth order lens being the smallest. The order is based on the focal length of the lens. A first order lens has the longest focal length, with the sixth being the shortest. Coastal lighthouses generally use first, second, or third order lenses, while harbor lights and beacons use fourth, fifth, or sixth order lenses. Some lighthouses, such as those at Cape Race , Newfoundland, and Makapuu Point , Hawaii, used
10379-437: Was a kerosene lamp or, earlier, an animal or vegetable oil Argand lamp, and the lenses rotated by a weight driven clockwork assembly wound by lighthouse keepers, sometimes as often as every two hours. The lens assembly sometimes floated in liquid mercury to reduce friction. In more modern lighthouses, electric lights and motor drives were used, generally powered by diesel electric generators. These also supplied electricity for
10486-410: Was breached in a few hours by only ten such guns. In contrast, hastily constructed earthworks proved much more resilient. This led to casemates for artillery again falling out of favor. In continental Europe, they were often replaced by rotating gun turrets, but elsewhere large coastal guns were mounted in less expensive concrete gun pits or barbettes , sometimes using disappearing carriages to conceal
10593-459: Was built by Henry Winstanley from 1696 to 1698. His lighthouse was the first tower in the world to have been fully exposed to the open sea. The civil engineer John Smeaton rebuilt the lighthouse from 1756 to 1759; his tower marked a major step forward in the design of lighthouses and remained in use until 1877. He modeled the shape of his lighthouse on that of an oak tree , using granite blocks. He rediscovered and used " hydraulic lime ",
10700-683: Was built on piles that were screwed into the sandy or muddy seabed. Construction of his design began in 1838 at the mouth of the Thames and was known as the Maplin Sands lighthouse, and first lit in 1841. Although its construction began later, the Wyre Light in Fleetwood, Lancashire, was the first to be lit (in 1840). Until 1782 the source of illumination had generally been wood pyres or burning coal. The Argand lamp , invented in 1782 by
10807-585: Was commissioned to build a fort on the Île-d'Aix , defending the port of Rochefort, Charente-Maritime . The outbreak of the Anglo-French War forced him to hastily to build his casemated fort from wood but he was able to prove that his well-designed casemates were capable of operating without choking the gunners with smoke. The defenses of the new naval base at Cherbourg were later constructed according to his system. After seeing Montalembert's coastal forts, American engineer Jonathan Williams acquired
10914-418: Was intended to be impenetrable and could be used for sheltering troops or stores. With the addition of an embrasure through the scarp face of the rampart, it could be used as a protected gun position. In bastion forts , artillery casemates were sometimes built into the flanks of bastions , but in action they quickly filled with smoke making them inoperable and for that reason, had fallen out of favor during
11021-475: Was opposed by a local surfing group, who contended that a seawall would ruin the nearby world-renowned surf break . They proposed moving the lighthouse back from the shore, as was done with the Cape Hatteras Lighthouse . Complicating such a move is the terrain, which would require the lighthouse to be moved down one hill and up another. Environmental groups have raised concerns that reducing
11128-474: Was the first lighthouse in New York State, and is the fourth-oldest active lighthouse in the United States. The tower is 110 feet 6 inches (33.68 metres) high. The current light is a 3 1 ⁄ 2 order bivalve (clamshell) Fresnel lens. On April 12, 1792, construction on the lighthouse was authorized by the 2nd United States Congress under President George Washington . Ezra L'Hommedieu ,
11235-506: Was the predominant light source in lighthouses from the 1900s to the 1960s, when electric lighting had become dominant. With the development of the steady illumination of the Argand lamp, the application of optical lenses to increase and focus the light intensity became a practical possibility. William Hutchinson developed the first practical optical system in 1777, known as a catoptric system. This rudimentary system effectively collimated
11342-411: Was to build an iron-hulled frigate, HMS Warrior (1860) . However, it was realised that to armor all of the hull to fully withstand the latest rifled artillery would make it unfeasibly heavy, so it was decided to create an armored box or casemate around the main gun deck, leaving the bow and stern unarmored. The American Civil War saw the use of casemate ironclads : armored steamboats with
11449-598: Was used in 1823 in the Cordouan lighthouse at the mouth of the Gironde estuary ; its light could be seen from more than 20 miles (32 km) out. Fresnel's invention increased the luminosity of the lighthouse lamp by a factor of four and his system is still in common use. The introduction of electrification and automatic lamp changers began to make lighthouse keepers obsolete. For many years, lighthouses still had keepers, partly because lighthouse keepers could serve as
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