A fog bell is a navigation mark used as an audible aid to navigation in seafaring, especially in fog and poor visibility. Floating navigation signs with bells are called bell buoys. On ships, the ship's bell is used for sound signals. Due to more suitable sound generators, but also the development and spread of radar, satellite navigation and electronic charting systems, fog bells have lost their importance for maritime navigation.
Starting in the 18th century, fog signals were given for seafaring in Europe, initially cannons or guns. [1] In 1766, the first bell for this purpose was installed in Nidingen on the Baltic Sea. [2] These were initially rung by hand, which was a chore during prolonged fog, [1] others used mechanisms similar to clockwork that had to be wound periodically. [2] Andrew Morse Jr. eventually developed a "perpetual fog bell" that was used in 1839 at Penobscot Bay. [1] [3] It consisted of a long wooden beam that moved up and down with the waves, moving weights upward that struck the bell in the downward motion. However, the float was easily swept away by the sea. Subsequently, other mechanisms were developed, often either attached to light towers or housed in their own bell towers. [1] [2]
In 1878, there were 93 fog bells in the USA. However, the bells had the problem of low range, especially in windy conditions. [1] [2] In England, most mechanical fog bells were decommissioned around 1905, in the United States in the 1960s. [2] Most bells have since been replaced by much louder foghorns.
Occasionally, fog bells also served for orientation on land, for example, the bell "Maria" helped hikers on the inhospitable plateaus in the Aubrac to find the Hospital of Aubrac in France.
A bell buoy is a floating sea mark with a bell that is made to sound by the swell. It belongs to the sound buoys and by shape to the beacon buoys. [5] [6] In nautical charts, bell buoys are designated Bell. The development of these floating sea marks dates back to the 19th century. Initially, small boats were fitted with bells and anchored. The first true bell buoy was developed in 1852 by Lieutenant Brown, who worked at the Lighthouse Establishment. He took a buoy and constructed a mount for the bell, under which he placed a plate with radial grooves on which a cannonball rolled and, moved by the swell, struck the bell. [7] A bell buoy was first used in 1855. [8] Today's bell barrels usually have several movable mallets attached to the outside of the bell. [7]
Thus, these sound buoys were in use before the light buoys, which were produced from 1876. The same purpose as bell buoys is served by the whistle buoys invented in 1876, as well as gong buoys, invented in 1921. The latter have three or four flat bells mounted vertically above each other with different pitches, making them acoustically distinguishable from single bells. They are used exclusively in the United States and are listed on nautical charts with the label Gong. [9] [10] Experiments during this period to strike the bells electrically or to replace them outright with electric signaling systems were unsuccessful because the electronics were disturbed by swell and salt water. [7]
Bell buoys are usually made to ring irregularly by the swell and then have no fixed characteristic. Only occasionally are special striking mechanisms with regular chimes used. [5] Sound buoys are mainly suitable as safe water marks for the entrances of nautical channels from the sea. [11] The last bell buoy of the Weser district was moved to the German Maritime Museum in Bremerhaven in 2006. [12] In the Kiel Fjord there is a bell buoy off Laboe at a shoal.
Experiments with bells underwater were first undertaken in 1826 in Lake Geneva by Charles-François Sturm and Jean-Daniel Colladon to determine the speed of sound. In the late 19th century, bells began to be installed on lightvessels below the surface of the water, the sound of which was received by ships in the fog using stethoscopes or microphones. This development of submarine signals was spurred in 1901 by the founding of the Submarine Signal Co. in Boston and the development of hydrophones by Elisha Gray, among others. The advantage is that sound propagation under water is much straighter than in air, making location more accurate. However, the bells were soon replaced by electric transducers, and the ideas of subsurface sound generation and detection were used by Reginald Fessenden to develop sonars. [13] [14] [15] [16] [17]
In the free nautical chart OpenSeaMap, 120 seamarks with bells as fog signals have been entered by volunteers, compared to 11 gongs, 84 whistles, and 581 foghorns (as of September 2021). [18] However, these figures are incomplete and at best are only suitable for comparing the significance of the individual sound signals with each other.
The British writer Rudyard Kipling (1865-1936) wrote the poem The Bell Buoy, in which the bell on a bell buoy on a shoal compares itself to a church bell and decides it does not want to "change with my brother a league inland". The church bell, controlled by the authority of the church, would have to fight with "darkling Powers" instead of independently doing its vital work and struggling with the darkling sea. [19]
In the poem "The Dry Salvages", T.S. Eliot references fog bells several times, in keeping with the varied nautical images used throughout the poem. In Part 1, Eliot references a bell which "measures time not our time...a time older than the time of chronometers" rung by the swelling of the ocean which "is and was from the beginning". In Part II, Eliot again references the "undeniable clamour of the bell of the last annunciation" heard by unidentified mariners as their boat drifts, slowly leaking. Finally, in Part IV, a prayer to the Blessed Virgin Mary, Eliot likens a fog bell to a "perpetual Angelus". [20]
A buoy is a floating device that can have many purposes. It can be anchored (stationary) or allowed to drift with ocean currents.
The history of the many lightvessel stations of Great Britain goes back over 250 years to the placement of the world's first lightship at the Nore in the early 18th century.
A sea mark, also seamark and navigation mark, is a form of aid to navigation and pilotage that identifies the approximate position of a maritime channel, hazard, or administrative area to allow boats, ships, and seaplanes to navigate safely.
The Nab Tower was a tower planned for anti-submarine protection in the Solent in World War I. It was sunk over the Nab rocks east of the Isle of Wight to replace a lightship after the war, and is a well-known landmark for sailors as it marks the deep-water eastern entry into the Solent.
A foghorn or fog signal is a device that uses sound to warn vehicles of navigational hazards such as rocky coastlines, or boats of the presence of other vessels, in foggy conditions. The term is most often used in relation to marine transport. When visual navigation aids such as lighthouses are obscured, foghorns provide an audible warning of rock outcrops, shoals, headlands, or other dangers to shipping.
Radar beacon is – according to article 1.103 of the International Telecommunication Union's (ITU) ITU Radio Regulations (RR) – defined as "A transmitter-receiver associated with a fixed navigational mark which, when triggered by a radar, automatically returns a distinctive signal which can appear on the display of the triggering radar, providing range, bearing and identification information." Each station shall be classified by the service in which it operates permanently or temporarily.
The United States Lighthouse Board was the second agency of the U.S. federal government, under the Department of Treasury, responsible for the construction and maintenance of all lighthouses and navigation aids in the United States, between 1852 and 1910. The new agency was created following complaints of the shipping industry of the previous administration of lighthouses under the Treasury's Lighthouse Establishment, which had had jurisdiction since 1791, and since 1820, been under the control of Stephen Pleasonton.
A navigational aid (NAVAID), also known as aid to navigation (ATON), is any sort of signal, markers or guidance equipment which aids the traveler in navigation, usually nautical or aviation travel. Common types of such aids include lighthouses, buoys, fog signals, and day beacons.
Stratford Shoal Light, officially Stratford Shoal Light, is a lighthouse on a shoal in the middle of Long Island Sound approximately halfway between Port Jefferson, New York and Bridgeport, Connecticut.
Nautical publications is a technical term used in maritime circles describing a set of publications, either published by national governments or by commercial and professional organisations, for use in safe navigation of ships, boats, and similar vessels. Other publications might cover topics such as seamanship and cargo operations. In the UK, the United Kingdom Hydrographic Office, the Witherby Publishing Group and the Nautical Institute provide numerous navigational publications, including charts, publications on how to navigate and passage planning publications. In the US, publications are issued by the US government and US Coast Guard.
The Needles Lighthouse is an active 19th century lighthouse on the outermost of the chalk rocks at The Needles on the Isle of Wight in the United Kingdom, near sea level. Designed by James Walker, for Trinity House at a cost of £20,000. It was completed in 1859 from granite blocks, stands 33.25 metres (109.1 ft) high and is a circular tower with straight sides. It replaced an earlier light tower on top of a cliff overhanging Scratchell's Bay, which was first lit on 29 September 1786.
Lowestoft Lighthouse is a lighthouse operated by Trinity House located to the north of the centre of Lowestoft in the English county of Suffolk. It stands on the North Sea coast close to Ness Point, the most easterly point in the United Kingdom. It acts as a warning light for shipping passing along the east coast and is the most easterly lighthouse in the UK.
Dungeness Lighthouse on the Dungeness Headland started operation on 20 November 1961. Its construction was prompted by the building of Dungeness nuclear power station, which obscured the light of its predecessor which, though decommissioned, remains standing. The new lighthouse is constructed of precast concrete rings; its pattern of black and white bands is impregnated into the concrete. It remains in use today, monitored and controlled from the Trinity House Operations and Planning Centre at Harwich, Essex.
The North Bull Lighthouse, is an active aid to navigation located at the mouth of the River Liffey, near Dublin, Ireland. It is one of four lighthouses that help guide shipping into the Liffey, and the Port of Dublin, all of which are operated and maintained by the Dublin Port Company.
Radio acoustic ranging, occasionally written as "radio-acoustic ranging" and sometimes abbreviated RAR, was a method for determining a ship's precise location at sea by detonating an explosive charge underwater near the ship, detecting the arrival of the underwater sound waves at remote locations, and radioing the time of arrival of the sound waves at the remote stations to the ship, allowing the ship's crew to use true range multilateration to determine the ship's position. Developed by the United States Coast and Geodetic Survey in 1923 and 1924 for use in accurately fixing the position of survey ships during hydrographic survey operations, it was the first navigation technique in human history other than dead reckoning that did not require visual observation of a landmark, marker, light, or celestial body, and the first non-visual means to provide precise positions. First employed operationally in 1924, radio acoustic ranging remained in use until 1944, when new radio navigation techniques developed during World War II rendered it obsolete.
Submarine signals had a specific, even proprietary, meaning in the early 20th century. It applied to a navigation aid system developed, patented and produced by the Submarine Signal Company of Boston. The company produced submarine acoustic signals, first bells and receivers then transducers, as aids to navigation. The signals were fixed, associated with lights and other fixed aids, or installed aboard ships enabling warning of fixed hazards or signaling between ships. ATLAS-Werke, at the time Norddeutsche Maschinen und Armaturenfabrik, of Germany also manufactured the equipment under license largely for the European market.
