Lattice mast

Lattice masts, or cage masts, are a type of observation mast common on major warships in the early 20th century. They are a type of hyperboloid structure, whose weight-saving design was invented by the Russian engineer Vladimir Shukhov. They were used most prominently on American dreadnought battleships and armored cruisers of the World War I era.

In the age of sail masts were required to support the sails, and lookouts were posted on them; with the advent of engine-powered warships masts were retained and used for observation and to spot fall of shot. The purpose of the lattice structure was to make the posts less vulnerable to shells from enemy ships, and to better absorb the shock caused by firing heavy guns, isolating the delicate fire control equipment (rangefinders, etc.) mounted on the mast tops. However, the masts were found to be easily damaged by the inclement weather experienced at sea by naval ships during typhoons and hurricanes: the USS Michigan's mast was bent right down to the deck by such a storm in 1918. As the caliber and range of ships' guns increased, heavier rangefinders were required, and the powerful guns and engines created shock and vibrations; lattice masts were phased out in favor of more rigid tripod masts.

Uss south carolina bb
USS South Carolina, the first American battleship with lattice masts.

Use in the United States Navy

The South Carolina-class battleships were the first class of American battleships to feature lattice masts,[1] which were to become a standard fixture on all American battleships, and many cruiser classes.[2] Older vessels, including the first modern American battleship, Indiana, were modernized with lattice masts during the period.[3]

In January 1918, the lattice mast of the battleship USS Michigan collapsed in a severe storm; the heavy seas put excessive stress on the mast and the weight of the fire control equipment caused the mast to fail at the narrowest point. The incident spurred an investigation by the Bureau of Construction and Repair, which found that the collapse was in part due to the fact that the mast had been lengthened, with a new section spliced in where the mast broke. In addition, fragments from a recent explosion in one of the ship's 12-inch (300 mm) guns had damaged the mast, and the damage had not been adequately repaired. Nevertheless, the investigation also found that the mast aboard the battleship Connecticut also showed signs of buckling. Throughout the 1920s and 1930s, the Navy repeatedly found evidence of structural problems in the masts, in large part due to the corrosive effects of funnel gases.[4]

At the same time as the Michigan incident, US Navy officers were also gaining experience with British tripod masts for the first time while serving with the Grand Fleet during World War I. Unlike lattice masts, the heavier tripods did not suffer from vibration when steaming at high speed, and they were not as susceptible to shock from gunfire,[4] which caused the lattice masts to whip from the concussion.[5]

All American battleships, up to the Colorado-class battleships were equipped with lattice masts, although in the 1920s to 1930s, the older battleships had their lattice masts replaced with more modern tripod masts, concomitant with the addition of larger, much heavier fire-control director tops.[6] The newer Tennessee and Colorado classes retained their original lattice masts, of heavier construction than those on earlier ships, at the start of World War II.

Use in other navies

Only four battleships were completed with lattice masts for other navies. The two Andrei Pervozvanny-class battleships of the Imperial Russian Navy had lattice masts until they were replaced with conventional masts in the beginning of the First World War.[7] The two United States-built Rivadavia-class battleships of the Argentine Navy, ARA Rivadavia and ARA Moreno, had lattice masts. They were the only dreadnought-type battleships built for export by the USA.[8] Two other battleships, the US pre-dreadnoughts Mississippi and Idaho were sold to Greece in 1914; they retained their lattice masts until their sinking by the Germans in 1941.

Some navies considered lattice masts for their ships. Following their experience with the Andrei Pervozvannys, the Russians initially designed the four Gangut-class battleships with lattice masts, but constructed with pole ones.[9][10] The German Imperial Navy designed its first battlecruiser, SMS Von der Tann, with lattice masts, but she was instead completed with pole masts.[11]

Use in fortifications

A lattice fire-control mast was installed on Fort Drum, a fort built by the United States to guard the entrance of Manila Bay. The mast directed the fire of the fort's 14-inch main batteries.[12]

Notes

  1. ^ Hore, p. 56
  2. ^ Hore, pp. 56–60
  3. ^ Friedman, p. 27
  4. ^ a b Friedman, p. 177
  5. ^ Friedman, p. 195
  6. ^ Hore, p. 60
  7. ^ Morison, Morison and Polmar, p. 172.: Quote:"The only foreign ships to have them were the U.S.-built Argentinian Rivadavia and Moreno and the Russian Andrei Pervozvanny and Imperator Pavel I."
  8. ^ Hore, p. 91
  9. ^ Hythe, pp. 351-352 (Plates 57-58)
  10. ^ Melnikov, p. 24
  11. ^ Staff, p. 8
  12. ^ McGovern, pp. 14-15

References

  • Friedman, Norman (1985). U.S. Battleships: An Illustrated Design History. Annapolis, Maryland: Naval Institute Press. ISBN 978-0-87021-715-9. OCLC 12214729.
  • Hore, Peter (2006). Battleships of World War I. London: Southwater Books. ISBN 978-1-84476-377-1.
  • Morison, S. L.; Morison, S. E.; Polmar, N. (2003). The American Battleship. Zenith. ISBN 0-7603-0989-2.
  • Hythe, Thomas A., ed. (1912). The Naval Annual. (Brassey's Naval Annual). Portsmouth: J. Griffin & Co.
  • Melnikov, R. M. (2003). (in Russian) Lineyny korabl "Andrey Pervozvanny" (1906–1925) (Линейный корабль "Андрей Первозванный" (1906–1925)). Saint Petersburg: Korabli i srazheniya. (no ISBN).
  • McGovern, Terrance C. (2003). American Defenses of Corregidor and Manila Bay 1898-1945. Osprey. ISBN 1-84176-427-2.
  • Staff, Gary (2006). German Battlecruisers: 1914–1918. Oxford: Osprey Books. ISBN 978-1-84603-009-3.
Angus transmitting station

The Angus transmitting station is a broadcasting and telecommunications facility, situated approximately five miles due north of the city of Dundee, approximately between the villages of Charleston and Tealing, Scotland (grid reference NO394407). It includes a guyed steel lattice mast which is 229.5 metres (753 ft) [1] in height. Mounted at the top are the UHF television antennas, contained within a GRP shroud. These antennas have an average height above Ordnance Datum of 547 metres (1,795 ft).[2]. It is owned and operated by Arqiva.

Black Mountain transmitting station

The Black Mountain transmitting station is a broadcasting and telecommunications facility, situated on land 301 metres (988 ft) above Ordnance Datum (mean sea level) to the west of the city of Belfast, in Northern Ireland (grid reference J278727). It includes a guyed steel lattice mast which is 228.6 metres (750 ft) [1] in height. The height of the top of the structure above mean sea level is 529 metres (1,736 ft). It is owned and operated by Arqiva.

Caldbeck transmitting station

The Caldbeck transmitting station is a broadcasting and telecommunications facility, situated close to the village of Caldbeck, in Cumbria, England (Grid Reference: NY299425). It is owned and operated by Arqiva.

It includes a 337-metre-high (1,106 ft) guyed steel lattice mast, which is the third highest structure in the United Kingdom. The transmission antennas surmounting the structure are contained within a fibreglass cylinder.

Chillerton Down transmitting station

The Chillerton Down transmitting station is a broadcasting facility for FM and DAB radio at Chillerton Down, above the village of Chillerton on the Isle of Wight off the south coast of England (grid reference SZ475835). The transmitter was erected in 1958 and uses a 228.9-metre (751 ft) high guyed steel lattice mast of triangular cross section as an aerial.It was originally used to transmit Southern Television, and later TVS, until the end of VHF television transmissions in the UK at the beginning of 1985. It now transmits Wave 105, 103.2 Capital FM, Sam FM, Isle of Wight Radio, the local Arqiva (NOW S. Hampshire) DAB multiplex and the national Digital One DAB multiplex.

The site is owned and operated by Arqiva.

Dover transmitting station

The Dover transmitting station is a facility for broadcasting and telecommunications, located at West Hougham, near Dover, Kent (grid reference TR274397). It has a 243.2 metres (798 ft) high guyed steel lattice mast of triangular cross section. The station is owned by Arqiva. The recommended UHF aerial group is C/D with horizontal polarisation.

There is also a relay transmitter located in the town of Dover (Dover Town); in addition FM radio services are covered by the Swingate transmitting station.

Along with Heathfield and Bluebell Hill, Dover transmits regional television services from BBC One South East and ITV Meridian (South East).

Durris transmitting station

The Durris transmitting station is a broadcasting and telecommunications facility, situated close to the town of Stonehaven, within Durris Forest, within the area also known historically as Kincardineshire (grid reference NO763899). It is owned and operated by Arqiva.

It has a 306.6 metres (1,006 ft) high guyed steel lattice mast. The analogue television transmission antennas surmounting the structure are contained within a GRP cylinder, and bring the overall height of the structure to 322.0 metres (1,056 ft), making it the tallest structure in Scotland. It was constructed in 1961 and coverage includes north east Scotland, from St. Andrews in the south to Fraserburgh in the north, including the city of Aberdeen. It also covers much of the North Sea coast between Dunbar and Berwick, although this coverage is not deliberate.

It is also a feature in Durris Primary's newest logo created in 2000 (the logo shows the mast on the hill with the sun and three trees).

It can be seen from the summit of Mither Tap, near Insch, Aberdeenshire and can also be spotted at night on the road down from the Lecht Ski Centre.

Hannington transmitting station

Hannington transmitting station is a television and radio transmitting station located on Cottington Hill near the village of Hannington. The transmitter is actually in the parish of Kingsclere. The station provides broadcast services to Berkshire and north Hampshire, and includes a 131.4 metres (431 ft) guyed steel lattice mast. Surmounting the mast is a GRP aerial cylinder, which contains the UHF television transmitting antennas, which brings the overall height of the mast to 151.9 metres (498 ft).

Hannington's digital broadcasts were severely attenuated to the East before DSO (Digital Switch-Over) so as not to cause co-channel interference with Guildford transmitter. Those restrictions were removed soon after DSO in 2012. see picture.

List of catastrophic collapses of broadcast masts and towers

This is a list of catastrophic collapses of masts and towers.

Masts and towers can collapse as a result of natural disasters, such as storms and fires; from engineering defects; and from accidents or sabotage.

List of tallest structures in the United Kingdom

This list contains all types of structures, 150 metres (490 ft) in height or more, which is the accepted criterion for a building to qualify as a skyscraper in the United Kingdom.

Entries in italics denote approximate figures.

Longwave

In radio, longwave, long wave or long-wave, and commonly abbreviated LW, refers to parts of the radio spectrum with wavelengths longer than what was originally called the medium-wave broadcasting band. The term is historic, dating from the early 20th century, when the radio spectrum was considered to consist of longwave (LW), medium-wave (MW), and short-wave (SW) radio bands. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short'.

In contemporary usage, the term longwave is not defined precisely, and its intended meaning varies. It may be used for radio wavelengths longer than 1,000 m i.e. frequencies up to 300 kilohertz (kHz), including the International Telecommunications Union's (ITU's) low frequency (LF, 30–300 kHz) and very low frequency (VLF, 3–30 kHz) bands. Sometimes the upper limit is taken to be higher than 300 kHz, but not above the start of the medium wave broadcast band at 525 kHz.In Europe, Africa, and large parts of Asia (International Telecommunication Union Region 1), where a range of frequencies between 148.5 and 283.5 kHz is used for AM broadcasting in addition to the medium-wave band, the term longwave usually refers specifically to this broadcasting band, which falls wholly within the low frequency band of the radio spectrum (30–300 kHz). The "Longwave Club of America" (United States) is interested in "frequencies below the AM broadcast band" (i.e., all frequencies below 525 kHz).

Midhurst transmitting station

The Midhurst transmitting station is a facility for both analogue and digital VHF/FM radio and UHF television transmission, 3.1 miles (5.0 km) northeast of Midhurst, West Sussex, England.

It includes a guyed steel lattice mast, and on top of this is the UHF television transmitting antenna, which brings the overall height of the structure to 117.7 metres (386 ft).

The transmission site is located at 51° 01′ 2.0″ North, 0° 42' 4.0" West (National Grid Reference: SU912250).

The current mast has an average height of 307 metres above sea level. It is now owned and operated by Arqiva, but was owned by the BBC before they privatised their transmission department prior to 1997.

Mounteagle transmitting station

The Mounteagle transmitting station is a broadcasting and telecommunications facility, situated close to the town of Fortrose, Scotland, in Highland (grid reference NH639580). It includes a 243.8 metres (800 ft) high guyed steel lattice mast. It is owned and operated by Arqiva.

Peterborough transmitting station

The Peterborough transmitting station is a broadcasting and telecommunications facility at Morborne Hill, near Peterborough, (grid reference TL127913).

There are two tall structures on adjacent sites: a guyed steel lattice mast belonging to Arqiva, and a 98.45 metres tall reinforced concrete tower belonging to BT. These sites are known by their owners as 'Peterborough' and 'Morborne Hill' respectively.

Rumster Forest transmitting station

The Rumster Forest transmitting station is a broadcasting and telecommunications facility near the town of Wick, in Caithness, Scotland (grid reference ND197385). It is owned and operated by Arqiva.

It has a 229.2 metres (752 ft) high guyed steel lattice mast. It was constructed in 1965 and coverage includes north west Scotland, including Caithness and parts of eastern Sutherland. It also serves coastal areas of Moray and Banffshire.

It carries six digital TV multiplexes. It also carries national analogue BBC FM radio, including BBC Radio 1, BBC Radio 2, BBC Radio 3, BBC Radio 4 and BBC Radio Scotland.

Selkirk transmitting station

The Selkirk transmitting station is a telecommunications facility located next to Lindean Loch, near Selkirk in the Scottish Borders. It includes a 229.1 metres (752 ft) high guyed steel lattice mast, surmounted by a UHF television transmitting antenna array, which brings the overall height of the structure to 238.8 metres (783 ft). It is owned and operated by Arqiva.

Skelton Transmitting Station

The Skelton Transmitting Station is a radio transmitter site at grid reference NY433376 near Skelton, Cumbria, England about 5 miles (8 km) north west of Penrith, run by Babcock International and owned by the MOD. Since the Belmont Mast was shortened in 2010, the mast at Skelton has been the tallest structure in the United Kingdom.In 1946, the BBC was heralding the site as being "the World's largest and most powerful (shortwave) radio station".The main purpose of it is shortwave broadcasting. The site is capable of DRM on at least 3955 kHz and 3975 kHz (75m broadcast band) beamed at 121° towards Germany and Central Europe. On AM the frequencies of 5995 kHz and 6195 kHz (49m broadcast band) and 9410 kHz (31m broadcast band) and 12095 kHz (25m broadcast band) are known.A VLF transmitter is also located there. It is used to transmit coded orders to submarines. It uses as its aerial a 365 metre (1,198 foot) high guyed steel lattice mast, which is insulated against ground and is the tallest structure in the UK. The transmitter went into service in 2001 and is the successor to the GBR transmitter at Rugby Radio Station.

Strabane transmitting station

The Strabane transmitting station is a broadcasting and telecommunications facility located at Legfordrum and situated very close to the town of Strabane, in County Tyrone, Northern Ireland (Grid Reference: H393947, GNR: IH393947). It is owned and operated by Arqiva.

It includes a 305.5 metres (1,002 ft) high guyed steel lattice mast, which is the tallest structure in Ireland. The transmission antennas surmounting the structure are contained within a fibreglass cylinder. Constructed in 1963, it came into service on 18 February of that year.

Tacolneston transmitting station

The Tacolneston transmitting station is a facility for both analogue and digital VHF/FM radio and UHF television transmission near Tacolneston, 11 miles (18 km) south-west of Norwich, Norfolk, England.

It includes a 149.0 metres (489 ft) tall guyed steel lattice mast, which was built in 1956 (completed in late September/early October that year). On top of the mast is located the UHF television transmitting antenna, which brings the overall height of the structure to 165.0 metres (541 ft).

Tripod mast

The tripod mast is a type of mast used on warships from the Edwardian era onwards, replacing the pole and lattice mast. Tripod masts are notable for using three large (usually cylindrical) support columns spread out at angles to brace each other.

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