Mooring mast
Encyclopedia
A mooring mast, or mooring tower, is a structure designed to allow for the docking of an airship
outside of an airship hangar
or similar structure. More specifically, a mooring mast is a mast or tower that contains a fitting on its top that allows for the bow
of the airship to attach its mooring line to the structure.
When it is not necessary or convenient to put an airship
into its hangar
(or shed
) between flights, airships can be moored on the surface of land or water, in the air to one or more wires, or to a mooring mast. After their development mooring masts became the standard approach to mooring airships as considerable manhandling was avoided.
which was originally constructed to serve as a mooring mast, although soon after converted for use as a television tower due to the discovered infeasibility of mooring an airship, for any length of time, to a very tall mast in the middle of an urban area.
_-1911.jpg)
, named the ‘Mayfly’, on 22 May 1911. The 38 ft (11.6 m) mast was mounted on a pontoon, and a windbreak of cross-yards with strips of canvas were attached to it. However, the windbreak caused the ship to yaw badly, and she became more stable when it was removed, withstanding winds gusting up to 43 miles per hour (19.2 m/s) . Further experiments in mooring blimp
s to cable-stayed lattice masts were carried out during 1918 .
and Cardington
in 1919-21 to make the landing process easier and more economical of manpower
The following account of the British high mast in its fully developed state at Cardington
, and its operation, is abridged from Masefield.
Four high masts of the Cardington type were built along the proposed British Empire Airship Service routes, at Cardington itself, at Montreal
(Canada), Ismailia
(Egypt
) and Karachi
(then India, now in Pakistan). None of these survive. Similar masts were proposed at sites in Australia, Ceylon (now Sri Lanka
), Bombay, Keeling Islands, Kenya
, Malta
, at Ohakea in New Zealand, and in South Africa . The general site specifications can be found in documents produced by the British government.
The following account of landing the German airship Graf Zeppelin
is abridged from Dick and Robinson (1985) :
Dick states that the Germans never used mooring masts until the Graf Zeppelin entered service in 1928, and never moored to high masts. To some extent this probably reflects the conservatism of the Zeppelin company operations. Long experience in handling airships in all sorts of conditions was valued and innovations or significant changes in practice were unlikely to be adopted unless clear advantages were apparent.
Being part of a ground crew was not risk-free. In gusty conditions, or if mis-handled, an airship could suddenly rise. If the ground crew did not immediately let go of the handling lines they risked being carried off their feet. In one famous incident captured on movie film in 1932, during the landing of the US airship Akron
, three men were carried off their feet in this way, two to fall to their deaths after a short time. The third managed to improve his hold on the handling rope until he could be hauled into the airship .
At least two ships have mounted mooring masts. As the US intended to use large airships for long-range maritime patrol operations experiments were made in mooring airships to a mast mounted on the ship USS Patoka.
Over time the airships , , and all moored to the mast mounted at the stern of the ship, and operated using her as a base for resupply, refuelling and gassing.
The Spanish seaplane carrier Dédalo
(1922–1935) carried a mooring mast at the bow to cater for small dirigibles carried on board.
Airship
An airship or dirigible is a type of aerostat or "lighter-than-air aircraft" that can be steered and propelled through the air using rudders and propellers or other thrust mechanisms...
outside of an airship hangar
Airship hangar
Airships are sheltered in airship hangars during construction and sometimes also for regular operation, particularly at bad weather conditions. Rigid airships always needed to be based in airship hangars because weathering was a serious risk.- History :...
or similar structure. More specifically, a mooring mast is a mast or tower that contains a fitting on its top that allows for the bow
Bow (ship)
The bow is a nautical term that refers to the forward part of the hull of a ship or boat, the point that is most forward when the vessel is underway. Both of the adjectives fore and forward mean towards the bow...
of the airship to attach its mooring line to the structure.
When it is not necessary or convenient to put an airship
Airship
An airship or dirigible is a type of aerostat or "lighter-than-air aircraft" that can be steered and propelled through the air using rudders and propellers or other thrust mechanisms...
into its hangar
Hangar
A hangar is a closed structure to hold aircraft or spacecraft in protective storage. Most hangars are built of metal, but other materials such as wood and concrete are also sometimes used...
(or shed
Shed
A shed is typically a simple, single-storey structure in a back garden or on an allotment that is used for storage, hobbies, or as a workshop....
) between flights, airships can be moored on the surface of land or water, in the air to one or more wires, or to a mooring mast. After their development mooring masts became the standard approach to mooring airships as considerable manhandling was avoided.
Mast types
Airship mooring masts can be broadly divided into fixed high masts and fixed or mobile low (or ‘stub’) masts. In the 1920s and 1930s masts were built in many countries. At least two were mounted on ships. Without doubt the tallest mooring mast ever designed was the spire of the Empire State BuildingEmpire State Building
The Empire State Building is a 102-story landmark skyscraper and American cultural icon in New York City at the intersection of Fifth Avenue and West 34th Street. It has a roof height of 1,250 feet , and with its antenna spire included, it stands a total of 1,454 ft high. Its name is derived...
which was originally constructed to serve as a mooring mast, although soon after converted for use as a television tower due to the discovered infeasibility of mooring an airship, for any length of time, to a very tall mast in the middle of an urban area.
Early developments
Mooring an airship by the nose to the top of a mast or tower of some kind might appear to be an obvious solution, but dirigibles had been flying for some years before the mooring mast made its appearance. The first airship known to have been moored to a mast was HMA (His Majesty's Airship) No.1HMA No. 1
His Majesty's Airship No. 1, more commonly known as the Mayfly, was designed and built by Vickers, Sons and Maxim at their works in Barrow-in-Furness, Cumbria, England, as an aerial scout airship for the British Royal Navy. She was the first British rigid airship to be built, and was constructed...
, named the ‘Mayfly’, on 22 May 1911. The 38 ft (11.6 m) mast was mounted on a pontoon, and a windbreak of cross-yards with strips of canvas were attached to it. However, the windbreak caused the ship to yaw badly, and she became more stable when it was removed, withstanding winds gusting up to 43 miles per hour (19.2 m/s) . Further experiments in mooring blimp
Blimp
A blimp, or non-rigid airship, is a floating airship without an internal supporting framework or keel. A non-rigid airship differs from a semi-rigid airship and a rigid airship in that it does not have any rigid structure, neither a complete framework nor a partial keel, to help the airbag...
s to cable-stayed lattice masts were carried out during 1918 .
British high mast operations
The British mooring mast was developed more or less to its final form at PulhamPulham
Pulham is a village in north Dorset, England, situated in the Blackmore Vale seven miles south east of Sherborne. The village has a population of 211 .-External links:*...
and Cardington
Cardington
Cardington may refer to:*Cardington, Bedfordshire, a village and civil parish in England*Cardington, Shropshire, a village and civil parish in England*Cardington, Ohio, a village in the United States...
in 1919-21 to make the landing process easier and more economical of manpower
Cardington
Cardington may refer to:*Cardington, Bedfordshire, a village and civil parish in England*Cardington, Shropshire, a village and civil parish in England*Cardington, Ohio, a village in the United States...
, and its operation, is abridged from Masefield.
Mooring masts were developed to act as a safe open harbour to which airships could be moored or unmoored in any weather, and at which they could receive (hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
or heliumHeliumHelium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
) gas, fuel, stores and payloadCargoCargo is goods or produce transported, generally for commercial gain, by ship, aircraft, train, van or truck. In modern times, containers are used in most intermodal long-haul cargo transport.-Marine:...
.
The CardingtonCardingtonCardington may refer to:*Cardington, Bedfordshire, a village and civil parish in England*Cardington, Shropshire, a village and civil parish in England*Cardington, Ohio, a village in the United States...
mast, completed in 1926, was an eight sided steelSteelSteel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
girderGirderA girder is a support beam used in construction. Girders often have an I-beam cross section for strength, but may also have a box shape, Z shape or other forms. Girder is the term used to denote the main horizontal support of a structure which supports smaller beams...
structure, 200 feet (61 m) high, tapering from 70 feet (21.3 m) diameter at ground level to 26 inch at the passenger platform, 170 feet (51.8 m) from the ground. Above the passenger platform was the 30 feet (9.1 m) of the conical housing for the mooring gear. A lower platform 142 feet (43.3 m) above the ground accommodated searchlights and signalling gear in a gallery 4 feet (1.2 m) wide.
The top platform, at the height of 170 feet (51.8 m), from which passengers embarked and disembarked to and from the airships, was 40 feet (12.2 m) in diameter and encircled by a heavy parapet. The top rail of the parapet formed a track on which a gangway, let down from the airship, ran on wheels to give freedom for the airship to move around the tower as it swung with the wind. An electric passenger lift ran up the centre of the tower, encircled by a stairway to provide foot access.
The upper portion of the tower, from the passenger platform upwards, was a circular steel turret surmounted by a truncated cone with its top 23 feet (7 m) above the passenger platform. A three-part telescopic arm, mounted on gimbals, projected through an opening at the top, free to swing from the vertical in any direction up to 30 degrees of movement. The top of the arm consisted of a bell-shaped cup mounted to rotate on ball bearingBall bearingA ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races.The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit...
s.
A cable extended through the bell-mouth which, linked to a cable dropped from airship to be moored, enabled the nose of the airship to be drawn down until a cone on the nose locked home into the cup and so secured the airship to the tower. The telescopic arm was then centred, locked in the vertical position, and made free to rotate on a vertical axis so the airship could swing, nose to tower, in any direction of the wind.
In the machinery house at the base of the tower three steam-driven winchWinchA winch is a mechanical device that is used to pull in or let out or otherwise adjust the "tension" of a rope or wire rope . In its simplest form it consists of a spool and attached hand crank. In larger forms, winches stand at the heart of machines as diverse as tow trucks, steam shovels and...
es operated the hauling gear through drums 5 feet (1.5 m) in diameter to give cable hauling speeds of 50 feet a minute.
While an airship approached the mast slowly against the wind a mooring cable was let out from nose to the ground and linked, by a ground party, to the end of the mooring cable paid out from the mast head. The cable was then slowly wound in with the airship riding about 600 feet (182.9 m) above the mast and down wind, with one engine running astern to maintain a pull on the cable. At this point, two side wires – or ‘yaw guys’ – were also connected to cables taken from the nose of the airship to pulleyPulleyA pulley, also called a sheave or a drum, is a mechanism composed of a wheel on an axle or shaft that may have a groove between two flanges around its circumference. A rope, cable, belt, or chain usually runs over the wheel and inside the groove, if present...
blocks some hundreds of feet apart on the ground and thence to winches at the base of the mast.
All three cables were then wound in together, the main pull being taken on the mooring cable while the yaw guys steadied the ship. When all the cable had been wound in an articulated mooring cone on the nose of the airship locked home into the cup on the mast. The mast fitting was made free to rotate as the airship swung with the wind with freedom also for pitch and roll.
A gangway, like a drawbridge, which could be drawn up flush with the nose of the airship, was then let down with its free end resting on the parapet of the platform running round the mast. Passengers and crew boarded and disembarked from the shop under cover along this gangway. About twelve men were needed to moor an airship to a mast.
Montreal
Montreal is a city in Canada. It is the largest city in the province of Quebec, the second-largest city in Canada and the seventh largest in North America...
(Canada), Ismailia
Ismaïlia
-Notable natives:*Osman Ahmed Osman, a famous and influential Egyptian engineer, contractor, entrepreneur, and politician, was born in this town on 6 April 1917....
(Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
) and Karachi
Karachi
Karachi is the largest city, main seaport and the main financial centre of Pakistan, as well as the capital of the province of Sindh. The city has an estimated population of 13 to 15 million, while the total metropolitan area has a population of over 18 million...
(then India, now in Pakistan). None of these survive. Similar masts were proposed at sites in Australia, Ceylon (now Sri Lanka
Sri Lanka
Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka is a country off the southern coast of the Indian subcontinent. Known until 1972 as Ceylon , Sri Lanka is an island surrounded by the Indian Ocean, the Gulf of Mannar and the Palk Strait, and lies in the vicinity of India and the...
), Bombay, Keeling Islands, Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
, Malta
Malta
Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...
, at Ohakea in New Zealand, and in South Africa . The general site specifications can be found in documents produced by the British government.
German mast techniques
German mooring methods differed significantly from those adopted by the British. To quote Pugsley (1981)
"the Germans, originally for ease of transport and for economy, developed a system using much lower masts. The nose of the ship was tethered as before to the mast head, which was only a little higher than the semi-diameter of the ship's hull. The lower fin at the stern was then fixed to a heavy carriage running on a circular railway track around the mast, and this carriage was powered so as to be able to move around the track to keep the ship head on to the wind. In the most sophisticated form, used by the Hindenburg, the rail system was linked to rails running from the mast straight into the airship shed, and the mast was powered so that the ship could be moved mechanically into the shed, complete with mast and stern carriage".
The following account of landing the German airship Graf Zeppelin
Graf Zeppelin
Graf Zeppelin may refer to:*Count Ferdinand von Zeppelin , German officer and engineer, founder of the Zeppelin airship company *LZ 127 Graf Zeppelin, the first airship named after Count Zeppelin...
is abridged from Dick and Robinson (1985) :
Before attempting a landing, contact was made by radio or flag signals with the ground crew to determine the ground temperature and wind conditions. For a normal calm weather landing the ship was trimmed very slightly nose down, as this gave a better gliding angle and the ship almost flew herself down. A smoky fire was started on the ground to show the wind direction. The ship then made a long approach with a rate of fall of 100 feet per minute, and the lines were dropped when she was over the landing flag. When conditions were unusual, as in gusty and bumpy weather, the Graf was weighed off a little light, and the approach had to be fast and preferably long and low.
When the airship was over the field the engines had to be reversed for some time to stop her, and this also helped to get the nose down. Yaw lines dropped from the ship's nose were drawn out to Port and Starboard by thirty men each, while twenty more on each side pulled the ship down with spider lines (so called because twenty short lines radiated like the legs of a spider from a block). When the airship reached the ground, fifty men held the control car rails and twenty held those of the after car. With thirty men in reserve, the ground crew totalled two hundred men.
The ground crew would then walk the Graf to a short, or ‘stub’, mast, to which the nose of the airship would be attached. The airship would then rest on the ground with its rear gondola attached to a movable weighted carriage that enabled the airship to swing around the mast with the wind. In some places the stub mast was mounted on rails and could be drawn into the airship hangar, guiding the nose of the ship while the tail was controlled by the carriage attached to the rear gondola. Airships designed for landing on the ground had pneumatic bumper bags or undercarriageUndercarriageThe undercarriage or landing gear in aviation, is the structure that supports an aircraft on the ground and allows it to taxi, takeoff and land...
wheels under the main and rear gondolas (or tail fin).
Dick states that the Germans never used mooring masts until the Graf Zeppelin entered service in 1928, and never moored to high masts. To some extent this probably reflects the conservatism of the Zeppelin company operations. Long experience in handling airships in all sorts of conditions was valued and innovations or significant changes in practice were unlikely to be adopted unless clear advantages were apparent.
United States
In the US a mix of techniques were applied, and airships moored to both high and stub masts. Large ground crews (or ‘landing parties’) of up to 340 men were required to manage the large airships and at landing or on the ground, before they could be attached to the stub mast.Being part of a ground crew was not risk-free. In gusty conditions, or if mis-handled, an airship could suddenly rise. If the ground crew did not immediately let go of the handling lines they risked being carried off their feet. In one famous incident captured on movie film in 1932, during the landing of the US airship Akron
Akron
-Settlements:Canada* Akron, OntarioSouth Africa* Akron, South AfricaUnited States* Akron, Alabama* Akron, Colorado* Akron, Indiana* Akron, Iowa* Akron, Michigan* Akron, New York* Akron, Pennsylvania* Akron, West Virginia* Akron Township, Illinois...
, three men were carried off their feet in this way, two to fall to their deaths after a short time. The third managed to improve his hold on the handling rope until he could be hauled into the airship .
Ship-mounted mooring masts
Over time the airships , , and all moored to the mast mounted at the stern of the ship, and operated using her as a base for resupply, refuelling and gassing.
The Spanish seaplane carrier Dédalo
Spanish seaplane carrier Dédalo
Dédalo was a Spanish seaplane and balloon carrier, the first of two ships of the Spanish Navy to carry this name. She entered in service in 1922 and was written off in 1936, after taking part in the Second Moroccan War, where her aircraft were instrumental to the successful landing of...
(1922–1935) carried a mooring mast at the bow to cater for small dirigibles carried on board.
Modern mast operations
Smaller mobile masts have been used for small airships and blimps for a long time. They may be wheel or track-mounted, and can be operated by a small crew. The general operating principle is broadly similar to the larger masts. Modern blimps may operate from mobile masts for months at a time without returning to their hangars.External links
- Although principally focused on HM airship R101, this youtube clip shows the R101 releasing from and landing to the Cardington mast.
- The first part of this youtube movie clip shows the USS Macon being walked out of its shed on a mobile stub mast, and releasing from the mast for flight.
- This clip shows the USS Akron being moved out of its shed on a mobile stub mast, and illustrates some of the difficulties of handling large airships on the ground.
- Clip showing two modern mobile mast trucks and something of their operation, and glimpses of a US stub mast and the British R101 at the Cardington mast.